TM 750-245-4
DEPARTMENT OF THE ARMY TECHNICAL MANUAL
TECHNICAL MANUAL
DIRECT SUPPORT, GENERAL SUPPORT
QUALITY CONTROL INSPECTOR'S
INSPECTION CRITERIA
HEADQUARTERS, DEPARTMENT OF THE ARMY
25 JANUARY 1971
*TM 750-245-4
TECHNICAL MANUAL
NO.750-245-4
HEADQUARTERS
DEPARTMENT OF THE ARMY
WASHINGTON, D.C., 25 January 1971
}
Direct Support and General Support
QUALITY CONTROL INSPECTOR'S INSPECTION CRITERIA
Paragraph
Page
LIST OF ILLUSTRATIONS.............................................................................................................................................ii
LIST OF TABLES..........................................................................................................................................................iii
CHAPTER 1
INTRODUCTION .................................................................................
1-1 thru 1-8
1-1
CHAPTER 2.
Section
I.
II.
III.
IV.
CLEANING, PAINTING, AND FINISHING
Introduction..........................................................................................
Cleaning ..............................................................................................
Painting and finishing...........................................................................
Special procedures for magnesium ......................................................
2-1, 2-2
2-3 thru 2-6
2-7 thru 2-10
2-11 thru 2-15
2-1
2-1
2-1
2-3
CHAPTER 3.
Section
I.
II.
III.
IV.
V.
VI.
VII.
VIII.
ELECTRICAL AND ELECTRONIC EQUIPMENT
Introduction .........................................................................................
Chassis assemblies..............................................................................
Electrical wiring....................................................................................
RF cables and waveguides ..................................................................
Plugs and jack assemblies ...................................................................
Servo mechanics .................................................................................
Batteries ..............................................................................................
Miscellaneous items.............................................................................
3-1 thru 3-3
3-4 thru 3-9
3-10 thru 3-13
3-14 thru 3-16
3-17, 3-18
3-19 thru 3-22
3-23 thru 3-28
3-29 thru 3-34
3-1
3-1
3-2
3-13
3-18
3-18
3-18
3-19
CHAPTER 4.
MECHANICAL EQUIPMENT ...............................................................
4-1 thru 4-16
4-1
CHAPTER 5.
Section
I.
II.
III.
HYDRUALIC AND PNEUMATIC EQUIPMENT
Introduction..........................................................................................
Hydraulic components..........................................................................
Pneumatic components........................................................................
5-1 thru 5-3
5-4 thru 5-7
5-8 thru 5-11
5-1
5-1
5-2
CHAPTER 6.
OPTICAL EQUIPMENT .......................................................................
6-1 thru 6-3
6-1
CHAPTER 7.
Section
I.
II.
III.
IV.
SOLDERING
Introduction..........................................................................................
Inspection procedure............................................................................
Acceptance and rejection criteria .........................................................
Comparison standards .........................................................................
7-1, 7-2
7-3 thru 7-9
7-10, 7-11
7-12 thru 7-21
7-1
7-1
7-7
7-9
CHAPTER 8.
Section
I.
II.
III.
WELDING
Introduction..........................................................................................
Types of weld and processes ...............................................................
Weld inspection ...................................................................................
8-1 thru 8-3
8-4 thru 8-12
8-13 thru 8-26
8-1
8-2
8-4
CHAPTER 9.
Section
I.
II.
III.
ADHESIVE BONDING, POTTING, EMBEDDING, AND SEALING
Introduction..........................................................................................
Adhesive bonding ................................................................................
Potting, Embedding, and Sealing .........................................................
9-1,9-2
9-3 thru 9-9
9-10 thru 9-16
9-1
9-1
9-3
CHAPTER 10.
Section
I.
II.
III.
LUBRICATION
Introduction..........................................................................................
Application ...........................................................................................
Inspection procedures ..........................................................................
10-1, 10-2
10-3 thru 10-5
10-4 thru 10-3
10-1
10-1
10-1
CHAPTER 11.
PRESERVATION, PACKAGING, AND PACKING................................
11-1 thru 11-9
11-1
APPENDIX A. REFERENCES
A-1
B. GLOSSARY
B-1
INDEX
......................................................................................................................................................... I-1
*This manual supersedes TM 750-245-4, 8 October 1969.
i
TM 750-245-4
LIST OF ILLUSTRATIONS
Number
3-1
3-2
3-3
3-4
3-5
3-6
3-7
3-8
3-9
3-10
3-11
3-12
3-13
3-14
3-15
3-16
3-17
3-18
3-19
3-20
3-21
3-22
3-23
3-24
3-25
3-26
3-27
3-28
3-29
3-30
3-31
3-32
4-1
4-2
4-3
4-4
4-5
4-6
4-7
8-1
8-2
8-3
8-4
8-5
8-6
8-7
8-8
8-9
8-10
8-11
8-12
8-13
8-14
8-15
8-16
11-1
11-2
11-3
11-4
11-5
11-6
11-7
Title
Page
Stripping single conductor................................................................................................... 3-3
Stripping shielded conductor............................................................................................... 3-3
Single and multiple conductor shield breakout .................................................................... 3-3
Single splice in line............................................................................................................. 3-4
Single splice-pgitail............................................................................................................. 3-4
Single splice-preinsulated ................................................................................................... 3-4
Multiwire splices ................................................................................................................. 3-4
Pigtail splice with shield carried through.............................................................................. 3-5
Typical crimping procedure................................................................................................. 3-6
Crimping individual shield termination ................................................................................ 3-7
Crimping group shield termination ...................................................................................... 3-7
Crimping floated shield termination..................................................................................... 3-8
Insulated, non-insulated, and flag terminal crimps .............................................................. 3-8
Crimping completed ferrule assembly................................................................................. 3-8
HYRING crimping procedure .............................................................................................. 3-9
Crimping insulated conductors.......................................................................................... 3-10
Equal spacing ................................................................................................................... 3-11
Vibration bend .................................................................................................................. 3-11
Clove hitch and square knot ............................................................................................. 3-11
Running stitch................................................................................................................... 3-11
Single lock stitch method .................................................................................................. 3-11
Single lock switch completed ............................................................................................ 3-11
Double lock stitch ............................................................................................................. 3-11
Double lock stitch completed ............................................................................................ 3-11
Serve at point of origin ..................................................................................................... 3-12
Serve method of typing..................................................................................................... 3-12
Spot tie............................................................................................................................. 3-12
Service loop ..................................................................................................................... 3-12
Termination procedures coaxial cable, using series N connectors..................................... 3-14
Coaxial termination using RG and 71 / U connectors ........................................................ 3-15
Coaxial termination procedure using improved series BNG connectors............................. 3-16
Finishing and termination of coaxial connector to coaxial fitting........................................ 3-17
Screw thread check ............................................................................................................ 4-3
New hole preparation.......................................................................................................... 4-4
Swaging type insert installation........................................................................................... 4-4
Removal of key type insert ................................................................................................. 4-5
Key type insert installation .................................................................................................. 4-5
Driving the keys down......................................................................................................... 4-5
Blind nut assembly installation............................................................................................ 4-5
Master chart of welding processes ...................................................................................... 8-1
Basic types of welds ........................................................................................................... 8-2
Offcenter welds .................................................................................................................. 8-5
Cracked welds .................................................................................................................... 8-5
Deformed welds.................................................................................................................. 8-6
Splatter weld....................................................................................................................... 8-6
Blow hole............................................................................................................................ 8-7
Pitted weld.......................................................................................................................... 8-8
Excessive surface fusions................................................................................................... 8-8
Setdown ............................................................................................................................. 8-7
Methods of pull testing........................................................................................................ 8-8
Lack of fusion caused by insufficient heat........................................................................... 8-8
Excessive heat and pressure resulting in shrinkage cavities ............................................... 8-9
Proper penetration .............................................................................................................. 8-9
Improper heat balance........................................................................................................ 8-9
Proper heat balance (Does not exist per msc)................................................................. 8-10
Functions of cushioning .................................................................................................... 11-2
Humidity indicators ........................................................................................................... 11-3
Deficiencies...................................................................................................................... 11-4
Method of preservation, packaging, and packing .............................................................. 11-5
Method of preservation and packaging ............................................................................. 11-6
Method of packaging and packing missile items ............................................................... 11-6
Package failure................................................................................................................. 11-6
ii
TM 750-245-4
LIST OF TABLES
Number
1-1
3-1
4-1
4-2
7-1
7-2
7-3
7-4
7-5
7-6
7-7
7-8
7-9
7-10
7-11
7-12
10-1
B-1
B-2
B-3
B-4
B-5
B-6
Title
Page
Personal qualifications........................................................................................................ 1-2
Stitch spacing ................................................................................................................... 3-12
American Standard Thread Gage Tolerances ..................................................................... 4-2
Tolerances on Half Angle of Thread, Minutes ..................................................................... 4-2
Mechanical connections...................................................................................................... 7-2
Insulation clearance for solder joints ................................................................................... 7-8
Workmanship ..................................................................................................................... 7-9
Insulation.......................................................................................................................... 7-13
Stranded conductors inspection criteria............................................................................. 7-14
Cup connectors................................................................................................................. 7-15
Solder coverage-printed circuit ......................................................................................... 7-16
Solder coverage-connector pins........................................................................................ 7-17
Solder coverage-turret terminals....................................................................................... 7-18
Solder coverage-bifurcated terminals ............................................................................... 7-19
Soldering of components .................................................................................................. 7-20
Soldering of hook leads .................................................................................................... 7-21
Types of gear wear observed after use ............................................................................. 10-2
Units of measure .............................................................................................................. B-15
Temperature conversion table .......................................................................................... B-17
Color codes ...................................................................................................................... B-19
Component color code marking ........................................................................................ B-20
Solder alloy temperature ranges ....................................................................................... B-21
Fuses-style, voltage current ratings and characteristics .................................................... B-22
iii
TM 750-245-4
CHAPTER 1
INTRODUCTION
the inspector and the more definite becomes the fine
line between over and under inspection.
b. Each inspector must utilize all the technical data
and tools to assist him in defining and stopping on this
fine line. In the final analysis, an inspector, must
depend on his own opinion for many decisions. This
opinion must be as accurate as possible.
The
successful accomplishment of the mission and the
safety of its personnel depend on such decisions.
1-1. General
This technical manual covers the inspection criteria for
use by quality assurance/quality control (QA/QC)
inspection personnel at the direct (DS) and general
support (GS) maintenance levels. In cases of conflict
between this manual and the system documentation, the
system documentation will take precedence.
1-2. Purpose
The purpose of this manual is to provide information as
well as a check list for use by QC inspection personnel.
Some of the information is taken from other sources and
included to provide the QC inspection personnel with an
all inclussive document. The purpose for information on
repair procedures being included is to help QC
inspection personnel during in-process inspection which
must be made. Reference to appendix A along with the
information in this manual should provide the QC
inspection personnel with all the required information he
needs to perform his required duties.
c. In accomplishing the mission, each inspector
accepts a very important role during in-process and final
acceptance inspection. Inspection of materiel during
process helps to assure that those subassemblies which
will be used in major assemblies or items are being
repaired to be as near the original as possible and as
reliable as possible. Final acceptance inspection must
be a guarantee to the customer that the items received
are the best available.
d. Inspectors are the final link in the DS and GS
maintenance chain. This chain can be the weak link or
the strong link. The successful completion of tactical
missions are based to a great extent on the strength of
this link.
e. This document is intended to further assist
every inspector in making the correct decision every
time. It will be revised from time to time, as required, to
make it a more useful inspection tool.
1-3.
Report of Equipment Publication Improvements
Report of errors, omissions, and recommendations for
improving this publication by the individual user is
encouraged. Reports should be submitted on DA Form
2028 (Recommended Changes to DA Publications) and
forwarded direct to Commanding General, U.S. Army
Missile
Command,
ATTN:
AMSMI-SMPT(NMP),
Redstone Arsenal, Alabama 35809.
1-7. Inspector's Authority
a. To aid every inspector in performing his duties,
there exists adequate written authority from higher
headquarters. Such authority should be maintained for
each inspector to thoroughly read and remember.
b. Basically the stamp and signature of an
inspector is final. It is not subject to contradiction by
anyone except his immediate supervisor. Decisions of
in-process inspectors are equally as valid for both
operating personnel and other inspection personnel.
Simply, if an item is defective, that is the unchallenged
decision. It is not to be used until repaired to the
satisfaction of this same inspector and until it is
acceptable, this decision must also not be challenged.
c. This authority places a heavy responsibility on
the shoulders of every inspector. By his action he can
either cause the expenditure of funds for unnecessary
1-4. References
The reference documents included as Appendix A are
for the inspector's use.
He should consult these
references for more detailed information and operational
procedures. Use of these references will increase the
inspector's knowledge, experience, and effectiveness.
1-5. Glossary
The glossary included as Appendix B carries a complete
listing of definitions, tables, charts, and other references
of benefit to the inspector.
1-6. Quality Control Inspector's Role
a. The mark of a good inspector is his ability to
inspect just enough to assure compliance with all
requirements and no more. To do less results in a
below-standard product; to do more results in production
loss and an unnecessary expenditure of funds. The
more knowledge and experience, the more capable is
1-1
TM 750-245-4
the degree to which personnel aspire to gaining and
conforming to these qualities.
d. Factors Required for a Successful Workmanship
Standards Program. There are many factors which will
determine the success of a QC inspection program.
The following is not all inclusive but will give the
inspector a broad view of factors required:
(1) Satisfactory working conditions: proper
lighting, quietness, temperature, space, clean air, etc.
(2) Standard Inspection Procedures (SIP's)
for all inspection operations.
(3) Advance planning and scheduling.
(4) Carefulness.
(5) Conscientious, qualified, and cooperative
personnel.
(6) Consistent and systematic policies.
(7) Reliable inspection procedures.
(8) Close adherence to procedures.
(9) Division of work into elements.
(10) Work simplification and improvement.
(11) Neatness, cleanliness, orderliness.
(12) Following safety regulations.
(13) Understanding job requirements.
(14) Knowing where to, and getting, technical
help when required.
(15) Locating and correcting causes of
substandard performance beyond the control of
individual workers.
(16) Keeping close control over the number
and kinds of inspection stations.
(17) Having ready information regarding
output, possibilities, and goals.
(18) Adequate auditing of operations.
rework or can cause a malfunction of an item in the
hands of its user by accepting a defective item. This
responsibility requires a thoroughly competent, well
trained individual.
1-8. QC Inspector's Standards
This document itself is essentially a set of quality
oriented standards. "There is no substitute for quality,
and quality is proportional to the inspector's
workmanship." The extra care for superior workmanship
spells the difference between superior quality and
average quality.
a. Objective. To achieve the necessary inspection
training, depth of experience, and proficiency for
excellence in workmanship.
b. Responsibility.
The responsibility for good
workmanship lies with the commander. The inspector
insures compliance with that policy and his success
depends upon his qualifications, attitude, cooperation,
orderliness, and coordination with other activities.
Working facilities and conditions are seldom ideal, but
thought, team work, and adherence to rules and
procedures will produce optimum safety, neatness,
efficiency, and job satisfaction for the circumstances
prevailing.
c. Personnel. Quality of inspection personnel is
proportional to education, training, skill, adaptability and
personal characteristics. Special training is required and
must be as thorough as practicable, whenever new
systems are fielded, or new items are introduced,
additional training is required.
The most relevant
characteristics for inspection personnel are listed in
table 1-1. This depicts a suggested rating sheet to
insure the best possible workmanship level.
The
inspection program will succeed in direct proportion to
Table 1-1. Personal Qualifications
Fair
a. Education
b. Attitude
c. Judgment
d. Self control
e. Experience
f. Skill
g. Reliability
h. Responsibility
i. Quality consciousness
j. Safety consciousness
k. Economy consciousness
1-2
Average
Above average
TM 750-245-4
CHAPTER 2
CLEANING, PAINTING, AND FINISHING
Section I. INTRODUCTION
The safety aspects of cleaning, painting, and finishing
are well-defined in existing maintenance instructions
and regulations and are not discussed here. The
inspector is cautioned, however, to be aware of these
requirements to insure that noncompliance does not
cause poor quality performance.
2-1. General
This chapter covers the inspection requirements for
cleaning, painting, and finishing.
These three
requirements are grouped into this chapter because of
their applicability to all components.
2-2. Safety
Section II. CLEANING
specifications and maintenance standards.
This
inspection should also include inspection of cleaning
materials to insure that the proper materials are being
used.
2-3. General
a. The QC inspector must insure that all items on
which maintenance has been performed are clean. This
will require in-process inspections as well as final
inspection.
b. The objective of cleaning is the removal of
contaminants which would impair equipment operation.
An item is satisfactorily clean that has been cleaned by
one of the specified processes and no smudge appears
when inspected by wiping with a clean, lint-free tissue
paper. Stains caused by fungus or corrosion are
acceptable as long as the parts are functionally
satisfactory.
2-6. Cleaning Inspection
These inspections insure that the equipment is clean
and ready to be returned to service. The QC inspector
should reject any equipment which shows the following
defects:
a. Loose, spattered, or excess solder; metal chips,
dust, filings, dirt, sand, carbon; wire ends and insulation;
phenolic or ceramic chips; foreign material, of any kind,
including any particles that could loosen or become
dislodged during the normal life of the equipment.
b. Fungus, mold, or any other organic growth on
any item.
c. Oil, grease, cooling compound, wax, or other
residue on items not requiring lubricants or protective
coatings.
d. Rust, scale, powder, or other corrosion products.
e. Paint on rubber gaskets, seals, plastic or
ceramic items, glass and mechanical surfaces.
f. Alkaline or acid residues. (Checked with litmus
paper.)
2-4. Facility
Random inspections of equipment should be performed
by the quality control inspector. These inspections will
determine that the equipment and cleaning facilities are
adequate. Any equipment which is not in full accord
with applicable cleaning standards should be regarded
as defective. Corrective measures must be taken
immediately to insure proper cleaning of applicable
components.
2-5. Processes
Each cleaning process in use should be inspected
periodically to insure conformance to applicable
Section III. PAINTING AND FINISHING
2-7. General
a. Painting and finishing are covered in the same
section because of their interrelationship. The purpose
of painting and finishing of material is to improve its
general appearance, prolong its life, and keep corrosion
factors to an absolute minimum.
b. Thorough cleaning by an approved technique is
the first essential procedure in any effective painting or
finishing method. No painting or finishing method will
protect a part if contaminants or contaminating
2-1
TM 750-245-4
procedures are being properly performed. The inspector
should halt all painting operations found defective and
insure that corrective action is taken. The inspector will
generally inspect:
(1) Equipment after proper cleaning is
accomplished for evidence of scale, dirt, paint peel,
blisters, etc.
(2) Proper painting in accordance with the
applicable requirements of the particular item. Refer to
existing system documentation for these requirements.
(3) To insure that moving parts and machined
surfaces, unless otherwise specified, are protected from
paint.
(4) To insure that exposed bearings, glass,
rubber gaskets, canvas, and gears will not be exposed
to paint.
(5) Condition of surface prior to painting to
insure that all moisture, soil, and contamination has
been removed.
b. Finishing. The inspector should perform an inprocess inspection, periodically, to insure that finishing
requirements are being met. He should also perform an
in-process inspection anytime items are not meeting the
final finish requirements.
All defects should be
corrected before permitting additional finishing of items.
The inspector's in process inspection should generally
insure that:
(1) Contaminants which absorb moisture or
accelerate corrosion, are removed as soon as possible.
Oil, grease, and adherent nonporous oxide coatings
may afford some protection against corrosion, but in
most cases, must be removed before corrosionpreventive compounds, chemical protective finishes,
electroplated metal, or paint finishes are applied.
(2) Materials used for finishing, which have
not been accepted previously, are inspected and sample
tested to determine compliance with the requirements
as specified in the system documentation.
(3) Items to be painted after finishing are
clean and that the finish meets the required standard.
(4) The inspector may, at his discretion, have
test specimens made from the same type metal, coated
identically, and processed concurrent with the processed
items. These specimens should be checked for proper
thickness (generally 4 to 5 mils), and final finish to
insure proper processing.
residues which accelerate corrosion or interface with
adhesion or continuity of the preservatives are present
on the surface of the part prior to application of the paint
or finish. Improper cleaning makes all subsequent
painting and finishing operations ineffective.
c. Metal items which are to be given chemical
protective finishes or coatings must be cleaned so that
their surfaces are completely free of dust, grit, grease,
oil, acid, alkaline, and salt residues, corrosion, and other
contaminants. The presence of contaminants may
cause the fissures, or other surface defects that are
points of entry for corrosive substances and thus make
the coating ineffective. The cleaning method chosen
must be most suitable for the material of which the part
is made and the service requirements of the finished
item.
2-8. Facilities
a. Painting. Painting shall be done in a clean, dry,
well-ventilated space.
It is preferred that the air
temperature be between 60 to 90 degrees and the
relative humidity not over 65 percent. Painting should
not be done when the temperature is below 50 degrees
Fahrenheit or when the humidity is above 85 percent.
Materials shall be thoroughly mixed and there shall be
no settling or separation of ingredients during painting
operations. Unless otherwise specified, coatings may
be applied by any method that will insure the application
of a smooth, uniform, continuous film, free from direct
overspray, runs, sags, blisters, orange peel, or other
imperfection. Unless otherwise specified, baking of
coats of paint shall be done at a temperature of 250
degrees Fahrenheit for 45 minutes. Freshly painted
material shall not be exposed to conditions that will
harm the paint. Pretreatment coating (primer wash,
pretreatment blue, formula 117-B for metals) shall be
applied by spraying, brushing, roller coating or
swabbing. However, in the case of magnesium, this
coating shall not be applied unless the magnesium has
an adequate protective film and conforms to the
appropriate system documentation.
b. Finishing.
The finish facilities are usually
separate from other work areas. The requirements are
generally the same as for the painting area above, with
the exception of temperature. Application of finish coats
does not require temperature control as does painting.
2-9. In-Process Inspection
a. Painting. The inspector should perform an inprocess inspection periodically. He should also perform
an in-process inspection anytime painted items are not
meeting the final painting inspection requirements. Inprocess inspections are made to determine that all
2-10. Final Inspection
a. Painting.
The inspector should inspect all
painted items. These inspections will insure that the
item meets required standards and is ready for use.
2-2
TM 750-245-4
satisfactory hiding power, color, gloss, and smoothness.
If the surface does not meet these requirements, it
should be repainted. Removing the existing paint may
not be necessary.
(7) Exterior surfaces or trailers, vans,
antennas, interior walls and ceiling of vans, and
surfaces of cabinets and consoles shall be smooth,
continuous and like new. Touch up or spot painting will
be allowed for areas of up to 1/2-square foot.
b. Finishing. The inspector should inspect the
items requiring a finish. Items requiring painting after a
finish coat should be inspected in accordance with
paragraph a above. The inspector will ascertain that the
item meets the required standards and is ready to be
returned to the using organization.
(1) shall be smooth, fine grained, adherent
and free from visible blisters, pits, nodules, porosity,
indications of burning, excessive edge build-up and
other detrimental defects. Superficial staining shall not
be cause for rejection.
(2) Slight discoloration from baking will not be
cause for rejection.
(3) Cadmium plating should have no white
corrosion products on the surface. Bright or dull finish is
acceptable.
(4) Presence of black-silver oxide or silver
sulphide (tarnish) shall not be cause for rejection of
silver-plated items.
(5) All coatings shall be visually checked for
continuity and uniformity.
(6) Any items which reveal bare spots due to
some contamination must be completely reworked.
Criteria are:
(1) Major items must be the correct color in
accordance with applicable system documentation.
(2) The correct color of items disassembled
from major items shall be recorded on the inspection
tag.
(3) There shall be no dried overspray, runs,
sags, blisters, dirt, grit, orange peel, or other
imperfections. The imperfection shall be removed and
the local area repainted.
(4) There shall be no peeling, flaking, or other
evidence of poor adhesion. When poor adhesion is
indicated, the paint on the entire surface must be
removed and the surface cleaned and repainted.
(5) The painted items shall be examined for
adhesion after the coated items have dried for a
minimum of 24 hours for quick-drying and baking
systems, and for a minimum of 72 hours for all other
systems. Water-resistant, pressure-sensitive adhesive
tape (3/4-inch wide) shall be used. Press a 2-inch
length of a somewhat longer piece firmly onto a flat or
cylindrical surface of the item, rubbing out all air bubbles
under the tape. Allow approximately 10 seconds for the
test area to return to room temperature. Grasp a free
end of the tape and at a rapid speed, strip it from the
item by pulling the tape back upon itself at 180 degrees
(in such a manner that the tape is folded back-to-back
during the procedure). Observe for bare spots where
the paint is removed. Disregard flecks of paint on tape
where the underlying metal or phosphate coating is not
visibly exposed.
(6) Paint
shall
have
uniformity
and
Section IV. SPECIAL PROCEDURES FOR MAGNESIUM
2-11. General
a. The cleaning, finishing, and painting of
magnesium is covered in this section because of its
unusual characteristics.
b. Magnesium is a silver-white, light, malleable
ductile, bivalent, metallic element that occurs
abundantly in nature. It is used in metallurgical and
chemical processes, photography and signaling
equipment. It is highly flammable, and is a good
pyrotechnic because of the intense light it produces on
burning. Structurally, it is used as an alloy.
c. The material must be treated with certain
finishes to prevent excessive corrosion, indicated by a
powdery substance. Special and cautious techniques
must be utilized while machining or cleaning this metal
due to its highly flammable composition. It is often used
in design, when weight limitations are imperative.
2-12. Facilities
All treatment equipment should be inspected at random
by the quality control inspector. The inspections are
made to determine that the equipment and facilities for
cleaning, treating, and painting of magnesium are
adequate. He also should insure that proper safety
equipment is available. If samples of treatment solution
are taken which reveal inadequate solutions or safety
hazards, corrective action must be taken immediately by
the inspector.
2-13. Magnesium Cleaning
a. Acid is used to clean magnesium by pickling or
to remove oxide layers of old chemical finishes, burned
on drawing and forming lubricants and other waterinsoluble or non-emulsifiable substances.
2-3
TM 750-245-4
piece shall be determined from the difference of the two
measurements.
c. Other Tests. Treated pieces shall be tested for
conformance with any special requirements specified in
the drawing. The tests shall be performed according to
the methods specified therein.
d. Rejection.
(1) In the event unsatisfactory quality is
detected in the processing treatment being used, the
inspector will promptly notify processing personnel to
take necessary corrective action. All work which was
processed under doubtful conditions of the solution
utilized will be rejected and reprocessed to the
satisfaction of the inspector.
(2) If a sample fails to conform to the
requirements of this document, all items being
processed as represented by the sample will be
rejected.
Rejected items may be submitted for
acceptance after the items have been reprocessed.
Reprocessed items are subject to 100 percent
inspection in order to determine if defects still remain.
2-15. Magnesium-Final Inspection
a. All equipment fabricated of magnesium will be
inspected for the proper smoothness and finish.
b. Any detected bare spots will be refinished as
required.
c. Any signs of apparent contamination such as
dirt, grease, and pits will be removed and any necessary
actions required will be taken to correct the problem.
d. Check those areas that specify special painting,
etc.
e. Scratches which must be removed and
reworked and / or finished.
f. Coatings shall be visually examined for
continuity and uniformity.
g. Coatings shall be checked for dry film thickness
as required by this document and / or the applicable
system documentation. Small steel panels prepared
with films should be used as comparators to the item
being inspected.
h. The thickness requirement generally shall be
considered met when the coating is of sufficient
thickness to completely cover and impart characteristic
color of the coating to the surface. Generally, four mils
thickness is sufficient if a surface is completely stripped;
otherwise, a five mil thickness is acceptable and
adequate.
b. Generally, magnesium castings which have
been formerly sandblasted, are pickled or treated with a
sulfuric or nitric-acid solution.
Treatment should
continue until 0.002-inch surface is removed, if
dimensional requirements permit.
c. Old paint coatings are usually removed by use
of (caustic) liquid paint remover. This operation should
be followed by a wash or rinse to thoroughly remove and
neutralize the alkaline.
d. Insure proper treatment is used as required.
The following can be used for magnesium treatments:
(1) Chrome pickle treatment.
(2) Dichromate treatment.
(3) Galvanic anodizing treatment.
(4) Chromic acid brush-on treatment.
(5) Fluoride anodizing process plus corrosion
preventive treatment.
(6) Chromate treatment.
e. Random sampling for visual examination and
workmanship shall be conducted.
f. All items exposed, to weather shall be examined
very closely for any evidence of corrosion or
deterioration of finish. If there is any evidence of
corrosion, the finish must be removed to bare metal and
cleaned of any corrosion or corrosion products and
finished using procedures provided.
2-14. In-Process Inspection
a. Product Examination. Samples of treated parts
shall be visually examined to determine conformance to
workmanship standards, quality of the treated surface,
and any other requirements specified by the system
documentation. A visual examination of the processed
surface shall be made for complete and uniform
coverage. Surfaces shall be examined for coloring and
general characteristics, described herein, particular to
the type treatment being examined, which shall be an
indication of satisfactory time of treatment and condition
of solution.
b. Dimension Change Determination.
The
thickness of each piece selected prior to treatment shall
be determined by measuring with a micrometer which
reads accurately to 0.0001 inch. The pieces shall then
be processed concurrently with the remainder of the lot.
The pieces shall be distributed throughout the various
bitches during processing so as to be representative of
the entire lot. The thickness of each piece shall be
determined after treatment by measuring the same
location as before. The dimensional changes of each
2-4
TM 750-245-4
CHAPTER 3
ELECTRICAL AND ELECTRONIC EQUIPMENT
Section I. INTRODUCTION
MWO application, and inventory to insure that there are
no missing items.
b. In-Process Inspection.
This inspection is
performed to insure that procedures, processes,
adjustments required during assembly, parts conform to
the prescribed standards, and that workmanship is in
accordance with approved methods and procedures.
Inspections are made to protect product quality and
integrity of processing.
Evidence of unacceptable
workmanship or materials is cause for rejection of the
item and much closer inspection of the defects and
causes.
c. Final Inspection. This inspection is performed to
insure that all deficiencies have been corrected,
workmanship meets the standards, final configuration is
correct, and that the item is operational within the
tolerances and limits established for the item. Those
items requiring maintenance calibration checks will have
a DA Label 80 attached to indicate accomplishment of
the required checks.
3-1. General
This chapter covers the inspection criteria for electrical
and electronic equipment. The chapter is arranged in a
normal inspection manner; chassis, electrical wiring,
plugs and jacks, switches and controls, motors, power
sources, and assembly components.
Soldering,
because of its extensive coverage and importance, is
included separately as chapter 7.
3-2. Definitions, Abbreviations, and Terms
The inspector should refer to Appendix B for the
definitions, abbreviations, and terms applicable to
electrical and electronic equipment.
3-3. Types of Inspection
a. Initial or Receiving Inspection. This type of
inspection is not normally accomplished by the QC
inspector. The QC inspector may perform an initial or
receiving inspection when he determines that it is
necessary. The inspection is performed to determine
the repairs required, proper identification of equipment,
Section II. CHASSIS ASSEMBLIES
before rejecting an item because of dents and
scratches.
b. The inspector must determine, with the aid of
depth gages and other suitable equipment, whether to
reject or repair. In the majority of cases, repair can be
accomplished. Any defect which would impair safety of
personnel or equipment must be rejected.
3-4. General
This section covers the inspections required on the
chassis assemblies with respect to attaching hardware,
dents, scratches, weldments, finish and identification.
3-5. Attaching Hardware
a. Attaching hardware is basically divided into two
broad categories: threaded and nonthreaded. Threaded
types include nuts, screws, bolts, studs, etc.
Nonthreaded types include rivets, springloaded clamps,
and pins.
b. Visual inspection will verify that the attaching
hardware is not scarred, battered or deformed by the
tools used in installation; that protective coatings remain
intact and that there is no apparent deficiency in the
hardware used.
3-7. Weldments
The inspector should insure that all weldment repairs
meet the inspection requirements as specified in chapter
8.
3-8. Finish
After repair, the chassis should be capable of meeting
the inspection requirements for finish as specified in
chapter 2.
3-6. Dents and Scratches
a. The location and effect of dents and scratches
upon item operation determines the critical importance
and possible repair or rejection. The inspector should
consult the system maintenance manuals for guidance
3-9. Identification
In accordance with the method of identification
(identification plate, stencil marking, etc.) inspect for
clarity, legibility, and secure attachment.
3-1
TM 750-245-4
Section III . ELECTRICAL WIRING
3-10. General
This section covers the inspection of electrical wiring,
cables and wiring harness assemblies.
Cable
assemblies are identified as interconnecting cables
between two assemblies. Wiring harness assemblies
are identified as internal wiring which connects chassis
internal components. A discussion of electrical cable
and wiring harness repair is covered to give the
inspector a better understanding of what he is to look for
during inspection.
(4) For a solid wire splice, cut back the
minimum of insulation, place ends of wire in stakon
splice connector, solder and crimp.
b. Insulation.
(1) An appropriate cable test set or megger
can be used to determine the insulation resistance. If
insulation requirements for the subject cable are
unavailable, reject on values less than 100 megohms.
(2) Check cable shielding to insure proper
grounding of the shield.
(3) Small holes in vinyl sleeving may be
patched by cementing on a patch of similar material,
using vyna-kote cement. Larger holes may be repaired
by slipping on a length of solid sleeving, or by using split
sleeving large enough to lap 180 degrees. In both
methods, cement with vyna-kote.
(4) Rubber cable jackets may be repaired by
patching and vulcanizing.
(5) Plastic cable jackets may be repaired with
epoxy cement with or without a patch, as necessary.
(6) Conductor splices should be coated with
liquid vyna-kote and then covered with vinyl covered
braided glass.
c. Connectors. The connectors used on cables are
of many configurations and no attempt is made here to
describe them in detail.
Solderless wire wrap
connections are permitted in certain instances of
communication and control circuits where terminal pins
are designed for this type connections. When repairing
or replacing connectors, care must be taken to observe
the order of disassembly of the parts so that they may
be reassembled in the same order. On multi-conductor
cables a template should be used to identify the
conductors while the connectors are being changed.
Care must be taken to orient or polarize the terminals to
assure proper mating of the connectors.
a. Insulation of electrical wiring is done to prevent
failures, grounding, and to keep out moisture which
could cause shorts. Insulation in many cases is used to
prevent electrical shock to personnel and to prolong the
life of the electrical equipment.
b. All splices and connector terminals should be
insulated and in most cases preshrunk in place. The
insulation should extend 1/4 inch beyond the connector
pin or wire which it insulates. It should not be cracked,
torn, checked, or rotted.
c. Insulation covering cable assemblies and
connector ends of wiring harnesses are generally of two
types; nonshrinkable and heat-shrinkable.
Cable
assemblies are usually completely covered by an outer
insulation material; vulcanized rubber or neoprene.
Wiring harness assemblies usually have a "spaghetti"
type insulation which can be slid over the wire
assemblies to cover the bare connections.
3-11. Cable Assemblies
A cable assembly consists of two or more electrical
wires enclosed in a rubber or plastic cover or jacket.
The ends usually terminate in pin type connectors. To
assure a good quality cable repair, in-process inspection
is necessary.
a. Splicing.
(1) Cables may be spliced and used provided
the length is not reduced beyond 90 percent of the
original length. (See paragraph 3-11 b for splicing
procedure.) If the cable is to be returned to the using
unit, the minimum length is determined by operating
conditions. Conductor splices will be soldered unless
.specifically prohibited. Missile cables are normally not
spliced.
(2) Splices will not be made at flexing points.
Splice in a new piece of conductor with joints on either
side of the flexing point.
Spliced joints will be
strengthened by additional sleeving or lacing.
(1) Ends of conductors will be sold-red to the
pins and sockets using a noncorrosive flux. The quality
of soldering is described in chapter 7. Clean the
connector by immersing in trichloroethylene and
brushing between wires, pins, and other components.
Fill backshells, or hoods with sealing compound or
epoxy resin if required.
(2) In the event that the jacket has shrunk
away from the connector, disassemble the connector,
pull the jacket into place against the connector and
secure by winding the linen thread.
(3) Damaged or dirty threads on the
connectors may be made serviceable by chasing the
threads with a die or tap.
(3) For a stranded wire splice, the strands
shall be combed out, interlaced, compressed, and
soldered. For a nonsolder splice, twist the strands, trim
and use a splice connector ("Sta-Kon, two way, butt end.
3-2
TM 750-245-4
3-12. Wiring Harness Assemblies
Wiring harness assemblies are normally used internally
in chassis assemblies. They do not require weather
proofing protection and only in some cases require
potting of plug and jack assemblies. The inspector
should inspect for proper stripping, splices, lacing, wire
color, and proper wire size of replaced wiring.
a. Stripping.
Proper stripping is important to
accomplish a good solid and electrical connection. If
stripping is not properly done, arcing and burning may
result. The inspector will have to perform an in-process
inspection to insure that proper stripping is being
accomplished.
(1) Stripping is usually accomplished by a
mechanical stripping tool or a thermal stripper.
Generally, nonadjustable type mechanical strippers are
used because of the nonavailability of thermal-type
strippers. These mechanical strippers should never be
used on wire sizes 22 or smaller if there is a tendency to
stretch the wire. Also, care should be taken to prevent
nicking or cutting of the wire strands. Nicked or cut wire
strands requires replacement of the wire if enough
length for restripping is not available.
(2) Figures 3-1 through 3-3 show proper
stripping, depending on the termination method. Figure
3-1, dimension A, is the length of the crimp bowel added
to the conductor plus 1/ 16 inch. Figure 3-2 illustrates a
ferrule or dead-end shield termination. Dimension C is
the length of the bowel to be crimped plus 1/16 inch.
For dead-ending, keep shield braid flush, within 1/8 inch
of the shield jacket. Figure 3-3 shows the pigtailing of
shields for grounding. Dimension C is determined by
the application.
Figure 3-2. Stripping shielded conductor.
Figure 3-3. Single and multiple conductor shield
breakout
Figure 3-1. Stripping single conductor.
c. Crimping. All crimping should be accomplished
with properly qualified and calibrated tools.
The
inspector should inspect in-process to insure that the
proper tools are being used. Figures 3-9 through 3-16
are included to assist the inspector in determining that
the crimping is properly done.
d. Lacing. To prevent damage to insulation and
breaking of conductors caused by vibration and other
movements, the wires must be tied, together in
b. Splicing.
The splicing of wiring harness
assemblies is not recommended and should only be
accomplished as specified in the system documentation.
If splicing is to be accomplished tile following figures 3-4
through 3-8 are included to assist the inspector in
determining that the splice is properly done.
3-3
TM 750-245-4
Figure 3-4. Single splice in line.
Figure 3-6. Single splice - preinsulated.
Figure 3-5. Single splice - pigtail.
Figure 3-7. Multiwire splices
bundles or harnesses and secured to the structure or to
a tiebar. Various methods such as continuous lacing,
spot ties, plastic cable ties, plastic tubing, and spiralwrapped plastic tape are commonly used for lacing the
cable trunk. Excessive tension, visible as a deformation
of the outside diameter of the cable trunk, will promote
cold flow of the insulation under the tie. This condition
can result in low insulation value or short circuits.
Preferred methods of lacing and the use of plastic ties
will be discussed in the following paragraphs.
(1) Continuous lacing (figures 3-17 and 3-18).
The materials commonly used for continuous lacing are
lacing tape, cord, or small diameter tubing.
The
stitching should be equally spaced up to the point of
branching or other termination. Where the harness
ending consists of a single wire or a pair of wires, a
clove hitch secured by a square knot is sufficient. In
component assemblies where wires break from the
cable trunk to a termination, the tie should be made a
distance from the branch to provide a sufficient vibration
bend.
(2) Terminating stitches and spot ties. A
clove hitch and a square knot are generally used for
terminating stitches and spot ties (figure 3-19).
(3) Running or single stitches (figure 3-20).
Running or single stitches are successfully used on
insulation that has high potential cold flow
characteristics. It is made by passing the free end of
3-4
TM 750-245-4
CAUTION
Cut the end of nylon straps off flush
with the boss to avoid cuts to hands
from the sharp edges. The plastic
ties may also be used as cable
clamps. Care should be taken that
no cable clamp be placed over a
cable tie.
(9) Service loop (figure 3-28). Where a loop
must be provided to allow opening of an access door,
the harness should be served at the start and end of the
loop. The loop should not be laced, but should be
secured by spot ties or plastic cable ties.
Figure 3-8. Pigtail splice with shield carried
through.
the lacing material around the bundle, over the standing
part, and through the loop.
(4) Single lock stitch (figures 3-21 and 3-22).
The single lock stitch is commonly used for continuous
lacing. It is made by making a single stitch, then
passing the free end under the lacing between the two
stitches and through the loop.
(5) Double lock stitch (figures 3-23 and 3-24).
The double lock stitch is used primarily to prevent lacing
from loosening but is frequently used for complete
lacing. It is made by making two single stitches around
the bundle and securing with a lock stitch.
(6) Spacing of stitches.
The wires in a
finished cable trunk should have a minimum number of
crossovers. Crossovers, if necessary, should be at least
8 inches from the termination. Terminating stitches
should be made at the end of each lacing. The type of
stitch is determined mainly by the type of insulation and
diameter of the bundle. The most commonly used stitch
spacing is indicated in table 3-1.
(7) Serve (figures 3-25 and 3-26). The length
of the serve or endless tie should be equal to
approximately the outside diameter of the wire bundle
and should not exceed 3/4 inch. To prevent the lacing
from loosening, it should be served at the point of origin
and at the point of termination of the lacing. The serve
is used at bundle branches or breakouts and at all
bundle end terminations. The serve is made by forming
a loop along the bundle with the lacing tape, the ends of
the tape toward the bundle end. Wrap the lacing end of
the tape around the bundle and over the loop. Upon
reaching the desired length of serve, pass the lacing end
through the loop and pull the ends away from each
other. Adjust by pulling until the cross is under the
serve. Cut this excess tape from each end of the serve.
(8) Spot ties (figure 3-27). Spot ties are
frequently used in place of continuous lacing. They are
made exactly like the termination ties.
3-13.
Inspection Cables and Wiring Harness
Assemblies
a. After repair of cable and wiring harness, test for
electrical continuity and insulation resistance.
b. Visual inspection may be made according to the
following checklist:
(1) There shall be no fungus growth, oil,
grease, corrosion, or foreign materials (especially
around pins and terminals).
(2) Insulation shall have no cracks, tears,
cuts, fraying, abrasion, burns, or other deterioration
throughout entire length with particular emphasis at
splices and terminations.
(3) Connectors, when required, shall have
proper application of potting.
(4) Terminals and connectors shall not be
twisted, bent, broken, or missing.
(5) Insulator inserts shall not be burned,
cracked, chipped, broken, or contaminated with any
foreign material.
(6) Mounting and connector hardware, dust
covers, and caps, shall not be loose, damaged, or
missing.
(7) Identification markings shall not be
illegible, incorrect, or missing.
(8) Color or number code of wire shall be in
accordance with system documentation or have a
suitable marker indicating correct code on each end.
(9) Pin and socket terminal contacts shall be
securely seated in connector inserts.
(10) Insulator blocks must not be free to be
pulled or pushed out.
(11) Minimum radii of bend for power wires
and cables shall be 10 x od.
(12) Minimum radii of bend for power wires
and cables at terminals or support shall be 3 x od.
(13) Minimum radii of bend for RF cables
enclosed in sleeving shall be 2 x od.
3-5
TM 750-245-4
Figure 3-9. Typical crimping procedure.
3-6
TM 750-245-4
Figure 3-10. Crimping individual shield termination.
Figure 3-11. Crimping group shield termination.
(14) Minimum radii of bend for RF cables
formed from straight sections of cable shall be 5 x od.
(15) Soldering of wire ends. Refer to chapter 7
on soldering.
(16) Wire ends shall be securely attached to
connectors, and shall be equipped with the correct type
of undamaged sleeving, where required.
(17) Lacing should be as specified in
paragraph 3-12.
3-7
Figure 3-12. Crimping floated shield termination.
Figure 3-13. Insulated, non-insulated, and flag terminal crimps.
Figure 3-14. Crimping completed ferrule assembly.
3-8
TM 750-245-4
Figure 3-15. HYRING crimping procedure.
3-9
TM 750-245-4
Figure 3-16. Crimping insulated conductors.
3-10
TM 750-245-4
Figure 3-17. Equal spacing.
Figure 3-22. Single lock stitch completed.
Figure 3-18. Vibration bend.
Figure 3-23. Double lock stitch.
Figure 3-19. Clove hitch and square knot.
Figure 3-20. Running stitch.
Figure 3-24. Double lock stitch completed.
Figure 3-21. Single lock stitch method.
3-11
TM 750-245-4
Table 3-1. Stitch Spacing
Lacing intervals
inches, approximate
1/2 inch or less
1 inch
Larger diameter
Cable or harness
diameter
3/4 to 1 1/2
2
3
Figure 3-25. Serve at point of origin.
Figure 3-26. Serve method of tying.
Figure 3-28. Service loop.
Figure 3-27. Spot tie.
3-12
TM 750-245-4
Section IV. RF CABLES AND WAVE GUIDES
surface can effect the electrical characteristics and
make the part unserviceable. Flexible wave guides
should be handled carefully to prevent bending beyond
the required limit. Final inspection of wave guides
should accomplish the following.
a. Rigid Wave Guides. Dimensions are critical.
Inspect the interior as well as the exterior surfaces for
dents, corrosion, dirt or moisture. Do not handle interior,
as moisture from the skin may deposit acid on the
surface which will cause corrosion. If surfaces are found
to be satisfactory, cover the wave guide opening with a
moisture proof cover and store in a safe, dry place.
b. Flexible Wave Guides. Handle carefully during
inspection. Do not bend beyond usual extension. Do
not twist. Inspect interior surfaces for chips, dents,
corrosion, dirt, or moisture.
Examine the exterior
surfaces for blisters, tears, cracks, or any areas of
nonadherence to the jacket. Cover open area with a
moisture proof cover and place in a safe, dry area in a
relaxed position.
3-14. General
The inspection of rf cables and wave guides is of the
utmost importance.
The inspector should become
familiar with the complete repair procedures of rf cables
before he can properly inspect. The repair of wave
guides is restricted and usually requires only inspection
and cleaning.
3-15. RF Cables
The inspector should perform in-process inspections of
rf cable repairs. Figures 3-29 through 3-32 are included
to show proper repair procedures. During a final
inspection the inspector can remove the locknut or
clamp nut securing the connector body. He can then
remove the body and determine if the repair has been
done properly.
3-16. Wave Guides
Wave guides are fabricated of tubular or rectangular
metal. Dimensions are critical. Damage to the interior
3-13
TM 750-245-4
Figure 3-29. Termination procedures coaxial cable, using series N connectors.
3-14
TM 750-245-4
Figure 3-30. Coaxial termination using RG and 71/U connectors.
3-15
TM 750-245-4
Figure 3-31. Coaxial termination procedure using improved series BNC connectors.
3-16
TM 750-245-4
Figure 3-32. Finishing and termination of coaxial connector to coaxial fitting.
3-17
TM 750-245-4
Section V. PLUGS AND JACK ASSEMBLIES
3-17. General
Plugs and jack assemblies are the beginning and end of
electrical and electronic chassis. Proper input and
output signals or voltages are of the utmost importance
in equipment operation.
c. Bent and broken keys.
d. Moisture, corrosion, or any other contamination
which would affect equipment operation.
e. Potting to insure a firm smooth texture is
evidence of moisture.
f. Broken or defective attaching hardware securing
plugs and jacks to chassis.
g. Proper identification, stenciling, labeling, etc., as
required.
3-18. Inspection Criteria
The inspector should inspect all plugs and jacks for the
following:
a. Bent, Broken, or misalinement of pins and
contacts.
b. Warped outer shells.
Section VI. SERVO MECHANISMS
3-19. General
A servo mechanism is a power driven mechanism that
supplements a primary control. It tends to position an
object in accordance with the command given by an
arbitrarily varying position indicator capable of supplying
only a small amount of power.
Its operation is
dependent upon the difference between the actual
position of the object and the desired position.
b. Painted Surfaces.
(1) Smooth
(2) Without scratches
(3) Chipped surfaces
c. Gear Teeth. Coated lightly with grease.
d. Gear Train.
(1) Binding of the gears
(2) Excessive play
e. Gear Stops and Dials. For correct alinement.
f. Spur Gears. To insure that all mating spur
gears are alined.
g. Loose wiring, bad solder joints, damaged parts.
h. Variable Resistor. Insure that resistor is filled
with oil. when required.
3-20. In-Process Inspection (Visual)
Visually inspect the servo for obvious damage and
defects such as missing parts, loose wiring, broken
connectors, broken, chipped, or burned gear teeth, and
corrosion on machined surfaces.
3-21. Final Inspection
a. Machined Surfaces.
(1) Smooth
(2) Unmarked
3-22. Identification
Insure that all markings and stampings are legible.
Touch up and restore all markings and stampings.
Section VII. BATTERIES
3-23. General
The types of batteries presently in the Army inventory
are lead acid storage, nickel cadmium storage, dry and
thermal. The lead acid battery has an electrolyte of
sulfuric acid whose specific gravity varies with the
amount of charge in the battery. The nickel cadmium
type has an electrolyte of sodium hydroxide whose
specific gravity does not vary. Dry batteries and thermal
batteries are both sealed and require no maintenance
other than cleaning. Repair is authorized only on nickel
cadmium batteries.
Inspection will cover general
condition and serviceability.
3-24. Electrolyte
The surface of the liquid should be up to indicated level.
Add only distilled water and do not overfill. Filler caps
should be replaced.
3-25. Terminals
Terminals should be free of corrosion. Storage battery
terminals may be cleaned with an alkaline solution or
water. Corroded terminals of dry and thermal batteries
may indicate leakage. Check for broken cases.
3-26. Shelf Life
The permissible shelf life of dry and thermal batteries
should be indicated. Check for expiration.
3-18
TM 750-245-4
3-28. Inspection
Batteries shall be of the correct voltage and current.
The case shall not be cracked, leaking, or otherwise
damaged. Terminals shall not be corroded or loose.
Batteries must be shipped dry with a tag for activation.
3-27. Test
A test should be performed in accordance with
applicable TM's. Batteries must be under load when
testing. Do not test thermal batteries.
Section VIII. MISCELLANEOUS ITEMS
3-29. General
This section covers inspection of miscellaneous items
not covered by other sections of this chapter.
j. Assure that tube shields are the heat dissipating
type where applicable.
3-32. Switches and Controls
Inspect all switches and controls for the following:
a. Selector switch operation should be correct at
all positions.
b. Switches should be securely installed
c. Knobs or levers should be securely attached to
shafts.
d. Seating should be positive in all detent
positions.
e. Terminal connections should be properly
soldered or secured with terminal screws.
f. Contacts should not be dirty, burned, pitted,
welded, carbonized, or have contact resistance.
g. Micro-switch actuators should not bind.
h. Push switches should depress easily and return
to original position when released.
i. Push-pull switch (interlock) plungers should
depress easily and return to original position when
released.
j. Plunger should pull out and remain but return
easily to original position when depressed.
k. Insulators, wafers, and separators should not be
dirty, chipped, cracked, or broken.
I. Knob pointer should aline with position index.
m. Switch should turn easily to all positions.
n. Check that thermostatic switch operates
properly and cycles at specified temperature per
respective drawing.
o. Toggle switch boot should not be cracked,
torn, ripped, or rotted.
p. Toggle switch should be mounted in proper
position.
q. Momentary contact switches should return to the
original position when released.
3-30. Electrical Motors
Inspect all motors for the following:
a. The armature shaft should be straight and not
undersized.
b. The armature lamination and iron stakes should
not be loose.
c. Shaft splines should be free of cracks and
splinting and firmly installed.
d. Conductors should have no cuts, cracks,
abraded areas, fraying, corrosion, or evidence of
overheating.
e. Winding should be suitably impregnated with
varnish unless otherwise specified and there shall be no
flowing, cracking, or burnt odors.
f. There should be no evidence of motor running
hot or overheating.
g. Brushes securely installed and not broken,
cracked, or chipped, or worn beyond useable limits.
h. Motor should operate without excessive noise
and vibration.
i. If shock mounted, the mounts should be
serviceable.
3-31. Electronic Tubes
Inspect all tube assemblies for the following:
a. Radioactive electron tubes should be handled in
respective drawing.
b. Envelopes should not be cracked, broken, or
loose in base.
c. Pins should not be corroded, bent, or broken.
d. Tubes must be of the correct type, securely
seated, and firmly clamped in sockets.
e. Cathode ray tubes should have no burn spots,
or clusters of small burn spots greater than 1/4 inch in
diameter where normal presentation is obscured.
f. Keys should not be broken.
g. Tube clips should not be loose, cracked,
chipped, or broken.
h. Tube sockets should not be cracked, chipped,
broken, loose, or have any broken terminals.
i. Tube shields, clamps, retainers should not be
bent, broken, loose, or missing.
3-33. Transformers
Inspect all transformers for the following:
a. Transformers should be securely installed.
b. There should be no indications of overheating.
c. Windings should not be rough, loose, or broken.
d. Brushes (variable transformers) should be
securely installed and not broken, cracked, chipped, or
excessively worn.
3-19
TM 750-245-4
identification, proper color codes, missing parts,
damage, overheating, proper insulation, dirty or burned
contacts, contamination and possible shorting condition.
e. Brushes (variable transformers) should bear
firmly on windings along entire brush path and not
extend off ends of winding.
f. Markings should be clear and legible.
3-35. Fuses
Inspect fuses to insure that they are of the correct
voltage, current, and characteristic rating as shown in
table B-8 located in appendix B.
3-34. Assembly Components and Circuit Boards
Inspect capacitors, resistors, transistors, diodes, coils,
relays, miniature modules, circuit boards, etc., for proper
installation, broken or damaged leads, legible
3-20
TM 750-245-4
CHAPTER 4
MECHANICAL EQUIPMENT
4-5. Unknown Tap Drill Diameters
The diameters of tap drills can be found by the formula
D= T-0.75x2d in which D = drill diameter, T = diameter
of tap or thread, and d = depth of thread. The depth of
thread for various numbers of threads per inch and
thread forms, are given in various tables in appropriate
mechanical handbooks. The diameter obtained by the
above formula allows for a thread having 75 percent of
the standard depth which is sufficient for general work.
The formula applies to the American (National) thread
form. The diameter of the tap drill should not be smaller
than is necessary to give the required strength of thread,
as every decrease of even 0.001 inch in diameter of the
tap drill materially increases the power required for
tapping and the percentage of broken taps.
4-1. Introduction
This discussion of mechanical equipment is necessarily
limited. The basic information and theory required by
the inspector is presented; however, the breadth of the
subject does not permit a detailed listing of all attaching
hardware and attendant inspection procedures.
Mechanical equipment is designed to perform a function
at the least cost and with a minimum of required
maintenance during the life cycle of the item. The best
reliability and operation must be built into the item.
Missile equipment must have as near 100 percent
reliability as possible. Therefore, the best inspection
obtainable is required.
4-2. Attaching Hardware
Attaching hardware for the equipment is subjected to:
a. Sever stresses
b. Shock
c. Corrosion
d. Contraction and expansion of metals
e. Warpage
f. Temperature changes
g. Atmospheric conditions
h. Shelf life
4-6. Simplified Rule for Tap Drill Diameter
If a table of tap drill sizes is not at hand, the following
rule may be used: Rule-To find the tap drill diameter in
inches, subtract from the outside diameter of the tap an
amount equal to one divided by the number of threads
per inch. In the practical application of this rule, the
nearest commercial drill size is always used.
4-7. Thread Gage Tolerances
Gage tolerances for the four classes of American
Standard screw thread fits are designated as W, X, and
Y tolerances (table 4-1 and 4-2). These tolerances are
applicable to the National Coarse (NC) and National
Fine (NF) Series, and to comparable diameters and
pitches. The recommended uses for W, X, and Y gage
tolerances are as follows:
a. Working Gages. For classes 1 and 2 fits, use Y
tolerances; for class 3, use X tolerances; for class 4, use
W tolerances.
b. Inspection Gages. Recommended uses are the
same as given under working gages.
c. Setting Gages. These thread-plug gages are
used in adjusting thread-ring gages, thread-snap gages,
or other thread comparators. For classes 1 and 2 fits,
use X tolerances; for class 3 fit, use W or X tolerances;
for class 4, use W tolerances.
4-3. Tapping and Thread Cutting - General
Tapping troubles are often caused by using tap drills
that are too small in diameter.
For ordinary
manufacturing, not more than 75 or 80 percent of the
standard thread depth is necessary, and for some
classes of work, not more than 50 percent is required.
Tap drill sizes, especially for machine screws, should be
varied according to the material to be tapped and the
depth of the tapped hole.
4-4. Types of Holes (Tapping)
Soft material, such as copper, soft iron, drawn
aluminum, etc., should have a larger hole for the tap
than hard crystalline materials such as cast metals.
When tapping soft materials, if the hole is too small, the
threads will be torn off to some extent, thus actually
decreasing the effective thread depth as compared to
what it would be if the tap drill had been of larger
diameter, but if the hole is drilled rather large, -when
tapping tenacious materials, the metal at the top of the
thread is drawn somewhat, thereby increasing the
depths of the threads. This is more likely to occur after
the keen edge of the tap has been slightly dulled by use.
4-8. "GO" Gages for Screw Threads (Fig. 4-1)
A "Go" gage should check simultaneously as many
elements as possible, whereas a "Not Go" gage usually
checks one element only. A "Go" gage
4-1
TM 750-245-4
Table 4-1. American Standard Thread Gage Tolerances
Threads
per
inch
80
72
64
56
48
44
40
36
32
28
24
20
18
16
14
13
12
11
10
9
8
7
6
5
4 1/2
4
W
gages
....
....
....
....
....
....
....
....
....
.0001
.0001
.0001
.0001
.0001
.00015
.00015
.00015
.00015
.0002
.0002
.0002
.00025
.00025
.00025
.0003
.0003
Pitch diameter tolerances
X
gages
Y gages
From
To
.0002
.0001
.0003
.0002
.0001
.0003
.0002
.0001
.0003
.0002
.0001
.0004
.0002
.0001
.0004
.0002
.0001
.0004
.0002
.0001
.0004
.0002
.0001
.0004
.0003
.0001
.0004
.0003
.0002
.0005
.0003
.0002
.0005
.0003
.0002
.0005
.0003
.0002
.0005
.0003
.0002
.0006
.0003
.0002
.0006
.0003
.0002
.0006
.0003
.0002
.0006
.0003
.0002
.0006
.0003
.0002
.0006
.0003
.0002
.0007
.0004
.0002
.0007
.0004
.0002
.0007
.0004
.0003
.0008
.0004
.0003
.0008
.0004
.0003
.0008
.0004
.0003
.0009
Major or minor
diam. tolerances
W
X and Y
....
.0003
....
.0003
....
.0003
....
.0004
....
.0004
....
.0004
....
.0004
....
.0004
....
.0004
.0005
.0005
.0005
.0005
.0005
.0005
.0005
.0005
.0006
.0006
.0006
.0006
.0006
.0006
.0006
.0006
.0006
.0006
.0006
.0006
.0007
.0007
.0007
.0007
.0007
.0007
.0008
.0008
.0008
.0008
.0008
.0008
.0009
.0009
W
....
....
....
....
....
....
....
....
....
.00015
.00015
.00015
.00015
.00015
.0002
.0002
.0002
.0002
.00025
.00025
.00025
.0003
.0003
.0003
.0003
.0003
Lead*
tolerances
X and Y
.0002
.0002
.0002
.0002
.0002
.0002
.0002
.0002
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0003
.0004
.0004
.0004
.0004
.0004
.0004
*Allowable variation in lead between any two threads not farther apart than the standard length of engagement, which is
equal to the basic major diameter.
Threads
per
inch
80
72
64
56
48
44
40
36
32
28
24
20
18
W
gage
....
....
....
....
....
....
....
....
....
8'
8'
8'
8'
Table 4-2. Tolerances on Half Angle of Thread, Minutes
Threads
X
Y
per
W
X
gage
gage
inch
gage
gage
30'
45'
16
8'
10'
30'
45'
14
6'
10'
30'
45'
13
6'
10'
30'
45'
12
6'
10'
30'
45'
11
6'
10'
20'
30'
10
5'
10'
20'
30'
9
5'
10’
20'
30'
8
5'
5'
15'
20'
7
4'
5'
15'
20'
6
4'
5'
15'
20'
5
4'
5'
15'
15'
4 1/2
4'
5'
10'
15'
4
4'
5'
4-2
Y
gage
15'
15'
15'
10'
10'
10'
10'
5’
5'
5'
5'
5'
5'
TM 750-245-4
checks the maximum limit of a threaded plug and the
minimum limit of the threaded hole.
a. Pitch Diameter. The pitch diameter of W and X
"Go" plug gages is the same as the minimum pitch
diameter of the threaded hole or nut. The Tolerance is
plus for plugs. The pitch diameter of the W and X "Go"
ring gages is the same as the maximum pitch diameter
of the screw. The tolerance is minus for rings.
b. Major and Minor Diameters.
The major
diameter of the "Go" plug gage is the same as the basic
major diameter, with a plus tolerance. The minor
diameter of the "Go" ring gage is the same as the
minimum minor diameter of the nut or tapped hole, with
a minus tolerance.
minimum pitch diameter of the screw. The tolerance is
plus but may be minus for the reason given in the
preceding subparagraph.
4-10. Thread Form on Gages
Figure 4-1 shows approved thread forms for both plug
and ring gages. The crest of the thread on "Not Go"
plug and ring gages is partly removed to insure proper
contact. There is also a clearance groove at the root of
"Not Go" plug and ring gages to insure pitch diameter
contact. The "Go" plug and ring gages may have
clearance grooves at the roots to facilitate grinding and
lapping.
4-11. Truncated Setting Plugs
a. The major diameter of the full portion of the
"Go" setting plug is that of a full American National
form, based on maximum pitch diameter of the screw.
The tolerance is plus. The major diameter of the
Truncated portion of the "Go" setting plug is that of a full
American National form minus one-third the basic
thread depth with a minus tolerance.
b. The major diameter of the full portion of the
"Not Go" setting plug is the same as that of the "Go"
plug of the same nominal size, except that the
truncation from a theoretical vee should not be less than
0.058 times pitch. The latter condition might arise in the
case of fine pitches and especially wide tolerances. The
tolerance is minus. The major diameter of the truncated
portion of the "Not Go" setting plug is that of a full
American National form minus one-third the basic
thread depth, with a minus tolerance.
Figure 4-1. Screw thread check.
4-9. "Not Go" Gages for Screw Threads (Fig. 4-1)
A "Not Go" thread gage which checks the pitch diameter
only, usually meets practical requirements. The "Not
Go" gage checks the minimum limit of a threaded plug
and the maximum limit of a threaded hole.
a. Pitch Diameter Plug Gage. The pitch diameter
of a "Not Go" plug gage equals the maximum pitch
diameter of the threaded hole or nut. The tolerance is
minus but may be plus. All gages used for the
production of screw threads, and "Go" gages for
inspection, should be within the extreme limits of the
product. However, to avoid needless controversy about
parts close to "Not Go" limits because of possible small
differences in gage sizes, the pitch diameter tolerances
on all "Not Go" gages used for final inspection and for
inspection of purchased products, may be outside of the
product limits is specially authorized.
b. Pitch Diameter Ring Gage. The pitch diameter
of the "Not Go" thread-ring gage is the same as the
4-12. Inserts
a. The inspector should familiarize himself with the
repair procedures, as in-process inspection should be
performed to insure a good insert installation. Refer to
the system documentation to determine if such repairs
are authorized and the number of times the insert can
be replaced.
b. There are various types of inserts which can be
used to repair components which have attaching hole
threads stripped. New hole preparation as shown in
figure 4-2 is primarily the same for all types of insert
installation.
4-13. Swaging Type Insert Installation (fig. 4-3)
The installation of swaging type inserts requires special
tools. A drive wrench is used to install the insert into the
tapped hole. After the insert is installed to the proper
depth a swage tool is then used to lock the insert in
place.
4-3
TM 750-245-4
4-14. Key Type Insert Installation
The installation of key type inserts is very simple and
can be accomplished without special tools. After hole
preparation (fig. 4-2) or old key insert removal (fig. 4-4)
screw the new key insert (fig. 4-5) to a depth of 0.010 to
0.030 below the surface. Drive the keys down (fig. 4-6)
to set and lock the insert.
4-15. Blind Nut Assemblies (Fig. 4-6)
The inspector will have to perform an in-process
inspection of blind nut installations because in most
cases they cannot be inspected after repair. Refer to
figure 4-6 which shows the proper procedure for
installation of blind nuts.
4-16. Hardware Inspection
All hardware shall be of the proper size, type, shape,
length, and thread. There shall be no burrs, corrosion or
physical damage. Washers shall have correct pileup.
Screws shall protrude at least one complete thread from
the surface of the hex or clinch nut. Screws shall not
protrude more than two complete threads from the
surface of the hex or clinch nut when there is a
possibility of shorting, mechanical interference, or safety
hazard.
a. Threaded Components (Bolts, Screws, and
Nuts).
(1) Threads shall not be crossed or stripped.
(2) Bolt shanks shall not be galled.
Figure 4-2. New hole preparation.
Figure 4-3. Swaging type insert installation.
4-4
TM 750-245-4
Figure 4-4. Removal of key type insert.
Figure 4-5. Key type insert installation
Figure 4-6. Driving the keys down.
Figure 4-7. Blind nut assembly installation.
4-5
TM 750-245-4
spots, scoring, galling, and other surface imperfections
visible to the normal unaided eye.
(2) All bearings shall be of proper type and
size, properly lubricated, and properly installed.
i. Gears, Belts, and Pulleys.
(1) Gears
(a) Teeth shall not be burred, chipped,
cracked, galled, deformed, or broken.
(b) Lubrication shall be of the proper
type and quantity.
(c) Nylon gears shall be replaced when
required. Repair shall not be attempted.
(d) Disassembled gears (not mounted
on shafts) shall be checked for proper pitch diameter,
total composite error, and tooth-to-tooth error using a
rolling fixture, master gear set, and super micrometer.
(e) Gears shall be in alinement and
mesh properly.
(f) Shielded bearings shall be replaced
when required. No repair shall be attempted..
(g) There shall be no excessive noise
or rough motion.
(h) Teeth of antibacklash gears shall be
properly alined.
(i) When disassembled, gears shall be
coded for replacement in same assembly.
(2) Belts
(a) Shall not be cut or cracked.
(b) Must be pliable.
(c) No visible tears at joining seam.
(d) Installed belts must be taut but not
tight.
(e) Installed as pairs when required.
(3) Pulleys
(a) Shall not be burred, chipped,
cracked, galled, deformed, or broken.
(b) Groove shall be free of all foreign
matter.
(3) Bolt heads shall not be worn or damaged.
(4) Threads shall be properly lubricated, if
required.
b. Inserts (Helicoil or Kelox).
(1) Inserts or base metal shall not be
corroded.
(2) Inserts shall not be cracked, have proper
application, and be installed properly.
(3) Inspect keys of key type inserts to insure
that they are in place and below the surface of the
parent material.
c. Blind Nuts.
(1) Inspect sleeve assembly to insure that the
expander has been set properly as shown in figure 4-6.
(2) Inspect final assembly to insure that bolt
can be tightened without rotation of the expander which
should be set into the sleeve.
d. Quick Acting Fasteners.
(1) Mechanical operation and alinement shall
be correct.
(2) Hardware shall not be loose, missing, or
damaged.
(3) Lubrication shall be of correct type and
quantity.
e. Rivets.
(1) Assure correct size rivet is used.
(2) Assure that head is flush against metal
and that rivet is tight.
f. Safety Wiring.
(1) Assure that safety wiring is accomplished
in accordance with requirements contained on pertinent
drawing or technical manual.
(2) Assure that only new wire is used.
g. Shims.
(1) Assure that shims are only used where
authorized.
(2) Assure that shims are installed securely.
h. Bearings.
(1) Running surfaces shall be characteristic
of a lapping or polishing process and free of tool marks,
chatter, waves, scratches, gouges, nicks, pits, soft
4-6
TM 750-245-4
CHAPTER 5
HYDRAULIC AND PNEUMATIC EQUIPMENT
Section I. INTRODUCTION
5-1. General
This chapter orients the inspector to varied inspection
requirements of hydraulic and pneumatic assemblies
and piece parts. Certain items such as o-rings, gaskets,
and flarings require in-process inspection. These items
normally cannot be inspected during final inspection.
the hose is adequately "anchored" to prevent whiplash in
the event of failure.
d. Equipment used in cleaning and testing
processes shall be free from grease, lint, dust, and other
foreign matter. Fluid containers and test equipment
should be tested regularly for excessive contamination.
5-2. Precautions During Testing
a. Generally, pneumatics involve the use of high
pressure air. Therefore, the testing of any component
which is subjected to high-pressure must be pressure
tested in an approved barricaded area following all
established safety precautions.
b. Hands, or other parts of the body, should never
be used in high-pressure testing to "feel" for pressure
leaks, especially in hoses. These type leaks may cause
serious injury to the operating personnel. Leaks of this
type should be checked by the use of a soap and water
solution or submerged bath.
c. When testing high-pressure hoses, insure that
5-3. Inspection or Test
a. During final inspection, insure that all parts are
properly assembled and functioning according to
technical manual requirements. This includes pumps,
gages, reservoirs, and valves.
b. All air and gas receivers subject to a working
pressure in excess of 500 psi will be hydrostatically
tested to a pressure at least 1.5 times the maximum
working pressure. All receivers in use will be given a
hydrostatic test every 24 months or at anytime a
receiver shows any evidence of bad dents, corroded
area, leakage, or other conditions that indicate
weakness which might render the receiver unsafe.
Section II. HYDRAULIC COMPONENTS
5-6. Final Inspection
a. Operational Test.
(1) Component under test will be connected
as prescribed in the hydraulic test stand procedures and
subjected to tests specified in the technical manual for
the item being tested.
(2) Surfaces must pass a wipe test to
supplement visual inspection. Surfaces shall be free, in
addition to the above, from fingerprints, perspiration, or
other acid or alkaline residues.
(3) During operation, inspection shall be
made to determine that various functions are
accomplished satisfactorily, the movement of all
components is 'smooth, and all tubing, fitting joints, and
external seals are free from leaks.
b. Visual Inspection.
(1) Lines and hoses.
(a) Cracks
(b) Dents
(c) Scratches
(d) Leaks
(e) Contamination
(f) Corrosion
5-4. General
Hydraulics is the science of applied pressure to a fluid
for emission of a working force in a closed system. Six
basic components make a complete working system
(reservoir, fluid, pump, pressure valve, directional valve,
and working component).
5-5. In-Process Inspection
a. Assemblies and parts shall be free from dirt,
corrosion, oil, grease, and similar foreign residues.
b. Whenever practicable, internal parts of
assemblies shall be thoroughly cleaned prior to
assembly.
c. Hand tools and other equipment used in
cleaning and testing processes shall be free from
grease, lint, dust, and other foreign matter. Fluid
containers and test equipment shall be tested regularly
for excessive contamination.
d. Insure that o-rings, gaskets, and seals have no
paint on any surface. Insure adequate shelf-life where
necessary.
Also, insure that o-rings are properly
installed and that back-up rings are used where needed.
5-1
TM 750-245-4
(2) Coupling nuts.
(a) Torqued
(b) Torque stripped
(3) Reservoirs.
(a) Fluid leakage
(b) Proper fluid level
(4) Flares for correct angle.
(5) B-nuts.
(a) Not cracked
(b) Damaged hex-heads
(6) Lines.
(a) Properly routed
(b) Secured
(7) Lines, units, and supports.
(a) Pits
(b) Corrosion
(c) Sharp corners
(d) Vibration
(e) Leaks
(8) Fitting joints and seals for leaks.
5-7. Identification
Component must be properly identified by stamping or
nameplate and, if possible, placed in a sealed plastic
container for on-the-shelf storage.
Section III. PNEUMATIC COMPONENTS
5-8. General
Pneumatics is a branch of mechanics that deals with the
mechanical properties of gases.
(2) Fittings and clamps.
(a) Securely mounted
(b) Machined surfaces free of burrs and
longitudinal marks
(c) Sealing surfaces-smooth
(d) Unmachined surfaces-cracks, laps,
seams
(3) Castings.
(a) Blow holes
(b) Porosity
(c) Cracks
(4) Welds.
(a) Pits
(b) Blisters
(c) Slivers
(d) Corrosion
(e) Excess flux
(5) Coupling nuts.
(a) Properly torqued
(b) Torque stripped
(6) Gages, safety valves, and unloaders.
Check for proper operation. Gages will not vary more
than two percent from normal operating pressure.
5-9. In-Process Inspection
Insure that only new precleaned o-rings and gaskets are
used. Cure dates shall be within specified tolerances.
5-10. Final Inspection
a. Operation Test.
(1) Hoses.
High-pressure hoses must
withstand 125 percent of the rated operating pressure
for a minimum of one minute without showing defects
(i.e., leaks, unequal expansion, cuts, or breaks).
(2) Receivers. All air receivers subject to a
working pressure in excess of 500 psi must be subjected
to hydrostatic test at least equal to one-and-one half
times the working pressure.
b. Visual Inspection.
(1) Hoses and covers.
(a) Cuts
(b) Cracks
(c) Checked
(d) Hardened
(e) Rotted
(f) Contaminated with dirt, grease, and
foreign objects.
5-11. Identification
Markings, warnings, and identifications shall be correct
and legible.
5-2
TM 750-245-4
CHAPTER 6
OPTICAL EQUIPMENT
only to provide a safer storage place for the instruments,
but to provide a central distribution point from which to
supply the instruments.
Always be sure that an
instrument is placed in its case in the proper position.
6-1. Introduction
Optical equipment used with missile systems normally
has a specific function and is separately identifiable,
such as theodolites and optical trackers. Due to this
specificity, detailed maintenance and inspection
instructions
are
usually
included
in
system
documentation. Accordingly, this chapter will treat the
inspection procedures in a general manner. Only visual
inspection procedures are presented. It is assumed that
the inspector has some knowledge of the optical
equipment applications and is properly aware of the
delicacy of the items and the importance of accuracy.
6-3. Visual Inspection
a. Optical Surfaces.
(1) Smears
(2) Fingerprints
(3) Chips
(4) Fractures
(5) Grayness
(6) Stains
(7) Coating
b. Paint.
(1) Chipped
(2) Loose
(3) Corrosion present
(4) Bare spots
c. Rubber Eyeshield.
(1) Securely molded
(2) Cracks
(3) Damage
(4) Deterioration
(5) Mounted properly
d. Data Plates.
(1) Clearly defined
(2) Mounting adequate
(3) Condition good
(4) Legible
e. Eyepiece.
(1) Dirt
(2) Scratches
(3) Smears
(4) Gouges
(5) Condensation
(6) Fungus
(7) Chips
(8) Fractures
(9) Cement separation
f. Sealing.
(1) Leaks
(2) Openings
g. Illuminating Windows.
(1) Broken windows
(2) Cracked
6-2. Care and Handling of Optical Instruments
a. The useful life and continued accuracy of optical
instruments and accessories depends upon the extent to
which they are properly cared for and handled. An
instrument inspector must realize this fact and acquaint
himself with recommended practices pertaining to each
instrument and accessory he uses.
b. When transporting optical instruments, extreme
caution should be exercised to prevent damage. If a
mobile unit is used, it should be especially equipped for
that purpose. Upon arrival at a destination, if optical
instruments are not be used immediately, they should
be stored in such a manner as to prevent their falling,
bumping, or jarring accidentally. They should remain in
their cases until needed.
c. Always be sure that an instrument is properly
mounted and secured but never overtighten a clamping
screw as this could damage the instrument. Be sure the
proper clamping screw is loose before the instrument is
to be revolved about an axis. It should also be noted
that leveling screws need not be overtightened. Snug
tension is sufficient.
d. Always remove an instrument from its stand
before moving the instrument or the instrument stand to
a new location. Failure to adhere to this procedure
could result in serious damage to the instruments due to
excessive bumps and vibrations. Protection should be
provided for instruments set up in aisles or where traffic
is excessive by setting up barricades or guard rails.
Instruments mounted on stands should be protected with
plastic covers when not in use. Never leave an optical
instrument with a lens pointing upward without a
protective cover over the objective end of the telescope
as foreign matter could collect and damage the lens.
e. After optical instruments have been used in the
shop, return them to their proper place. This is done not
6-1
TM 750-245-4
(2) Distinct
l. Level Vials.
(1) Cracked
(2) Broken
(3) Loose
(4) Cover missing or broken
(5) Bubble appears properly
m. Instrument Lights.
(1) Case intact and undamaged
(2) Switch functions properly
(3) Lamp operates
(4) Lucite windows undamaged and clear
h. Machined Surfaces.
(1) Free of nicks
(2) Burrs
i. Housings.
(1) Damage
(2) Cracks
(3) Dents
j. Knobs and Handles.
(1) Binding
(2) Roughness
k. Graduations and Numbers.
(1) Clear
6-2
TM 750-245-4
CHAPTER 7
SOLDERING
Section I. INTRODUCTION
electrical connections. Material requirements and tools
are provided in system TM's.
7-1. General
a. This chapter contains requirements for soldering
of electrical and electronic equipment.
This information has been developed to increase the
reliability of equipment undergoing repairs at direct
support and general support shops. These concepts
have proven to be adequate for all fielded equipment.
Harness layout, lacing, crimping of solderless
connectors, and terminations are contained in chapter 3,
electrical and electronic equipment.
b. This chapter presents the instructions for
inspections of soldering to obtain high reliability
7-2. Inspection Requirements
Inspection requirements will hold true only if the
inspector has a knowledge of proper soldering
techniques. He must also have a knowledge of proper
tools and materials available. The following sections
should provide him with adequate inspection procedures
and acceptance criteria to evaluate and determine if
proper soldering repairs have been accomplished.
Section II. INSPECTION PROCEDURE
should be inspected in accordance
with paragraph 7-3.
7-3. General
Many electrical chassis in the field were produced under
standards that are no longer used for missile system
production. The inspector must know and recognize
these differences to preclude unnecessary rejection and
rework of chassis. These differences are:
a. Wraps of conductor 270 degrees to 360 degrees
around turret terminal were permitted, present
requirements are 180 degrees, but not more than 360
degrees except multiple adjacent terminals.
b. Bare copper ends were permitted; now
conductor ends must be covered by solder.
c. Nicks on leads were permitted; padded tools
must now be used to form leads.
d. Slack in leads and vibration bends for mounting
of components were not required; these are now
required.
e. Insulation clearance from the solder joint was
not specified; see paragraph 7-10f.
7-5. Mechanical
Mechanical check of a solder point is acceptable only
when required to supplement a visual inspection. This
must be limited to a minor movement of component
leads using only padded pliers or wooden soldering aid.
Care must be taken not to fracture delicate solder joints
or to break the component leads.
7-6. Surveillance
A surveillance program should be initiated jointly by the
repair shop and QC inspection units. The primary
purpose of the surveillance program is to establish the
standard operating procedures and standard inspection
procedures to assure that repaired materials will meet
the designated purpose for tactical operations. The
following areas should be included in the surveillance
program, but may vary depending upon: DS/ GS
mission
assignments,
tactical
situation,
and
geographical location.
a. Housekeeping.
(1) Cleanliness of work area.
(2) Lighting of work area.
(3) Arrangement of work benches to test
equipment.
b. Control of Tools.
(1) Correct tools to perform the specific
soldering function.
(2) Proper use of soldering tools.
7-4. Visual Inspection
All soldered connections shall be inspected for:
a. Adequate mechanical and solder application.
b. Cleanliness.
(1) Removal of rosin flux.
(2) Removal of solder splatter from adjacent
areas.
NOTE
Solder connections other than those
made by the DS/GS repairman
7-1
TM 750-245-4
7-8. Thoroughness of Inspections
Thoroughness of inspections will prevent unsatisfactory
equipment from being released from the maintenance
shop. The inspector must initiate the inspection at a
common point for soldering operations. The following is
offered to attain a standard level of workmanship:
a. Review the job order (DA Form 2407) to
determine which components were repaired or replaced.
Connections should meet the requirements of this
chapter.
b. All other solder connections should be
examined to determine adequacy.
(3) Periodic inspection of tools for proper
maintenance.
(4) Replacement of tools when worn beyond
established limits.
c. Control of Materials Used During Repair
Procedures.
(1) Only qualified products are to be used.
(2) Disposal of excess or unqualified
materials.
7-7. Workmanship Standards
Workmanship standards for soldering operations
encompass two areas:
a. The repairman should be trained in soldering
techniques.
b. Workmanship for the inspector is based upon
the inspector's knowledge of the equipment he is
inspecting and knowledge of inspection requirements.
7-9. Mechanical Connections
Table 7-1 lists some of the approved methods of making
mechanical connections prior to soldering.
Table 7-1. Mechanical Connections
Connector type
Illustration
Turret terminal wrap
Turret terminal multi-connection
7-2
TM 750-245-4
Table 7-1. Mechanical Connections - Continued
Connector type
Illustration
Double ended terminal
Bifurcated terminal side route single connection
7-3
TM 750-245-4
Table 7-1. Mechanical Connections - Continued
Connector type
Illustration
Bifurcated terminal multiple side route connections
Bifurcated terminal bottom route connection
7-4
TM 750-245-4
Table 7-1. Mechanical Connections - Continued
Connector type
Illustration
Bifurcated terminal top route connection.
Hook terminals
7-5
TM 750-245-4
Table 7-1. Mechanical Connections - Continued
Connector type
Illustration
Eye terminals
Feedthru terminal top termination
7-6
TM 750-245-4
Table 7-1. Mechanical Connections - Continued
Connector type
Illustration
Feedthru terminal bottom termination
Section III. ACCEPTANCE AND REJECTION CRITERIA
7-10. Acceptance Criteria
All soldered connections shall be inspected for
conformance to the following conditions:
a. Solder Connection. The solder connection shall
have a smooth, bright appearance, without porosity,
cracks, pits that bottom out, or surface strain lines.
Solder shall cover the top of the conductor wire and
concave fillet should be observed between the lower
half of the conductor wire and the terminal. There shall
be no foreign material or threads of insulation
embedded in the solder.
b. Residual Flux. Each soldered connection shall
be inspected to determine that all flux has been
removed.
c. Excessive Solder. Beads or peaks of solder
shall not project from the terminal and no solder shall
exist as runs on the outside of the terminal. There shall
be no solder splatter on the adjacent components or
surfaces.
d. Cold Solder Joint. The solder shall adhere
firmly and smoothly to the parts joined. The joint shall
not be chalky in appearance, laking metallic luster, nor
shall it have a rough, gritty, piled-up surface.
e. Rosin Joint. Flux shall not be trapped in the
solder joint. The conductor wire in the joint shall not
move under light probing pressure.
f. Insulation. The insulation shall not be charred,
frayed, split, or pinched through exposing the conductor
wire. Slight discoloration of insulation shall not be
considered cause for rejection. Insulation clearance
from the solder joint shall be as shown in table 7-2.
g. Capillary Action (Wicking).
Wick length of
solder on the wire strands shall be visible and shall not
extend into the insulation.
h. Conductor Wire and Component Lead Tension.
All conductor wires and component leads going to a
soldered connection shall have a slack in the form of an
arc or gradual bend. Solder(d components shall not be
in electrical contact with adjacent circuitry; or other
components.
i. Excessive Heat. Components and insulation
shall not show evidence of excessive heat caused by
improper soldering or electrical shorts.
j. Multiple Terminations.
The number of
connections per terminal shall be in accordance with
system requirements. Each conductor wire shall be
adjacent to the surface of the terminal, not overlapping
another. Multiple connections on terminals shall be as
follows:
(1) Turret terminals. The wire shall l)e in
contact with the terminal for the full curvature of the
wrap and in no case wrapped less than 180
7-7
TM 750-245-4
Table 7-2. Insulation Clearance for Solder Joints
Wire
diameter
Insulation
Minimum
Clearance
maximum
32 to 24
22 to 12
10 or larger
1/32
1/32
1/32
3 x OD
2 x OD
1 x OD
degrees or more than 360 degrees. Where three or
more terminals in a row require a continuous jumper, a
solid bus may be wrapped 360 degrees, and continued
from terminal to terminal. The first wire on each
terminal shall be placed parallel to the header nearest
the terminal mounting surface. Each additional wire
shall be placed next thereto, continuing outward from
the terminal mounting surface.
Maximum spacing
between wires and between wire and header is
recommended. There shall be no overlapping of wires.
Wrap may be clockwise or counter-clockwise; however,
on multiple connections all wraps must be in the same
direction, unless required by design limitations. When
soldering the second joint on double ended terminals,
precaution shall be taken to prevent remelt and fracture
of the first joint.
(2) Slotted or bifurcated terminals. Order of
preferred terminations:
(a) Side route connection. The wire
shall enter the mounting slot at a right angle and be
terminated with a 90-120 degree bend. A bend of 180
degrees is permitted when design requires mechanical
holding prior to soldering. In no instance shall the
conductor extend beyond the outside diameter of the
terminal, except for the point of entry. The direction of
the 90-degree bend on each additional wire shall
alternate.
Maximum space between wires is
recommended.
(b) Bottom route connection. The wire
shall terminate with a 90-degree bend.
(c) Top route connection. The wire
shall extend the full length of the terminal forks. When
the ratio of slot size to wire size is greater than 1: 1, the
wire should be accompanied by a tinned filler wire
during the soldering operation to help hold the wire in
position, or the wire can be doubled back. A large wire
which fills the slot will require only solder fillets for
retention. Multiple top route connections shall not be
used unless specified in Department of the Army
publications.
(3) Hook or perforated terminals. The wire
shall be attached to the hook or perforated terminal by
forming the tinned wire to at least 90-degrees angle.
Perforated terminals to which wire sizes ACG 16 or
larger are to be attached may be connected straight
through.
(4) Feed-through terminals. The terminating
end of a wire inserted through a feed-through terminal
shall be hooked over the lip of the terminal not less than
one-sixteenth inch. Not less than one-sixteenth inch of
the connection hook shall be soldered tangent to the
terminal.
(5) Printed circuit terminating. Components
shall be installed opposite to the side to be soldered.
Leads shall be bent flat to the pad and along the
conductor surface.
Components having pin type
connections shall be mounted with pins extending
straight through the printed circuit board.
When
component lead wire diameter, length, or composition
prevent bending, or when specified in Department of the
Army publications, the lead shall be treated as a pin
type. "Double sided printed circuit boards employing
eyelets for the interfacial circuit connections shall have
the eyelets soldered to the pad on both sides of the
board as well as the usual mechanical bradding. Double
sided printed circuit boards employing plated through
holes for interfacial circuit connections shall have a
continuous plug of solder through the hole. The hole
pads on both sides of the board shall be completely
wetted by the solder 360 degrees around the periphery
of the hole."
7-11. Rejection Criteria
Evidence of any defects, including, but not limited to the
following, shall be cause for rejection:
a. Charring, burning, or other damage to
insulation.
b. Splattering of fluz or solder on adjacent
connections or components.
c. Solder points (peaks).
d. Pits, scars, or holes.
e. Excessive solder which obscures the connection
configuration.
f. Excessive wicking.
g. Loose leads or wires.
h. Cold solder connections.
i. Rosin solder connection.
j. Fractured solder connection.
k. Cut, nicked, stretched, scraped leads, or wires.
l. Unclean connection (e.g., lint, residue, flux,
solder, splash, dirt, etc.).
7-8
TM 750-245-4
allowed on system drawings and as permitted by
Department of the Army publications for system
material.
r. Plated through holes not filled with continuous
solder plug.
s. Pads connected by plated-through holes and
eyelets connecting pads on multi-layer boards or double
sided printed circuit boards show evidence of failure to
wet the metallic surfaces.
m. Dewetting. (Separation of printed circuit from
circuit board.)
n. Insufficient solder.
o. Visible bare primary conductor within the solder
joint area.
p. Clinched leads resulting in a reduction of the
required spacing between conductors.
q. Splicing of conductors is prohibited, except as
Section IV. COMPARISON STANDARDS
Table 7-3 shows a simulated comparison between good
and bad workmanship. The remaining tables show
actual repair procedures with applicable inspection
criteria.
7-12. General
This section provides a visual guide for inspection of
solder connectors.
These show the acceptable,
minimum acceptable, and reject inspection criteria.
Table 7-3. Workmanship
Indicator
Illustration
Cold or underheated solder joint
A. Solder has a chalky appearance, lacks metallic
luster, generally presents a rough, piled-up
appearance.
B. Solder has not bonded terminal and wire
together.
C. Solder coverage not complete.
D. Improper filleting indicating insufficient flowing
and watting action.
Improper soldering
7-9
TM 750-245-4
Table 7-3. Workmanship - Continued
Indicator
Illustration
Cross-section good solder joint
A. A minimum amount of solder shall cover the top
of the conductor.
B. Wire, solder and terminal must be completely
fused at this point and wire must be adjacent to
terminal.
C. Entire mass consisting of terminal, wire and
solder must be free of all foreign substances.
D. Conductor wire (copper).
E. Terminal or printed circuit (PC) pad.
F. Smooth solder contour and proper filleting
action indicating required flowing and wetting
action.
Cross-section tubular connection
A. Slight protrusion is acceptable at weep hole.
B. Fillet from all sides of the solder cup.
C. Excess solder. Any solder on the outside
surface should be a thin film only.
D. Excess insulation gap, conductor not to bottom
of cup.
E. No fillet.
7-10
TM 750-245-4
Table 7-3. Workmanship - Continued
Indicator
Illustration
Improper insulation
Vibration bends
7-11
TM 750-245-4
Table 7-3. Workmanship - Continued
Indicator
Illustration
Vibration bends
type of cup connector. The criteria is applicable to all
cup type connectors.
7-13. Insulation
Table 7-4 presents inspection criteria and references to
illustrations of insulation.
7-16. Solder Coverage-Printed Circuit
Table 7-7 presents inspection criteria for solder
coverage on printed circuit boards.
7-14. Stranded Conductors
Table 7-5 presents inspection criteria and reference to
illustrations covering stranded conductors.
7-17. Solder Coverage-Connector Pin
Table 7-8 presents inspection criteria for solder
coverage of pin type connection when used on printed
circuit boards.
7-15. Cup Connectors
Table 7-6 presents inspection criteria for all types of cup
connectors, the referenced illustrations show only one
7-12
TM 750-245-4
shown, solder coverage should be the same regardless
of routing.
7-18. Solder Coverage-Turret Terminals
Table 7-9 presents in-operation criteria for turret type
terminals.
7-20. Soldering of Components
Table 7-11 presents proper mounting, spacing an
soldering for installation of components in electronic
equipment.
7-19. Solder Coverage-Bifurcated Terminals
Table 7-10 presents inspection criteria for soldering
bifurcated terminals, only side route connections are
Table 7-4. Insulation
Inspection Criteria
Illustration
ACCEPTABLE
Insulation is unmarked
Exposed bare wire is held to a minimum
Trim is neat and even
MINIMUM ACCEPTABLE
Minor scorch marks on insulation
Trim is slightly irregular
Exposed wire is within tolerance with no sign of
wicking
REJECT
Insulation has been burned
Excess heat and solder has caused
Very bad connection - excess heat
Excess solder (lead not discernible)
Cold solder
Rosin entrapment
Lead not terminated at base of terminal
Lead extends outside of terminal
7-13
TM 750-245-4
Table 7-5. Stranded Conductors Inspection Criteria
Inspection criteria
Illustration
ACCEPTABLE
Joint is under no tension
Original lay or twist of the wire has been maintained
MINIMUM ACCEPTABLE
Diameter of loop is sufficient to avoid tension on
joint
Original lay or twist of the wire has been
maintained
Insulation rough
REJECT
Wire has been bent in a sharp right angle bend
causing strands to kink
Strands have been flared on terminal
Lead not terminated at base of terminal
Not cleaned properly
7-14
TM 750-245-4
Table 7-6. Cup Connectors
Inspection criteria
Illustration
ACCEPTABLE
Conductor is correct size for cup application
Solder completely fills the cup and follows the
contour of the cup entry slot
Strands visible
MINIMUM ACCEPTABLE
Conductor is maximum size for cup application
All strands are within cup and fully seated
Minimum solder; however, there is no evidence
of wicking, nor does the solder extend beyond
cup diameter
REJECT
Conductor is too big for cup application
Connection contains loose strands and have been
cut to reduce size of conductor to fit cup
Conductor not in to cup bottom
Solder is wicked and peaked
7-15
TM 750-245-4
Table 7-6. Cup Connectors - Continued
Inspection criteria
Illustration
Excessive solder
Table 7-7. Solder Coverage - Printed Circuit
Inspection criteria
Illustration
ACCEPTABLE
Lead and pad are will wetted
Contour of lead is clearly defined
Solder has a smooth, shiny appearance
MINIMUM ACCEPTABLE
Small imperfections in surface
Smooth, metallic appearance
Maximum solder but lead is discernible
Minimum solder but solder is continuous over
lead and pad
REJECT
Evidence of contamination. Lead is not soldered
Pin hole adjacent to lead
Excess solder, icicle
Pad has dewetted under lead
Lead not alined with conductor
7-16
TM 750-245-4
Table 7-7. Solder Coverage - Printed Circuit - Continued
Inspection criteria
Illustration
Insufficient solder
Table 7-8. Solder Coverage - Connector Pins
Inspection criteria
Illustration
ACCEPTABLE
No surface imperfections
Concave shape, heat, bright solder
Good wetting of pin and pad
Pin contour is well defined
MINIMUM ACCEPTABLE
Minor surface imperfections
Visible line of demarcation between solder and
pin. However, solder flow is not broken. Pin is
completely tinned.
Maximum solder but pin contour is discernible
REJECT
Excess solder
Evidence of dewetting, solder does not cover pad,
base metal showing
Solder incomplete on tip of pin. Base metal
showing. Evidence of contamination indicated
by failure of pins to tin. Note definite break
between pins and solder fillets.
7-17
TM 750-245-4
Table 7-8. Solder Coverage - Connector Pins - Continued
Inspection criteria
Illustration
REJECT- Continued
Insufficient solder
Table 7-9. Solder Coverage - Turret Terminals
Inspection criteria
Illustration
ACCEPTABLE
Minimum wrap
Only sufficient solder used to make connection
Lead and terminal are well wetted and solder has
feathered out to produce a smooth, bright joint
MINIMUM ACCEPTABLE
Hook of lead slightly away from terminal
Joint is well wetted and lead is well defined
Insulation not cut evenly
7-18
TM 750-245-4
Table 7-9. Solder Coverage - Turret Terminals - Continued
Inspection criteria
Illustration
Insufficient solder
REJECT
Hole between lead and turret
Insufficient solder did not wet joint properly
Too much heat
Excess wrap. Extends beyond turret diameter
Table 7-10. Solder Coverage-Bifurcated Terminals
Inspection criteria
Illustration
ACCEPTABLE
Lead well formed; does not extend outside of
terminal
Solder bright; not wicked
Insulation even; good clearance
MINIMUM ACCEPTABLE
Minimum solder
Leads good
Insulation clearance good
7-19
TM 750-245-4
Table 7-10. Solder Coverage - Bifurcated Terminals - Continued
Inspection criteria
Illustration
Maximum solder
REJECT
Insufficient solder
Excess solder
Table 7-11. Soldering of Components
Inspection criteria
Illustration
ACCEPTABLE
Component lead is clean and well tinned
Solder is neat and bright and completely covers
the wire
Component centered between terminals and
seated flush on boards
Leads are not under tension - note offset from
terminal centerline (1/16 inch)
Lead bend has been made at least 1/8 inch from
component body to protect component and lead
weld
7-20
TM 750-245-4
Table 7-11. Soldering of Components - Continued
Inspection criteria
Illustration
MINIMUM ACCEPTABLE
Component leads from a slight loop to offset
component body from terminal centerline
Slight "dimple" adjacent to lead or terminal post
Solder is maximum but lead is well defined
REJECT
Lead and terminal under tension. Insufficient
slack
Component not flush with board
Lead bent at component body
Very poor quality throughout installation
Solder has not wet terminal
Hole adjacent to terminal
Component lead shows evidence of contamination - solder has not wet lead
7-21. Soldering of Hooked Leads
Table 7-12 presents proper solder coverage for hooked leads.
Table 7-12. Soldering of Hook Leads
Inspection criteria
Illustration
ACCEPTABLE
Leads are clean and well tinned
Solder adequate, not wicked
Hooks are well formed
7-21
TM 750-245-4
Table 7-12. Soldering of Hook Leads - Continued
Inspection criteria
Illustration
MINIMUM ACCEPTABLE
Maximum solder
Not wicked
REJECT
Excess solder
Stranded conductor wicked
Dimple in solder may be rosin pit
Cold solder joint
Insufficient solder
Rosin flux entrapment
7-22
TM 750-245-4
CHAPTER 8
WELDING
Section I. INTRODUCTION
as arc, gas, resistance, brazing, thermit, forge,
induction, and flow welding. Of these, the first five are
most commonly known industrially. Some new methods
such as ultrasonic and percussion are still being
researched. Rockets and missiles usually employ, but
are not limited to, arc and gas welding. Most of the
metals and alloys used in Army materiel can be welded
by one or more of the processes described in figure 8-1.
8-1. General
This chapter describes welding and the inspection of
metal and their alloys after the welding operation. A
weld is defined as a fusing of two metals by heating to
suitable temperatures with or without the application of
pressure of filler metal. This filler metal either has a
melting point approximately the same as the base metal
or below it, but above 800 degrees Fahrenheit. There
are many types of welding processes which are known
Figure 8-1. Master chart of welding processes.
8-1
TM 750-245-4
8-2. Joining Mechanism
a. The joining mechanism of welding may be
classified as being either a fusion or a forging action.
The fundamental difference between the two
mechanisms is the temperature at which the joining
weld occurs. The heat generated is a function of the
thermal and electrical characteristics of the materials to
be welded. These characteristics govern which joining
mechanism takes place.
Figure 8-2 illustrates the two basic welds.
b. Fusion occurs when the temperature is great
enough to cause melting of the weld materials at the
point of interface. The molten materials are confined
within the weld materials and, upon cooling, solidity to a
cast structure, termed a "nugget," which binds the
materials together. Lighter metals and materials such
as iron, steel, and nickel exhibit this type of weld.
c. The forge weld is basically a solid state one.
The temperature reached is not high enough to cause
melting but high enough to cause the materials to reach
a plastic state. The pressure exerted by the electrodes
forces the materials into intimate contact, and the
proximity of the atoms of the two materials at the
interface causes a solid state bond. There is no
evidence of a nugget in the forge process., Copper and
other metals possessing low resistivity and high thermal
conductivity are joined by this type of weld, since it is
difficult to localize the heat of the interface.
8-3. Preparation of Metal for Welding
a. The properties of a welded joint depend partly
on the correct preparation of the edges being welded.
All scale, rust, oxides, and other impurities must be
removed from the joint edges or surfaces to prevent
their inclusion in the weld metal. Edges should be
prepared to permit fusion without excessive melting.
Care should be taken to keep to a minimum the heat
loss due to radiation into the base metal from the weld.
Properly prepared joints will give a minimum of
expansion on heating and contraction on cooling.
b. The preparation of the metal for welding is
governed by form, thickness, kind of metal, the load
which the weld will be required to support, and the
available means for preparing the edges to be joined.
Figure 8-2. Basic types of welds.
Section II. TYPES OF WELDS AND PROCESSES
electrodes. Welds are made with or without application
of pressure and with or without filler metals.
a. Metal Electrodes.
(1) Bare metal arc welding. The arc is drawn
between a bare or lightly coated electrode and the
workpiece. Filler metal is obtained from the electrode
and neither shielding nor pressure are used.
(2) Stud welding. The arc is drawn between a
metal stud and the workpiece. The molten surfaces to
8-4. General
This section is included so that you may become
familiar with all types of welds and their processes. he
more knowledge you possess, the better qualified you
will be to inspect.
8-5. Arc Welding
In this process, the weld is produced by the extreme
heat of an electric arc drawn between an electrode and
the workpiece, or in some cases, between two
8-2
TM 750-245-4
be joined are forced together under pressure. No
shielding is used.
(3) Inert-gas shielded stud welding.
This
process is the same as that used for stud welding, (2)
above, except that an inert-gas, such as argon or helium
is used for shielding.
(4) Submerged arc-welding. The arc is drawn
between an electrode and the workpiece, A grandular
flux completely surrounds the end of the electrode and
shields the entire welding action. Pressure is not used
and filler metal is obtained from the electrode.
(5) Inert-gas tungsten-arc welding (TIG). The
arc isdrawn between a nonconsumable tungsten
electrode and the workpiece. Shielding is obtained from
an inert-gas or gas mixture. Pressure and/or filler metal
may or may not be used. Operation of typical inert-gas,
shielded arc-welding machines, are explained in TM
53431-211-15 and TM 3431-213-15.
(6) Inert-gas metal-arc welding (MIG). The
arc is drawn between a filler metal electrode and the
workpiece. Shielding is obtained from an inert-gas, gas
mixture, or a mixture of a gas and a flux.
(7) Shielded metal-arc welding. The arc is
drawn between a covered metal electrode and the
workpiece. Shielding is obtained from decomposition of
the electrode covering. Pressure is not used and filler
metal is obtained from the electrode.
(8) Atomic-hydrogen welding.
The arc is
maintained between two metal electrodes in an
atmosphere of hydrogen. Pressure and/or filler metal
may or may not be used.
(9) Arc-spot welding. A weld is made in one spot by drawing the arc between an electrode and the
workpiece. The weld is made without preparing a hole
in either member. Filler metal, shielding gas, or flux
may or may not be used.
(10) Arc-seam welding. A continuos weld is
made along faying surfaces by drawing the arc between
an electrode and the workpiece. Filler metal, shielding
gas, or flux may or may not be used.
b. Carbon Electrode.
(1) Carbon-arc welding. The arc is drawn
between a carbon electrode and the workpiece. No
shielding is used. Pressure and / or filler metal may or
may not be used.
(2) Twin carbon-arc welding. The arc is
drawn between two carbon electrodes. Shielding and
pressure are not used. Filler metal may or may not be
used.
(3) Inert-gas carbon-arc welding. The arc is
drawn between a carbon electrode and the workpiece.
Shielding is obtained from An inert gas or gas mixture.
Pressure and / or filler metal may or may not be used.
(4) Shielded carbon-arc welding. The arc is
drawn between a carbon electrode and the workpiece.
Shielding is obtained from the combustion of a solid
material fed into the arc or from a blanket of flux on the
work or both. Pressure and / or filler metal may or may
not be used.
8-6. Thermit Welding
This is a welding process in which a weld is made by
heating with superheated liquid metal and slag resulting
from a chemical reaction between a metal oxide and
aluminum. Filler metal, when use, is obtained from the
liquid metal. Pressure may or may not be used.
a. Nonpressure Thermit Welding. In this thermit
welding process, no pressure is used and the filler metal
is obtained from the liquid metal.
b. Pressure Thermit Welding.
In this thermit
process, pressure is used and the liquid metal is not
used as a filler metal.
8-7. Gas Welding
This is a group of welding processes in which a weld is
made by heating with a gas flame or flames. Pressure
and/ or filler metal may or may not be used.
a. Pressure Gas Welding. A process in which a
weld is made, simultaneously over the entire area of
abutting surfaces, by heating with gas flames obtained
from the combustion of a fuel gas with oxygen and by
the application of pressure. No filler metal is used.
b. Oxy-Hydrogen Welding. A process in which the
heat is obtained from the combustion of hydrogen with
oxygen. No pressure is used and filler metal may or
may not be used.
c. Air-Acetylene Welding. A process in which the
heat is obtained from the combustion )t) acetylene with
air. No pressure is used and filled metal may or may
not be used.
d. Oxy-Acetylene Welding. A process in which the
heat is obtained from the combustion of acetylene with
oxygen. Pressure and/or filler metal may or may not be
used.
8-8. Forge Welding
This is a group of welding processes in which a weld is
made by heating in a forge or other furnace and by
applying pressure or blows.
a. Roll Welding. A process in which heat is
obtained from a furnace and rolls are used to apply
pressure.
b. Die Welding.
A process in which heat is
obtained from a furnace and dies are used to apply
pressure.
8-3
TM 750-245-4
8-11. Resistance Welding
This is a welding process in which a weld is made by
heat obtained front resistance of the work to the flow of
an electric current in a circuit of which the work is a part
and by the application of pressure.
a. Resistance-Spot Welding. The size and shape
of the individually formed welds are limited primarily by
the size and contour of the electrodes. The electrodes
apply pressure.
b. Resistance-Seam Welding.
This weld is a
series of overlapping spot welds made progressively
along a joint by rotating the circular electrodes. The
electrodes apply pressure.
c. Projection Welding. These welds are localized
at predetermined points by the design of the parts to be
welded. The localization is usually accomplished by
projections, embossments, or intersections.
The
electrodes apply pressure.
d. Flash Welding.
This weld is made
simultaneously over the entire area of abutting surfaces
by the application of pressure after the heating is
substantially completed. Flashing is accomplished by
expulsion of metal from the joint.
e. Upset Welding.
This weld is made
simultaneously over the entire area of abutting surfaces
or progressively along a joint. Pressure is applied
before heating is started and is maintained Throughout
the heating period.
f. Percussion Welding.
This weld is made
simultaneously over the entire area of abutting surfaces
by the heat obtained from an arc. The arc is produced
by a rapid discharge of electrical energy.
It is
extinguished by pressure percussively applied during
the discharge.
c. Hammer Welding. A process in which heat is
obtained from a forge or furnace and hammer blows are
used to apply pressure.
8-9. Brazing
A group of welding processes in which the filler metal is
a nonferrous metal or alloy with a melting point above
800 degrees Fahrenheit, but lower than that of the
metals to be joined. The filler metal is distributed
between the closely fitted surfaces of the joint by
capillary attraction.
a. Torch Brazing. A process in which a gas flame
produces the necessary heat.
b. Twin-Carbon-Arc Brazing. A process in which
an arc is maintained between two carbon electrodes to
produce the necessary heat.
c. Furnace Brazing. A process in which a furnace
produces the necessary heat.
d. Induction Brazing. A process in which heat is
obtained from resistance of the work to the flow of
induced electric current.
e. Dip Brazing.
A process in which heat is
obtained in a molten chemical or metal bath. The bath
provides the filler metal.
f. Resistance Brazing. A process in which heat is
obtained from resistance to the flow of electric current in
a circuit of which the work is a part.
g. Block Brazing. A process in which heat is
obtained from heated blocks applied to the part to be
joined.
h. Flow Brazing. A process in which heat is
obtained from molten nonferrous filler metal poured
over the joint until the brazing temperature is attained.
8-10. Flow Welding
This is a welding process in which molten-filler metal is
poured over the surfaces to be welded until the welding
temperature has been attained, and the required filler
metal has been added. The filler metal is not distributed
to the joint by capillary attraction.
8-12. Induction Welding
A welding process in which a weld is made by the heat
obtained from resistance of the work to the flow of
induced electric current, with or without the application
of pressure.
Section III. WELD INSPECTION
8-13. General
Welds must be examined to detect any condition or
defect that may impair the reliability of the welded joint.
Examination of the welds may be accomplished by three
methods; nondestructive (visual), destructive, and
metallurgical.
a. Nondestructive. This inspection is visual and
requires that the inspector have a thorough knowledge
of what he is inspecting.
b. Destructive. Destructive inspection of repaired
items is not recommended, because so will destroy the
item. The inspector may have samples made for
destructive inspection. These samples should simulate
the type metal and process of the item it represents.
c. Metallurgical. Metallurgical inspection is not
used by the QC inspector but is included for
informational purposes. At some time, the information
presented may be required.
8-4
TM 750-245-4
suspect an open weld, it is permissible to "probe" the
connection. However, force to the weld must be applied
with caution to avoid stressing the weld.
8-16. Offcenter Weld (Fig. 8-3)
A weld in which either or both of the materials were not
centered between the electrodes.
This type weld
normally causes excessive metal expulsion. In some
cases, if high electrode force has been used, the
offcenter weld can be detected visually by the location
of the indentations of the electrodes.
8-17. Cracked Weld (Fig. 8-4)
Any weld which exhibits a crack in the weldment or
adjacent to it. Cracks normally appear along the fillet or
across the weld area. Cracks are caused by excessive
pressure and / or heat.
Figure 8-3. Offcenter welds.
8-14. Nondestructive Inspection (Visual Inspection)
a. The visual inspection is the only method
available at the present time to nondestructively
evaluate welding repairs. In some cases, a defective
weld can be detected by the unaided eye, but in most
cases an optical aid is required to detect minute defects.
To evaluate the welds visually, illustrations are included
to serve as a guide for the inspector. The inspector
must also exercise his own judgement based on
experience in marginal cases.
b. Every weld in a module must be visually
inspected using an optical aid having a minimum
magnification of 30 power. This necessitates that a
module be inspected in-process at selected points
during fabrication as some welds are inaccessible upon
completion of the package. Upon completion of the
package, all accessible welds should be reexamined to
determine if any damage has resulted from handling
during fabrication.
8-15. Open Weld
A point where a weld has been attempted but no fusion
or forging action has occurred due to misfire of the
welding machine, or a point where a weld is specified by
drawing but has been overlooked by the operator.
When microscopic examination leads the inspector to
Figure 8-4. Cracked welds.
8-5
TM 750-245-4
the result of too much pressure.
The excessive
pressure forces the material to form a bulge while it is in
the plastic stage. A slight amount of bulging is not
considered to be detrimental. Splattering and fragments
of metal extending from the weld zone are actual cases
of metal expulsion and occur because of excessive
pressure and / or heat.
8-18. Deformed Weld (Fig. 8-5)
A deformed weld is one in which the diameter or
thickness of either of the materials has been reduced by
more than 50 percent or the total reduction of both
materials is greater than 35 percent. Deformation is
caused by excessive pressure and / or heat.
8-20. Blow Hole (Fig. 8-7)
A weld in which holes are evident, usually along the
fillet.
These holes are readily detectable under
magnification. Blow holes result from the formation of a
gas pocket in the weld zone which reaches such high
internal pressures that metal is expelled.
Figure 8-5. Deformed welds.
Figure 8-7. Blow hole.
8-21. Pitted Weld (Fig. 8-8)
A weld that exhibits "pits" in either or both of the
materials being joined. In certain cases, when surface
fusion occurs, the molten metal adheres to the electrode
(termed "sticking"). As the electrode force is released,
the material which as adhered to the electrode is pulled
from the parent metal, resulting in a rough and pitted
surface.
Figure 8-6. Splatter weld.
8-19. Metal Expulsion (Figs. 8-5 and 8-6)
A weld which exhibits either excessive bulging of metal
at the interface, "splashed" metal deposits on the
adjoining element, or fragments extending from the weld
interface. Metal bulging (sometimes referred to as
distortion) is not metal expulsion in the true sense of the
word. It appears along the interface of the weld and is
8-22. Excessive Surface Fusion (Fig. 8-9)
A weld in which the weld material has melted to an
excessive degree at the point of interface with the
electrode. A contact resistance exists at this point. If
this resistance is higher than that at the weldment
8-6
TM 750-245-4
interface, or if proper heat balance has not been
attained, the contact area will melt. In certain cases, a
small amount of surface fusion cannot be avoided.
However, it is desirable to keep this to a minimum,
preferably below 10 percent of the lead diameter.
8-23. Excessive Setdown (Fig. 8-10)
Setdown is the degree to which the thinner of the
materials being joined is physically forced into the
thicker material. It is expressed in percent, and is
shown in figure 8-10. Setdown should not exceed 50
percent.
Figure 8-10. Setdown.
8-24. Insufficient Weld
An insufficient weld is one in which fusion or forging
action has occurred, but not to the extent that minimum
weld strength requirements can be met. It is extremely
difficult to detect, and if this condition is suspected to
exist, a number of samples should be obtained from the
machine which produced the questionable welds and
pull tests made. In certain cases, as in round materials
welded to rectangular materials, it may be possible to
detect insufficient welds by observing the fillet at the
interface. The fillet should be evident at least along 75
percent of the interface. Normally, a defective weld will
exhibit two or more of the above conditions. For
example, figure 8-3 is an offset weld in which a weld
splatter is evident. Figure 8-5 exhibits cracks, excess
surface fusion, and excess metal bulging.
Figure 8-8. Pitted weld.
8-25. Destructive Inspection
a. Destructive inspection is made by either a pulltest or metallurgical test. Pull-testing is time consuming
and expensive, and it destroys the product.
Nevertheless, it is the only method available at the
present time for obtaining quantitative data about the
parameters of a weld. Since this method is destructive,
it must be used only on a sampling basis.
b. The pull-test is commonly referred to as a
tensile test of the weld. The test consists basically of
pulling the weld apart by applying a tensile force of
opposite direction to each lead. Besides the tensile
force, there is also a shear force, and, in some
instances, a torsional force applied at the weld joint.
Figure 8-11 illustrates the three methods which are in
use by various companies for pull-testing welds.
Method A of figure 8-11 is the preferred pull-test
method. This method applies an additional stress to the
joint.
Figure 8-9. Excessive surface fusions.
8-7
TM 750-245-4
d. Insufficient pressure is sometimes evidenced by
metal expulsion and sometimes by : he appearance of a
heat affected zone (IIAZ) at the point of contact of the
electrode. Metal expulsion is usually prevalent when
welding heat is high and the foregoing pressure is not
great enough to retain the molten metal. This condition
may also be a result of poor heat inertia. The heat
affected zone results because the low pressure of the
electrodes creates a high -contact resistance at the
electrode and material interface.
e. Excessive pressure is evidenced by metal
expulsion which results in blow holes. In this case, the
pressure is so great that it expels the molten material
from the weld zone.
f. Insufficient heat results in the lack of fusion and,
consequently, a poor weld joint (fig. 8-12).
Figure 8-11. Methods of pull testing.
c. Method A is referred to as the torsion-shear
method of pull-testing. This method places a torsional
force in addition to a tension and shear force on the
weld.
In general, this method results in pull-test
strengths which are much lower than the results
obtained by either of the other methods. Mechanically
locked interconnections are detected by the torsionshear method, whereas they may not be detected by
other methods.
d. The significance of this test is that a quantitative
analysis of the weld strength may be obtained and used
as a basis for determining optimum welding machine
settings. Once the machine has been set, periodic pulltests performed on samples taken from the production
line can be evaluated and the results used as an inprocess check.
8-26. Metallurgical Examination
a. Metallography is the only feasible analytical
technique available for evaluating the quality of a weld.
Metallographic examination reveals the interior of the
weld, enabling the observer to determine what type of
weld has been made, the amount of fusion present, and
any defects present within the weld. However, it takes a
trained and experienced metallographer to interpret the
photomicrographs.
b. Before the interior of the weld can be observed,
the sample must be encapsulated in a rigid substance
and then subjected to a series of grinding and polishing
operations. These operations leave a free surface and a
disturbed crystalline layer above the basic metal for
examination. The free surface and disturbed crystalline
layers are removed by an etching process which, if done
properly, will reveal the true structural characteristics of
the weld.
c. Improper control or selection of welding
variables can be readily determined by metallographic
analysis. Such conditions as excessive or insufficient
pressure or energy, heat unbalance, or combinations of
these have a direct effect on the metallurgical
appearance of the weld.
Figure 8-12. Lack of fusion caused by
insufficient heat.
g. Excessive heat can cause excessively large
nuggets (over penetration) which, in extreme cases,
extend the full width of the material. Over penetration is
undesirable since the recrystallized nugget lacks
ductility. Excessive heat also contributes to metal
expulsion, gas pockets, and shrinkage cavities. Figure
8-13 is a photomicrograph of a weld containing
shrinkage cavities.
h. The nugget of a fusion type weld should exhibit
equal penetration and be free of porosity, inclusions,
blow holes, and shrinkage cavities. Penetration is
defined as the depth to which the fusion extends into the
material and should be at least 20 percent of the
material thickness is. Figure 8-14 illustrates proper
penetration.
i. Improper heat balance can, in many cases, be
detected by the presence of a nugget existing within one
of the materials. Figure 8-15 (top) shows a nugget
8-8
TM 750-245-4
that is contained within the clad of an interconnecting
material. Improper heat balance can be solved by
methods discussed previously.
Figure 8-13. Excessive heat and pressure resulting
in shrinkage cavities.
Figure 8-14. Proper penetration.
j. A sound weld is accomplished when the clad
has been broken through and proper heat balance has
been attained.
k. It has been found, in certain cases involving
welding of solder coated leads, that resistance solder
joint was produced by the weld process, rather than a
true weld. A similar situation exists when welding dumet
to an interconnecting material. Here, the copper sheath
melts and forms a brazed joint. Both of these conditions
have been detected by metallographic analysis.
Figure 8-15. Improper heat balance.
I. The value of metallographic analysis is obvious
and should be performed on welds produced at machine
settings to verify the adequacy of the weld parameters
to produce reliable welds.
However, metallographic analysis and interpretation
should be performed by a qualified metallographeror
metallurgist.
8-9
TM 750-245-4
CHAPTER 9
ADHESIVE BONDING, POTTING, EMBEDDING, AND SEALING
Section I. INTRODUCTION
adhesives; usually the only difference is in the amount
of material used. Adhesive processes require very
small amounts of material as compared to potting
processes. Potting compounds are those resins which
can be converted from liquid to solid state at room or
slightly elevated temperatures and at atmospheric
pressure. Potting compounds are used to protect, hold
in place, and insulate mechanical and electrical parts.
Potting, embedding, and sealing compounds may be
broken into three general categories:
(1) Polyurethanes, epoxies, silicones, and
polysulfides
(2) Sealants
containing
solvents
and
elastomers
(3) Staking sealants (Loctite)
c. Unless otherwise stated, assume that all
information applies to sealants as well as to potting and
embedding compounds. Applied potting compounds are
relatively difficult to repair; be careful when using these
materials on expensive parts.
9-1. General
WARNING
Many of the chemicals used in
adhesive technology are toxic and
present safety hazards to personnel.
Ovens are often used to heat
material. They should always be well
ventilated to prevent inhaling of
chemical fumes. The surrounding
working area should be free of
contamination of materials as they
are skin irritants. Have fire fighting
equipment nearby in case of
emergencies as some chemicals are
highly flammable. Protect the eyes
from exposure. Always have first aid
equipment nearby.
a. This chapter describes adhesive bonding,
potting, embedding, and sealing operations employed in
the maintenance of materiel.
b. In many cases, potting, embedding, and sealing
compounds are identical to compounds used as
9-2. Definitions, Abbreviations, and Terms
The inspector should refer to appendix B for the
definitions, abbreviations, and terms applicable to
adhesive bonding, potting, embedding, and sealing.
Section II. ADHESIVE BONDING
9-3. General
The use of adhesive bonding agents involves five
phases: selection of the proper adhesive, cleaning,
application, curing, and inspection of the finished joint.
It is assumed that the bonding will normally consist of
repair of an existing joint and does not involve the
design of a new joint.
9-5. Cleaning Parts
a. To achieve maximum adhesion, the adherent
surface must be carefully prepared. Clean all potting
areas until they are free from oil, grease, release
agents, rust, moisture, or fingerprints. Skin grease or
perspiration deposited on the adhesion surface may
reduce adhesion by as much as 75 percent. Basically,
four methods are utilized, which are brushing, flowing,
spraying, and rolling.
b. Thoroughly
clean
the
surface
either
mechanically or chemically, depending upon the type of
material and the contaminant to be removed. To
eliminate dirt, scale, rust, and similar contaminants, use
wire brushing, buffing with powdered wire brushes,
sandpapering, sandblasting, or other types of abrasion.
Degrease by solvent cleaning before and after abrading
9-4. Types of Adhesives
The broad use of adhesive bonding has resulted in
development of many different types of adhesives.
Therefore, no discussion will be made here of the
various types. The system technical manuals should be
followed in selecting the proper adhesive, determining
the mixture, and selecting the cure time and
temperature.
9-1
TM 750-245-4
assembly to which the compound is applied to prevent
damage to heat-sensitive compounds or materials.
b. Heat. To apply heat, use a forced-air-circulating
oven, if possible, capable of maintaining temperatures
from 100 to 500 degrees F. within ±10 degrees F.
When heat lamps are used, be careful not to develop
hot spots by concentrating heat in small areas. Rotate
the work on a turntable or by hand to prevent these hot
spots during heatlamp cure.
c. Pressure. Pressure is seldom required during
the cure of most adhesives. If necessary, apply just
enough pressure to insure complete contact.
Elastomeric adhesives do not exude from the glue line.
Do not attempt to force the parts together so hard as to
cause exuding. Resinous or two-part adhesives require
enough pressure on the bonded parts to exude a slight
amount of adhesive at the glue line. Clean off excess
adhesive from the glue line.
d. Single-Part Adhesives.
Thoroughly blend
single-part adhesives, such as solvent dispersions,
before application. Shake the unopened container, or
open the container and stir the con tents, or both.
the surfaces. Remove oils, greases, and most similar
contaminants with chemical cleaning agents such as
solvents and detergents. Make sure no solvent remains
within the mold cavity.
9-6. Applying the Adhesive
Apply adhesives with a spatula, brush, or syringe-type
extruding gun (sealant gun).
Apply only enough
adhesive to insure complete contact between the
adhering areas.
Apply two-part adhesives to one
surface only (the smaller, if possible). Apply one-part
adhesives to both surfaces. The solvent in one-part
elastomeric adhesives must be allowed to dry until tackfree before mating the parts. Since the various types of
solvents require different drying periods, observe strictly
the instructions on drying time. After the parts have
been firmly secured, remove excess adhesive around
the glue line with MEK solvent. Do not use excessive
solvent, the solvent may retard the curing of the
adhesive if allowed to penetrate the glue line.
Thoroughly clean the tools with MEK and wipe them dry
with a clean cloth.
9-7. Using Fixtures in Bonding
a. Aline the parts to be bonded and place them in
contact as instructed in the maintenance document.
Hold and align the bonded part during adhesive cure
with fixtures such as C-clamps, spring clamps, weights,
masking tapes, molded fixtures, or combinations of
these devices in accordance with the specific system
documentation.
Avoid damaging the assembly or
extruding excess adhesive at the glue line when
applying pressure with a fixture.
b. Release agents may be used on fixtures, but
avoid excessive use. Excessive release agents can
contaminate the operator's hands or may enter the
bonded area. Make sure the release agent will have no
damaging effect on the bonding operation or succeeding
operations.
Apply the release agent according to
instructions on the container.
9-9. Final Inspection
The quality of an adhesive bond can best be determined
by assuring that the correct adhesive was used and then
by monitoring the entire bonding process, from cleaning
to curing. If samples can be taken for testing to
destruction, it is obvious that such a test is the best
measure of the adhesive bond. In most instances,
however, inspection must be accomplished without
damage to the adhesive joint.
The following
nondestructive tests will serve to reject most of the
defective bonds:
a. Visual Examination. Check the joint for warpage
and improper alinement. The edges of the joint should
show some flash (extruded adhesive) to indicate that the
proper amount of adhesive was used. The flash should
be hard and nonporous to indicate proper curing. Soft
and tacky shows undercure; burnt and bubbly shows
overcure. Visual examination is the most effective test.
b. Tapping. On large bonded areas, the joint may
be tapped with a hard object. Voids and blisters sound
hollow compared to well-bonded areas.
c. Proof Loading. Load the joint with the same
type of stress anticipated in service. The magnitude of
the stress should be greater than normal but should not
exceed 125 per cent of anticipated load.
9-8. Curing the Adhesive
a. Cure Conditions. All adhesives require some
curing period. The time required varies with the heat
and pressure applied.
Observe the temperature,
pressure, and cure time specified by the instructions for
each particular adhesive. The time and temperature of
cure must be consistent with thermal limitations of the
9-2
TM 750-245-4
Section III. POTTING, EMBEDDING, AND SEALING
product; therefore, adhesion to the mold is essential. In
embedding, however, a release agent must be applied
to the mold before potting. Often, electrical wires with
nonadherent surfaces are encountered. Do not attempt
to abrade or clean electrical wires or sleeved junctions
near the potted area, since the abrasion may cause
short circuits.
d. Check each unit to be processed to insure that
components are in place and ready for potting or
encapsulating. Correct any discrepancies. Aline molds
and components in the fixtures and center all wires and
components protruding from a mold uniformly in the
cavity.
e. When so instructed in the technical
documentation, prime the molds, components,
substrates, or any combination thereof, with suitable
adhesion-promoting agents, or release agents, as
applicable. Make sure the primer will not damage the
molds, components, substrates, or the potting or
encapsulating compound. Apply the primer according to
the instructions on the container.
9-10. General
In many cases, potting, embedding, and sealing
compounds are identical to adhesive bonding
compounds. More material is used in their application
than in bonding. These compounds are resin which can
be converted from liquids to solids at room or slightly
elevated temperatures. Normally, these resins will not
be used in field repair except for the potting of plugs,
jacks, and material containing potting, embedding, and
sealing may be damaged and will have to be inspected
for defects.
The defects may have originated in
manufacture or they may be the result of handling and
environment in service.
The application of these
materials is defined as follows:
a. Potting. The placing of electrical components or
networks in a metal or plastic container which is then
filled with casting resin. The liquid resin then hardens
by cooling or chemical action and the container
becomes an integral part of the finished product.
b. Embedding. A process similar to potting except
that the components and liquid resin material are cast in
a temporary container which is removed when the resin
hardens.
c. Sealing. The placement of a small fillet of resin
sealant over joints or cracks on containers. The sealant
protects the container from foreign material.
Sometimes sealants are used for staking (bonding) parts
together in conjunction with the protection or sealing
action.
9-12. Preparing the Potting Compound
a. Almost all potting compounds require thorough
mixing before combining two-part or applying one-part
sealants to a substrate. If the resin or accelerator
contains no filler and is transparent, it may not require
extensive mixing.
b. If weighing and mixing of two-part systems are
necessary, follow the instructions on the container.
c. Foaming systems, because of their short
reaction time, must be quickly and thoroughly mixed.
Stir the mixture until it is homogeneous, lighter in color,
and more viscous. Do not overmix or the mixture will
be too stiff to pour.
9-11. Preparing Parts to be Potted
a. To achieve maximum adhesion, the adherent
surface must be carefully prepared. Clean all potting
areas until they are free from oil, grease, release
agents, rust, moisture, or fingerprints. Skin grease or
perspiration deposited on the adherent surface may
reduce adhesion by as much as 75 percent.
b. Thoroughly
clean
the
surface
either
mechanically or chemically, depending upon the type of
material and the contaminant to be removed. To
eliminate dirt, scale, rust, and similar contaminants, use
wire brushing, buffing with powdered wire brushes,
sandpapering, sandblasting, or other types of abrasion.
Degrease by solvent cleaning before and after abrading
the surfaces. Remove oils, greases, and most similar
contaminants with chemical cleaning agents such as
solvents and detergents. Make sure no solvent remains
within the mold cavity.
c. While preparing adherent surfaces, consider
which areas do or do not require adhesion. In potting,
the mold or container becomes a part of the finished
9-13. Applying the Potting Compound
a. Potting compounds can be poured, extruded
through sealant guns, (air-pressure activated), dipped,
or spread with a knife or spatula.
Each potting
compound or sealant has its own particular procedure
for application, depending on the material's viscosity. In
general, apply material as dictated by the instructions on
the container. Apply only enough to insure adequate
coverage.
b. Be careful not to trap air in the potting or
encapsulating material while putting the material in
sealant guns or other injection apparatus. Pour the
material down the inside wall when loading the gun or
cartridge.
9-3
TM 750-245-4
accidentally enter the adherent areas as a result of poor
workmanship.
c. While preparing adherent surfaces, consider
which areas do or do not require adhesion. In potting,
the mold or container becomes a part of the finished
product; therefore, adhesion to the mold is essential. In
embedding, however, a release agent must be applied
to the mold before potting. Often, electrical wires with
nonadherent surfaces are encountered. Do not attempt
to abrade or clean electrical wires or sleeved junctions
near the potted area, since the abrasion may cause
short circuits.
d. Check each unit to be processed to insure that
components are in place and ready for potting or
encapsulating. Correct any discrepancies. Aline molds
and components in the fixtures and center all wires and
components protruding from a mold uniformly in the
cavity.
e. After the potting compound has cooled to room
temperature, proceed carefully to remove fixtures and
molds, if required. Trim flash areas as required. Store
fixtures and molds are required to keep them in good
operating condition.
c. Extrude potting material into an open mold by
placing the nozzle at the bottom of the mold and
retracting the nozzle as the cavity fills; keep the nozzle
tip just below the level of compound in the mold. Be
sure to use access holes in closed molds, if they are
provided.
d. Before the potting compound solidifies, examine
any wires or other movable protrusions for alinement,
and realine them as necessary.
e. Special instructions or precautions which must
be observed while applying potting compounds covered
in (1) and (2) below:
(1) Staking sealants. Staking sealants are
noted for the controllability of their adhesive strengths to
metal substrates. These compounds remain liquid
indefinitely until they are confined between closely fitting
metal surfaces in the absence of air; then they change
to an infusible, insoluble state. These compounds are
used in sealing threaded fasteners, plugs, and threaded
fittings against fluid pressure; in locking such threaded
parts against working loose under shock vibration; and
in retaining existing or replacement ball bearings in worn
housings, thus eliminating the need for a press fit.
These compounds are supplied in color coded strengths
and two viscosities for each color. The metal substrate
which the compound contacts is considered the catalyst.
(2) Urethane foams. Access holes in the
mold should be no less than 1/2 inch in diameter, so that
the mixed foam can be poured quickly into the part to be
potted. Bleeding vent holes should be provided if
possible, and if not, the excess foam may exude from
the access hole when the foam rises. Make sure the
mold is heated according to the foaming instructions.
All foams are exothermic; the heat of reaction causes
the chemicals to form gas pockets and cause foaming.
If the heat from the reaction is used up in warming the
mold, poor foaming action will result and the rise will be
insufficient. A general rule, if mold-heating information
is not provided, it to heat the mold from 100 to 120
degrees F. for one hour just before foaming.
9-15. Curing the Potting Compound
a. Cure Conditions. All potting compounds require
some curing period. The time required varies with the
heat applied. Observe the cure time and temperature
specified by the instructions for each particular material.
The time and temperature of cure must be consistent
with thermal limitations of the assembly to which the
compound is applied to prevent damage to heatsensitive components or materials.
b. Heat. To apply heat, use a forced-air-circulating
oven, if possible, capable of maintaining temperatures
from 100 to 500 degrees F. within 3 10 degrees F.
When heat lamps are used, be careful not to develop
hot spots by concentrating heat in small areas. Rotate
the work on a turntable or by hand to prevent these hot
spots during heatlamp cure. Do not exceed curing
temperatures or the potting material, the potted part, or
both may be ruined.
c. Special Instructions. Special instructions or
precautions which must be observed in the cure of
potting compounds are covered in (1) through (3) below:
(1) Silicones. A minimum of 20 percent
relative humidity is necessary to cure silicone materials.
(Heat does not accelerate their cure.) Because of this
moisture requirement, compounds applied thicker than
one-eighth inch require longer to cure than do thin
coatings. As a general rule, for each one-eighth inch
thickness, allow 24 hours at room temperature for cure.
Post cure silicones for 15 to 60 minutes at 10 degrees
9-14. Using Fixtures in Potting
a. Aline parts to be potted as instructed in the
technical documentation. Hold and aline the potted part
during the cure of the potting compound with fixtures
such as molds, C clamps, spring clamps, weights,
masking tapes, molded fixtures, or combinations of
these devices in accordance with the specific
instructions.
b. Release agents may be used on fixtures at
times, but avoid excessive use. Excessive release
agent can contaminate the operator's hands or can
9-4
TM 750-245-4
Fahrenheit above the intended maximum service
temperature of the cured compound.
(2) Polysulfides. Avoid heat curing these
materials at temperatures higher than 120 degrees
Fahrenheit, because the cured potting compound will
gas or become foamlike in appearance. Do not use
heat lamps.
(3) Epoxies.
Allow mixed epoxies which
have generated exothermic heat to return to or below
cure temperature before starting the cure cycle.
b. Avoid testing potted or sealed assemblies.
Instead, if tests are required to determine that the
assembly is properly potted, provide test samples of the
same material. Choose standard test specimens to
satisfy this requirement whenever practical, taking care
to repeat the curing and potting methods employed
during the original procedure. If the test specimen fails,
try to determine the specific cause of failure. Some of
the predominant causes of failure are listed below:
(1) Poor surface preparation of substrates.
(2) Potting compound not properly mixed.
(3) Incorrect ratio of resin to hardener (the
ratio is sometimes reversed).
(4) Each unit container not premixed.
(5) Potting compound shelf-life exceeded
(this can result from incorrect shelf-life markings).
(6) Potting compound not suited for the job.
(7) Substrates not suitable for potting
because of configuration or type of material.
9-16. Final Inspection, Cured Potting Compound
a. Inspect the potting compound to determine if it
is smooth, continuous, and properly cured. Poorly
potted parts may be recognized by: air voids on the
surface and throughout the potted unit; potting material
burned or bubbly from excessive heat or localized heat;
compound soft or tacky from under-curing, discrepant
shelf-life, or lack of heat; substance cracked because of
thermal shock or exothermic reactions, or streaked
because of inadequate mixing.
9-5
TM 750-245-4
CHAPTER 10
LUBRICATION
Section I. INTRODUCTION
10-1. General
This chapter establishes the inspection criteria for items
requiring lubrication after repair. These inspections
require that the inspector have knowledge and special
training in the lubrication of all types of equipment.
a. Refer to applicable system technical manuals
(TM), technical bulletins (TB), and lubrication orders
(LO) for applicable coverage of lubrication.
b. The inspector should refer to appendix B for the
definitions, abbreviations, and terms applicable to
lubrication.
10-2. Reference
Section II. APPLICATION
10-3. General
a. The best lubricant will fail to accomplish its
purpose if not applied to the moving surfaces and in the
proper amounts.
b. There are many methods of applying lubricants
and new methods are being developed as new
lubricants and new equipment are developed. The
inspector should consult the applicable system LO's for
proper lubrication interval, amount, and application.
c. Most lubricants are applied with hand grease
guns, pressure grease guns, oil cans, special package
applicators, brush or cloth-smearing.
c. Damage electronic components.
d. Short electric or electronic components.
e. Drip onto hot surfaces and cause fires, smoke,
or vapor.
f. Contaminate brake linings, clutches, etc.
g. Interfere with friction drives.
h. Contaminate air or gas in piping.
i. Interfere with dial or other instrument operation.
j. Discolor dials. stickers, or instruction panels.
10-5. Under-Lubrication
a. Under-lubrication can be caused by several
factors, some of which are insufficient lubricant,
inadequate seals, wrong lubricant, high temperatures,
high pressures, and lubricant contamination.
b. Insufficient lubrication can cause noise, wearing,
heat, fire, breakage, and many other types of failures
and hazards.
10-4. Over-Lubrication
Over-lubrication can be as detrimental as under
lubrication in the following ways:
a. Cause seal leakage.
b. Drip on valuable materials.
Section III. INSPECTION PROCEDURES
10-6. General
The inspection procedures are general and should be
supplemented with reference to system documentation.
10-8. Bearings
a. In-Process. Inspection of bearings in most
cases will have to be accomplished during an in-process
inspection. Inspection should cover seals, bearing
conditions, and alinement, lubricant contamination, and
under or over-lubrication.
b. Final.
During final inspection, the bearing
should be operated to insure proper alinement and
lubrication. In most cases, this will require an
10-7. Engines
Inspect for correct engine oil and oil filters. Check oil
seals to insure there is no leakage. Check against
lubrication order to insure that all prescribed points are
adequately lubricated.
10-1
TM 750-245-4
operational check of the items in which the bearing was
replaced.
10-11. Oil Seals
In any lubricating system, it is just as important to "seal
in" the lubricant as it is to "seal out" contamination. The
inspector can insure compliance by in-process
inspection of oil seal installation and close checks for
leakage.
10-9. Gears
a. The inspector must be familiar with the
operation and purpose of gears before he can determine
when gears are defective and should be replaced.
b. Inspection of gears which usually are encased
will have to be accomplished during an in-process
inspection. The inspector should inspect, using table
10-1 as a reference, for type of gear wear and possible
correction.
c. Final inspection should insure that the proper
lubricants were used, the gears operate properly, and
there is no leakage around seals.
10-12. Oil Filters
Good quality oil filters are necessary to remove
contamination from oil in a circulating system. It is the
inspector's responsibility to inspect to insure that proper
oil filter change has been made. As a general rule,
anytime maintenance is performed on any system which
requires a lubricated part to be changed, the filter should
also be changed. Lubrication orders should be closely
followed here.
10-10. Wire Rope
Inspect wire ropes to insure proper lubrication so that it
will function dependably during service. Lubrication is
especially critical because of exposure to weather, water
washings, dust, and other contaminations. Although
wire rope is lubricated when manufactured, serious
damage can result through internal and external
corrosion and friction if proper lubrication is not
continued.
Refer to lubrication order or technical
manual.
10-13. Miscellaneous
Many other items and components such as fans,
motors, pumps, shafts, flexible couplings, and chains
require constant lubrication, and must be inspected to
assure that quality of lubricant, application methods,
seals, and lubrication practices conform to standards
and lubrication order requirements. A good knowledge
of these components, attention to details of applicable
lubrication orders, and special inspection procedures are
required for adequate inspection, and assurance that
components are kept in required condition.
Table 10-1. Types of Gear Wear Observed After Use
Condition
Type of gear
Probable cause
Possible correction
Abrasion
All types
Contaminants either metal or
other particles
Change oil and flush out case
before renewal.
Burning
All types
Lack of lubricant or overload.
Proved enough oil, decrease load if
possible.
Galling
Bevel, hypoid, spiral
High surface temperature or oil
film rupture.
Use means to reduce operating
temperature. Check type oil being
used. Change per LO.
Pitting
All types
Oil viscosity too low, rough
surface,
too
high
local
pressure.
Increase oil viscosity and substitute
oil, better gear surface finish. Initial
pitting may cease after run-in
period.
Scoring
Bevel, helical, and spur
types
Too low a viscosity oil; sliding
under heavy load; rough
surfaces;
improper
tooth
contact, perhaps due to
misalinement; temperature low
when starting.
Increase oil viscosity or use oil with
EP agent, preheat before starting.
10-2
TM 750-245-4
CHAPTER 11
PRESERVATION, PACKAGING, AND PACKING
11-1. General
a. This chapter contains information required for
field inspection to assure that preservation, packaging,
and packing conform to prescribed standards.
b. The protection of equipment from hazards of
climate and transportation involves the application of
packaging and packing materials. Proper cushioning
(fig. 11-1) adequately prevent damage resulting from
exposure to those hazards.
(a) Preservation and packaging. Level
A, military package.
(b) Packing. Level B, limited military
pack, except when items having a probable overseas
demand are individually parked in shipping containers,
level A, military pack, should be used.
(2) Items for routine overseas supply. Items
in this category are those which are to be shipped in
established channels or patterns for consumption at
oversea land-based destinations having favorable
storage conditions.
(a) Preservation and packaging. Level
A, military package, or level B, limited military package,
as required by the nature of the item and shipping and
storage experience.
(b) Packing. Level A, military pack, or
level B, limited military pack, as required by the nature
of the item and shipping and storage experience.
(3) Items for immediate use overseas,
destination known. Items in this category are those
which are to be shipped to an overseas activity for use
upon receipt; for example, parts for repair of essential
inoperative equipment.
(a) Preservation and packaging. Level
B, limited military package, or level C, minimum military
package, as required by the nature of the item and
shipping and storage experience, except that unboxed
items may require level A, military package protection.
(b) Packing. Level A, military pack, or
level B, limited military pack, as required by the nature
of the item and shipping and storage experience.
(4) Items for domestic use, redistribution
expected. Items in this category are those which will be
stored and redistributed in the supply system and
ultimately used at a domestic activity.
(a) Levels for known covered storage.
Preservation and packaging should be level A, military
package, level B, limited military package, or level C,
minimum military package, as required by the nature of
the item and shipping and storage experience. Packing
should be level B, limited military pack, or level C,
minimum military pack, except that when water
transportation is involved, packing should be in
accordance with "items for routine overseas supply,"
above.
11-2. References
The inspector should refer to appendix A for the
references applicable to preservation, packaging, and
packing.
11-3. levels of Protection
a. Level A Military Pack. This is the level of
packing which will afford adequate protection during
shipment, handling, indeterminate storage, and
worldwide redistribution.
b. Level B Limited Military Pack. This is the level
of packing which will afford adequate protection against
damage during multiple shipments and handling and
covered storage.
c. Level C Minimum Military Pack. This is the level
of packing which will afford adequate protection against
damage during direct shipments from supply sources to
the first receiving activity for immediate use. This level,
in general, will conform to applicable carrier rules and
regulations and may be the supplier's commercial pack
when such meets the requirements of this level.
11-4. Application of the Levels of Packing
a. Determining Factors. Application of the levels
of packing is based upon such factors as destination,
use, storage conditions, and type of material to be
shipped.
b. Guidelines. For the judicious establishment of
requirements for levels A, B, and C, the military services
have agreed upon the following guidelines:
(1) Items for indeterminate use. Items in this
category are those for which the ultimate destination,
handling, storage conditions, or storage duration is
unknown and cannot be determined either at the time of
procurement or when reserved, packaged, and packed
at a supply activity, installation, or commercial facility.
11-1
TM 750-245-4
Figure 11-1. Functions of Cushioning
11-2
TM 750-245-4
(b) Interior containers.
The interior
reusable metal container is constructed of a lighter gage
steel than the exterior container and is not fabricated
with rolling hoops. Two styles or types of manufactured
containers are procured. The first is the welded-seam
construction and the second is the deep-drawn seamless
style. These containers are constructed with a fully
removable cover which is secured in place by means of
a removable ring, bolt, and nut, Interior containers are
available in eight different sizes.
(2) Containers, metal, nonreusable. Cans,
pails, and drums. These containers are in the category
generally classified as nonreusable, one-way containers
and are available in a variety of types and classes and
with different methods of closure.
(3) Other rigid containers.
As already
mentioned, glass, plastic, etc., can also be found in rigid
container form.
(4) Fiberboard and paperboard containers.
There are various fiberboard and paperboard containers
which are acceptable.
(b) Levels
for
open
storage.
Preservation and packaging should be level A, military
package. Packing should be level A, military pack.
(5) Items for immediate domestic use. Items
in this category are those which will be used upon
receipt at the first domestic receiving activity.
(a) Preservation and packaging. Level
C, minimum military package.
(b) Packing. Level C, minimum military
pack.
c. Packing for Domestic Shipment. When different
packaged and packed items are consolidated in a
shipping container necessitating unpacking at the first
receiving activity for shelf storage until selected for
shipment to a second destination, level C shipping
containers should be used.
11-5. Containers
a. Rigid Containers. There are at present many
different containers which would fit the definition of rigid
container.
Examples of these are reusable metal
containers, nonreusable or one-way containers,
fiberboard (spirally wound) containers, glass containers,
plastic containers, etc.
(1) Reusable metal containers.
Reusable
metal containers are found in two general
classifications: exterior and interior.
(a) Exterior containers.
Exterior
reusable metal containers are similar to a metal drum in
construction.
These containers incorporate a fully
removable cover with a gasket and a bolted ring
closure. All parts of the container are interchangeable
within each style. Exterior containers are available in
seven different sizes.
11-6. Humidity Indicators (fig. 11-2)
Humidity indicators shall be used unless otherwise
specified. As applicable, the indicator shall be located
behind inspection windows or immediately within the
closing edge, face, or cover of the barrier. The indicator
shall be located as far as practicable from the nearest
unit of desiccant.
Other color change humidity
indicators will be subject to approval of the procuring
agency. Externally mounted indicating elements or
devices, when specified, shall be installed in place, or
Figure 11-2. Humidity Indicators.
11-3
TM 750-245-4
permanently calibrated, reacts quickly to humidity
change, and is used for determining relative humidity
within rigid containers and flexible water-vapor-proof
barriers.
when required.
Externally mounted color change
indicators, unless otherwise specified, shall conform to
specification entitled "Indicator, Humidity, Plug Color
Change. This indicator is a metal, plug type which is
Section III. INSPECTION
11-7. General
At this level, a 100 percent inspection is desirable. The
procedures used may be a compilation of checklists,
routing cards, inspection sheets, test procedures, or
other documents normally used to define operations.
11-8. Inspection Points
The following points are based upon the assumption that
the inspector will have at hand all necessary documents
covering packaging and packing. These points are in
addition to regular inspection procedures, such as
accountability, dimensional checks, etc.
a. Are the containers or packaging materials in
contact with the item chemically nonreactive to the
hazardous material(s)?
b. Is movement within the container prevented or
controlled by shock mount systems?
c. Does the identity of the item check with the
shipping instructions and bill of lading?
d. Are the contents (if more than one item)
compatible with no inert parts separately packaged?
e. Does the container qualify under the applicable
requirements?
f. Is the shipping container closed in conformance
with applicable requirements?
g. Are unit or intermediate container, net and gross
weight, or volume within the limits allowed?
h. In addition to other required markings, is the
proper shipping name shown exactly?
i. Are other required precautionary markings
shown correctly?
j. Are the proper labels affixed, as required by the
applicable tariff?
k. Does an empty container have obliterated
explosive and hazardous markings, proper shipping
names, and any explosive or hazardous label covered
with the "EMPTY" label?
I. Is the classification of the material valid and
correct?
m. Is the container authorized for this material
correct for volume, weight, mode of transportation?
n. Is the container marked with one of the
following: DOT specification, Government specification,
BA number?
o. Do drums have DOT or military specification
inspection schedule maintained?
Figure 11-3. Deficiencies
11-4
TM 750-245-4
Figure 11-4. Method of Preservation, Packaging, and Packing
(7) Frame members failed
(8) Inadequate
blocking,
bracing
cushioning
(9) Cleats broken
(10) Ends knocked out
(11) Sheathing broken
(12) Boards split
(13) Nails pulled
(14) Fiberboard panels torn
(15) Improper type container used
(16) Container not waterproof
(17) Nonspecification materials used
(18) Case liner damaged or unsealed
(19) Excessive packing or waste space
(20) Container came open
c. Marking.
(1) Old marking not obliterated
(2) Marking not legible
(3) Tags or labels not waterproofed
(4) Inadequate packing list protector
(5) Incorrect or incomplete marking
(6) Markings improperly applied
(7) Incorrect service markings
d. Loading, Sowage, or Handling.
(1) Load improperly trimmed
(2) Center of gravity not considered
(3) Sling damage
(4) Improper stowing
p. Was the DOT certification on B / L signed? (The
most frequently appearing item of DD 6's.)
q. Are the nomenclature and special markings
correctly shown on the container and consistent with
shipping papers?
r. Was the carrier really inspected and the DD 626
filled out?
s. Are old placards removed, markings obliterated,
and/or EMPTY labels affixed to empty containers (as
required) before reshipment of return?
11-9. Storage Inspection
a. Preservation or Packaging (Figs. 11-3, 11-4,
11-5 and 11-6).
(1) No preservative
(2) Improper preservative
(3) Preservative improperly applied
(4) Corrosion
(5) Contamination
(6) Package improperly sealed (Fig. 11-7)
(7) Inadequate blocking or cushioning
(8) Nonspecification materials used
(9) Excessive preservation or packaging
b. Packing (Figs. 11-3, 11-4, and 11-5).
(1) Container overloaded
(2) Container crushed
(3) Container wracked
(4) Container punctured
(5) Wire or strap broken or loose
(6) Straps inadequate or inadequately
fastened
11-5
or
TM 750-245-4
(11)
(12)
(13)
(14)
Inadequate bulkhead or gate
Inadequate doorway protection
Rough handling
Regulations violated
Figure 11-6. Method of Packaging and Packing
Missile Items
Figure 11-5.
(5)
(6)
(7)
(8)
(9)
(10)
Method of Preservation and Packaging.
Improperly arranged load
Improper dunnaging
Load not properly nested
Inadequate tiedown or lashing
Steel strapping failure
Improper blocking or bracing
Figure 11-7. Package Failure.
11-6
TM 750-245-4
APPENDIX A
REFERENCES
A-1
GENERAL
All the documents referenced in this appendix are not used in this TM, but are included as an aid to the inspector. He
should obtain and familiarize himself with these documents; by doing so he will increase his knowledge and be more
capable of inspecting properly.
A-2
PUBLICATION INDEXES
DA Pamphlets of the 310series and PAM 108-1 should be consulted frequently for the latest changes or revision of the
references given in this Appendix and for new publications relative to the material covered in this technical manual.
A-3
OTHER PUBLICATIONS
Adhesives: Description, use, bonding techniques; properties........................................................................ TB ORD 1032
Batteries, Dry .................................................................................................................................................. TB 34-9-171
Batteries, Dry, Shelf life inspection...................................................................................................... TB 9-6135-200-20/1
Bearings, Antifriction: Inspection; care; maintenance .......................................................................................... TM 9-214
Chassis, Miscellaneous (electrical equipment)
Capacitance & resistance check....................................................................................................... TB 9-4900-250-50/2
Circuit continuity check .................................................................................................................... TB 9-4900-250-50/1
Resistance ....................................................................................................................................... TB 9-4900-250-50/8
Chassis coating compound: Description; application; etc................................................................................ TB ORD 401
Chemical products: Storage; handling; fire precautions; safety..........................................................................TB CML 50
Chemicals, Hazardous: Storage, shipment and handling ..................................................................................... TM 3-250
Circuit breakers: Hand operated ...................................................................................................................... TB 34-9-182
Compressed air characteristics: Supply pressure & hoses ............................................................................... TB 34-9-244
Corrosion control: Guided missile systems ........................................................................................................... TB 9-337
Electrical communications systems: Definitions and abbreviations ............................................................... TM 11-486-11
Electrical indicating instruments, Repaired:
Inspection requirements .................................................................................................................... TB 11-6625-666-50
Electrical wiring................................................................................................................................................... TM 5-760
Electricity: Fundamentals .................................................................................................................................. TM 11-661
Electronic communication equipment: Military Handbook................................................................................ TM 11-487A
Frequency Techniques: Electronic..................................................................................................................... TM 11-667
Fungus-resistant treatment: Signal equipment...............................................................................................TB SIG 355-3
Gaskets: Description; application ......................................................................................................................... TB 9-225
Gaskets: Types; uses, etc. ..............................................................................................................................TB FNG 346
Glossaries: Welding terms and definitions...........................................................................................................TB 34-9-7
Guided missile systems: Corrosion control and treatment..................................................................................... TB 9-337
Guided missiles & rockets: Painting & marking................................................................................................ TB 746-92-1
Hose assemblies: Hydraulic (general) .............................................................................................. TB 9-1440-250-50/ 10
Hose assembly handbooks: Cross reference data ....................................................................................... TB 700-4720-1
Identification plates: Communication equipment ................................................................................................SB 11-263
Launcher material, Rocket: Color and marking................................................................................................ TB 746-95-2
Lubrication: Ordnance material ........................................................................................................................... TM 9-273
Magnesium products: Welding, joining and finishing ...................................................................................... TB ORD 638
Materials testing: Equipment, methods................................................................................................................ TM 5-530
Materiel, Pre-positioned: Inspection, care & preservation .................................................................................. TM 38-450
Name plates: Communication equipment ...........................................................................................................SB 11-263
A-1
TM 750-245-4
Oil seals: Description; application......................................................................................................................... TB 9-255
Optics: Handbook for the laboratory specialist..................................................................................................... TM 9-237
Ordnance materiel:
Calibration of test equipment ........................................................................................................ TB ORD-1026 / series
Cleaning: methods, materials, etc ................................................................................................................. TM 9-208-1
Cleaning, preserving, abrading, etc., materials................................................................................................. TM 9-247
Inspection: radiographic method ............................................................................................................... TB ORD 1034
Lubrication ....................................................................................................................................................... TM 9-273
Packaging: Army general supplies........................................................................................................................SB 9-156
Packing: Supplies and equipment ......................................................................................................................SB 38-100
Packing (for sealing joints):
Description; application ..................................................................................................................................... TB 9-255
Types; uses; etc.......................................................................................................................................... TB ENG 346
Painting: Field use, instructions........................................................................................................................... TM 9-213
Painting and marking: Guided missiles and rockets......................................................................................... TB 746-92-1
Pneumatic equipment: Maintenance & repair ................................................................................................... TB ENG 28
Preservative materials: Rubber preservative coaring ........................................................................................... TB 9-248
Radar: Pulse system performance: Theory; measurement T ............................................................................. TM 11-759
Radio equipment: Trouble shooting and repair .................................................................................................TM 11-4000
Rocket launcher materiel: Color and marking .................................................................................................. TB 746-95-2
Servo systems: Electronic ................................................................................................................................. TM 11-674
Solder & soldering: Materials; methods, equipment .......................................................................................... TB SIG 222
Supplies & equipment, Military: Preservation, packaging,
packing ....................................................................................................................................................... TM 38-230-1
Terms and definitions...................................................................................................................................... TB 34-9-256
Threads: Line pipe, valves, fittings and flanges .................................................................................................TB 34-9-71
Tires, Pneumatic: Care; maintenance ............................................................................................................ TM 9-1870-1
Tires, Solid-rubber: Identification; inspection;
classification; maintenance; disposition...............................................................................................TM 9-2630-200-14
Tires & tubes, Pneumatic: Repair and rebuild.................................................................................................... TM 9-1871
Training: Radio repair personnel ....................................................................................................................... TM 11-477
Transistors: Basic theory; applications............................................................................................................... TM 11-690
Transmission lines: Radio frequency ................................................................................................................. TM 11-675
Transmission lines: Theory; practice ................................................................................................................. TM 11-679
Tubes, Electron: Basic theory & application....................................................................................................... TM 11-662
Welding: Design, procedures & inspection ....................................................................................................... TM 5-805-7
Welding Machine, Arc: General and inert gas shielded
Transformer-Rectifier type, ac and dc; 300 Ampere rating
at 60 percent duty cycle ......................................................................................................................TM 5-3431-213-15
Welding set, arc inert gas shielded consumable metal electrode
for 3/64 in. wire, dc, 115 v..................................................................................................................TM 5-3431-311-15
Welding terms and definitions: Glossary ...........................................................................................................TB 34-9-67
Wire rope: Standardization.............................................................................................................................. TB 34-9-125
A-2
TM 750-245-4
APPENDIX B
GLOSSARY
C.................................. centigrade, cycle(s), hundred
CA ............................... can, cartridge
CAND .......................... candelabra
CAND-BAY-BASE........ candelabra bayonet base
CARB........................... carbon
CARB-S ....................... carbon steel
CD ............................... cadmium
CD- OR ZNPLTD ........................... cadmium- or zinc-plated
CD-PLTD ..................... cadmium-plated
CFM............................. cubic feet per minute
CHAM .......................... chamfered)
CHG............................. change
CI................................. cast iron
CK ............................... countersunk
CK-HD ......................... countersunk head
C / L............................. center line
CL................................ coil
CN ............................... can
CNTR OR CR .............. container
C / O ............................ consists of
CO ............................... container
COAX .......................... coaxial
COLD-FIN-S ................ cold-finished steel
CONE-PT..................... cone point
COND .......................... conductor(s)
COP............................. copper
COP-PLTD................... copper plated
CORR-RES-S .............. corrosion-resistant steel
COT............................. cotton
CP ............................... concrete piercing, candle power
CPS ............................. cycles per second
CROSS-RECESSRD-HD ......................... cross recess round head
CROSS-RECESSTR-HD ......................... cross recess truss head
CR-PLTD ..................... chromium plated
CT................................ carton
CTD ............................. coated
C TO C ........................ center to center
CUP-PT ....................... cup point
CUR............................. current
CY ............................... cylinder(s)
DBLE ........................... double
DBLE-CONTACT ......... double contact
DC ............................... direct current
DEG............................. degree(s)
DIA .............................. diameter
DIM.............................. dimension(s) (al)
B-1. GENERAL
This appendix is used by the inspector to find
abbreviations, symbols, definitions of terms, color code
tables, temperature charts, and other general
information which will assist during inspection.
B-2. ABBREVIATIONS
The abbreviations listed below are those authorized.
These abbreviations may appear in the system
documentations, inspection forms, or other applicable
documents.
AA................................ two hundred fifty
ABEC........................... Annular Bearing Engineering
Committee
AC ............................... alternating current
ADPT ........................... adapter
AL ................................ aluminum
AL-ALLOY.................... aluminum alloy
AL-BZ .......................... aluminum bronze
ALLOY-S...................... alloy steel
AMP............................. ampere(s)
ANLD ........................... annealed
ANODIC-FIN................ anodic finish
ANPT ........................... Aeronautical National Taper
Pipe Thread
AR ............................... as required
ASB ............................. asbestos
AV................................ twenty five
AWG............................ American Wire Gage
AX................................ twenty
BA................................ bale
BAY ............................. bayonet (lamp base)
B-HD............................ button head
BDG-HD....................... binding head
BG ............................... bag
BK................................ book
BL ................................ barrel
BLK.............................. Color Coding (electric cable
identification) black
BLU.............................. Color Coding (electric cable
identification) blue
BLUNT-PT ................... blunt point
BR ............................... brass
BRGT........................... bright
BRN ............................. Color Coding (electric cable
identification) brown
BT................................ bottle
BX................................ box (es)
BZ................................ bronze
B-1
TM 750-245-4
I ................................... iron
ID................................. inside diameter(s) (dimension)
INCAND ....................... incandescent
IND .............................. inductance, induction
INS .............................. insulated, insulating, insulator
INST ............................ instantaneous
INT............................... internal
INT-TEETH .................. internal teeth (lock washer)
JT ................................ joint
KC ............................... kilocycle(s)
KG ............................... keg
KNURLED-HD.............. knurled head
KT................................ kit
KV................................ kilovolt(s)
KW .............................. kilowatt(s)
LACQD ........................ lacquered
LEA.............................. leather
LG................................ long (length)
LH................................ left hand
LIN............................... linear
LKG ............................. locking
LL ................................ fifty
LUBR ........................... lubricator, lubricating,
lubrication
MA ............................... milliampere(s)
MACHST...................... machinist
MC............................... megacycle(s)
MED............................. medium
MEG ............................ megohm(s)
MF ............................... thousand ft
MH............................... millihenry(ies)
MI ................................ malleable iron
MIN.............................. miniature
MIN-BAY-BASE ........... miniature bayonet base
MM .............................. millimeter(s)
MTG ............................ mounting(s)
MTL ............................. metal
MX ............................... thousand
NC ............................... American
National
Coarse
Thread
NEF ............................. American National Extra Fine
Thread
NF................................ American National Fine Thread
NI................................. nickel
NI-PLTD....................... nickel plated
NI-SIL .......................... nickel silver
NOM ............................ nominal
NPT ............................. American Standard Taper Pipe
Threads
NPTF ........................... American Standard Taper Pipe
Threads (Dryseal)
NS ............................... American
National
Special
Thread
OD ............................... outside diameter (dimension),
olive drab
OPNG .......................... opening
DLD ............................. drilled
DLD-F / C-PIN.............. drilled for cotter pin
DLD-F / LKG-WIRE...... drilled for locking wire
DOG-PT....................... dog point
DP ............................... double-pole
DPDT........................... double-pole, double-throw
DPST ........................... double-pole, single-throw
DR ............................... double-row, drum
DT................................ double-throw
DZ................................ dozen
EA................................ each
ENMLD ........................ enameled
EN ............................... envelope
ENV ............................. envelope
ETC ............................. et cetera (and so forth)
EXTER......................... external
EXT-TEETH................. external teeth (lock washer)
F .................................. Fahrenheit
FASTNR ...................... fastener
FBR ............................. fiber
FC................................ fire control
FED SPEC................... Federal Specification
FIGS ............................ figures
FIL ............................... filament(s)
FIL-HD ......................... fillister head
FIN............................... finish(ing)
FL ................................ flat
FL-CK-HD .................... flat countersunk head
FL-FIL-HD.................... flat fillister head
FL-HD .......................... flat head
FL-PT........................... flat point
FLGD ........................... flanged
G.................................. Color Coding (electric cable
identification) gold
GA ............................... gage, gallon(s)
GL................................ gallon(s)
GLVD........................... galvanized
GM............................... gram (s)
GR ............................... grain(s), gross
GRN............................. Color Coding (electric cable
identification) green
GY ............................... Color Coding (electric cable
identification) gray
H.................................. height, high
HALF-RD ..................... half round
HD ............................... head, hundred
HDL ............................. handle(d)
HDLS ........................... headless
HEX ............................. hexagon(al)
HEX-HD ....................... hexagon head
HEX-SOCKET.............. hexagon socket
HEX-SOCKETHD ............................... hexagon socket head
HF................................ hundred feet
HP ............................... horsepower
HY ............................... henry(ies)
B-2
TM 750-245-4
SQ-END....................... square end
SQ-HD ......................... square head
SR ............................... single-row
ST................................ single-throw, set
STABIL ........................ stabilotron
STGHT ........................ straight
STLS-S ........................ stainless steel
SV................................ sleeve
SW .............................. switch
SY OR SQ YD ............. square yard
SYN ............................. synthetic
SYN-RU ....................... synthetic rubber
TEMP........................... temperature
TERM .......................... terminal(s)
THD ............................. thread(ed) (s)
THK ............................. thick(ness)
TND ............................. tinned
TND-COP .................... tinned copper
TN-PLTD...................... tin plated
TOL ............................. tolerance
TR................................ tracer(s), transmit-receive
TU................................ tube
TUBR........................... tubular
TUN-FIL....................... tungsten filament
UA ............................... microampere(s)
UF................................ microfarad(s)
UH ............................... microhenry(ies)
UNC............................. Unified Coarse Thread
UNEF........................... Unified Extra Fine Thread
UNF ............................. Unified Fine Thread
UNIV-JT....................... universal joint
U / 0............................. used on
USEC........................... microsecond(s)
UUF ............................. micromicrofarad(s)
U/W ............................. used with
V .................................. volt(s)
VAR ............................. variable
VIO .............................. Color Coding (electric cable
identification) violet
VUL.............................. vulcanize(d)
VX................................ five
W................................. watt(s), wide, width
W /............................... with
W / E ........................... with equipment
WH .............................. watt-hour(s)
WHT ............................ Color Coding (electric cable
identification) white
W / O ........................... without
W TR PRF ................... waterproofed
X .................................. by (as in 2 x 4)
XX................................ ten
YD ............................... yard(s)
YEL.............................. Color Coding (electric cable
identification) yellow
ZN................................ zinc
ZN-CTD ....................... zinc-coated
ZN-PLTD...................... zinc-plated
ORN............................. Color Coding (electric cable
identification) orange
OVAL-HD..................... oval head
OZ ............................... ounce(s)
PAN-HD ....................... pan head
PAPR........................... paper
PASS-FIN .................... passivated-finish
P-BZ ............................ phosphor bronze
PC ............................... piece(s)
PG ............................... package
PHOS-C'D.................... phosphate coated
PKG............................. package
PL ................................ plate, pail
PLTD ........................... plated
POS............................. positive
PR ............................... Color Coding (electric cable
identification) purple, pair
PRI .............................. primary
PT................................ pint
PTF.............................. pipe thread fine
PY................................ pyramid
QT ............................... quart(s)
RAD ............................. radial, radius
RD-END....................... round end
RD-HD ......................... round head
RE ............................... reel
RECEP ........................ receptacle
RECT........................... rectangular
RH ............................... right hand
RL OR RO ................... roll
RMS............................. root mean square
RPM............................. revolutions per minute
RU ............................... rubber
S .................................. steel
SE................................ set
SEC ............................. second(s) (time interval)
SECS........................... sections
SF OR SQ FT .............. square foot
SGLE ........................... single
SGLE-COND................ single conductor
SGLE-CONTACT......... single contact
SGLE-PH ..................... single phase
SGLE-TUN-FIL ............ single tungsten filament
SH ............................... sheet
SHK ............................. shank
SIL-PLTD ..................... silver plated
SL ................................ spool
SLTD ........................... slotted
SM ............................... smooth
SOCKET-HD................ socket head
SP................................ single-pole, spool
SPDT ........................... single-pole, double-throw
SPG............................. spring
SPG-S ......................... spring steel
SPST ........................... single-pole, single-throw
SQ ............................... square
SQ-DRIVE ................... square drive
B-3
TM 750-245-4
B-3. DEFINITIONS AND TERMS
A
ARC WELDING: A group of welding processes in which
a fusion is produced by heating with an electric arc of
arcs, with or without the use of filler metal.
ABRASIVES: Emery cloth or aluminum oxide cloth grit
size 300 to 400 shall be used for cleaning cold, surface
treated soldering iron tips and resistance heating
electrode tips. The use of abrasives for cleaning plated
soldering iron tips should be limited to only experienced
maintenance personnel. This type of cleaning is rarely
required where soldering iron holders are utilized.
AS WELDED: The condition of weld metal, welded
joints, and weldments after welding and prior to any
subsequent thermal or mechanical treatment.
ATOMIC HYDROGEN WELDING: An arc welding
process in which a fusion is produced by heating with an
electric arc maintained between two metal electrodes in
an atmosphere of hydrogen. Pressure and / or filler
metal may or may not be used.
ABRASIVE WEAR: Wear due to hard particles such as
sand, metal, etc., between the surfaces.
ACETONE: A flammable, volatile liquid used in
acetylene cylinders to dissolve and stabilize acetylene
under high pressure.
AXIS OF A WELD: A line through the length of a weld,
perpendicular to a cross section at its center of gravity.
B
ACETYLENE: A highly combustible gas composed of
carbon and hydrogen. Used as a fuel gas in the oxyacetylene welding process.
BACK PASS: A pass made to deposit a back weld.
ACTUAL THROAT: See throat of fillet weld.
BACK STEP: A sequence in which weld bead
increments are deposited in a direction opposite to the
direction of progress.
ADHESIVE WEAR (GALLING WEAR): High surface
temperature or oil film rupture wear.
BACK WELD: A weld deposited at the back of a single
groove weld.
AIR ACETYLENE: A low temperature flame produced
by burning acetylene with air instead of oxygen.
BACK FIRE: The momentary burning back of a flame
into the tip, followed by a snap or pop, then immediate
reappearance or burning out of the flame.
ALLOY: A mixture with metallic properties composed of
two or more elements of which at least one is a metal.
BACKHAND WELDING: A welding technique in which
the flame is directed towards the completed weld.
ALLOY: A mixture with metallic properties composed of
two or more elements of which at least one is a metal.
BACKING STRIP: A piece of material used to retain
molten metal at the root of the weld and / or increase
the thermal capacity of the joint so as to , prevent
excessive warping of the base metal.
ANILINE POINT: The critical solution temperature of a
50-50 mixture of the oil in question with aniline.
ANTI-WICKING TOOL: Special shaped holding type
tweezers, designed to stop capillary flow of liquid solder
to prevent wicking of stranded conductors. These are
manufactured to fit the different wire sizes. These may
be used as thermal shunts during the soldering
operation.
BACKING WELD: Backing in the form of a weld.
BACK UP: In flash and upset welding, a locator used to
transmit all or a portion of the upsetting force to the work
pieces.
ARC BLOW: The swerving of an electric arc from its
normal path because of magnetic forces.
BARE ELECTRODE: An arc welding electrode that has
no coating other than that incidental to the drawing of
the wire.
ARC BRAZING: An electric brazing process wherein the
heat is obtained from an electric arc formed between the
base metal and an electrode, or between two electrodes.
BARE METAL-ARC WELDING: An arc welding process
in which fusion is produced by placing an unshielded arc
between a bare or lightly coated electrode and the work.
Pressure is not used and filler metal is obtained from the
electrode.
ARC CUTTING: A group of cutting processes in which
the severing of metals is accomplished by melting with
the heat of an arc between an electrode and the base
metal. See carbon-arc cutting, metal-arc cutting and
oxy-arc cutting, and air-arc cutting.
BASE METAL: The metal to be welded or cut. In alloys
it is the metal present in the largest proportion.
B-4
TM 750-245-4
BEAD WELD: A type of weld composed of one or more
string or weave beads deposited on an unbroken
surface.
BUTT WELD: A weld in a butt joint.
BEADING: See string bead and weave bead.
CAPILLARY ATTRACTION: The phenomenon by which
adhesion between the molten filler metal and the base
metals, together with surface tension of the molten filler
metal, causes distribution of the filler metal between the
properly fitted surfaces of the joint to be brazed.
C
BEVEL ANGLE: The angle formed between the
prepared edge of a member and a plane perpendicular
to the surface of the member.
BLACKSMITH WELDING: See forge welding.
CARBON ARC CUTTING: A process of severing metals
with the heat of a carbon arc.
BLOCK BRAZING: A brazing process in which fusion is
produced by the heat obtained from heated blocks
applied to the parts to be joined and by a nonferrous
filler metal having a melting point above 800 deg F, but
below that of the base metal. The filler metal is
distributed in the joint by capillary attraction.
CARBON ARC WELDING: A welding process in which
fusion is produced by placing an arc between a carbon
electrode and the work. Pressure and / or filler metal
and / or shielding may or may not be used.
CARBON RESIDUE: The carbon deposit left after
subjecting an oil to high temperatures.
BLOCK SEQUENCE: A building up sequence of
continuous multipass welds in which separated lengths
of the weld are completely or partially built up before
intervening lengths and deposited.
See buildup
sequence.
CARBURIZING FLAME: An oxy-acetylene 'flame in
which there is an excess of acetylene. Also called
excess acetylene or reducing flame.
BLOW HOLE: See gas pocket.
CASCADE SEQUENCE: Subsequent beads are stopped
short of a previous bead giving a cascade effect.
BOND: The junction of the welding metal and the base
metal.
CHAIN INTERMITTENT FILLET WELDS: Two lines of
intermittent filler welds in a T or lap joint in which the
welds in one line are approximately opposite those in
the other line.
BOXING: The operation of continuing a fillet weld
around a corner of a member as an extension of the
principal weld.
CHAMFERING: The preparation of a contour, other than
for a square groove weld for welding on the edge of a
member.
BRAZE WELDING: A method of welding in which a
groove, fillet, plug or slot weld is made by using a
nonferrous fillet metal having a melting point below that
of the base metals but above 800 deg F. The filler
metal is not distributed in the joint by capillary attraction.
CLEANING MATERIAL: Clean, white, lint-free cloth or
tissue used with approved solvents to clean soldered
joints.
BRAZING: A group of welding processes in which fusion
is produced by heating to a suitable temperature above
800 deg F, and by using a nonferrous filler metal having
a melting point below that of the base metals. Filler
metal is distributed between the closely fitted surfaces
of the joint by capillary attraction.
CLEANING
SOLVENTS:
Tetrachloroethylene,
Perchloroethylene, Trichloroethane and Isopropy
Alcohol are the approved cleaning solvents for cleaning
solder connections.
BRIDGING: A welding defect caused by poor
penetration. A void at the root of the weld is spanned by
weld metal.
COATED ELECTRODE: An electrode having a flux
applied externally by dipping, spraying, painting or other
similar methods. Upon burning the coat produces a gas
around the arc.
BUCKLING: Distortion caused by the heat of a welding
process.
COLD SOLDER JOINT: A cold solder joint is the result
of insufficient heat to enable the solder to flow. Quite
recognizable, this joint has a piled up, rough surface,
chalky, without metallic luster.
BUILDUP SEQUENCE: The order in which the weld
beads of a multipass weld are deposited with respect to
the cross section of a joint. See block sequence.
COMMUTATORY CONTROLLED WELDING: The
making of a number of spot or projection welds in which
several electrodes, in simultaneous contact with the
work, progressively function under the control of an
electrical commutating device.
BUTT JOINT: A joint between two base metals in such a
manner that the weld joining the parts is between the
surface planes of both the parts joined.
B-5
TM 750-245-4
COMPOSITE ELECTRODE: A filler metal electrode
used in arc welding, consisting of more than one metal
component combined mechanically. It may or may not
include materials that improve the properties of the
weld, or stabilize the arc.
DEPOSITION EFFICIENCY: The ratio of the weight of
deposited metal to the net weight of electrodes
consumed exclusive of stubs.
DEPTH OF FUSION: The distance from the original
surface of the base metal to that point at which the
fusion ceases in a welding operation.
COMPOSITE JOINT: A joint in which a thermal and
mechanical process is used to unite the base metal
parts.
DEWETTING. Separation of printed or plated circuits
from the circuit board. This is usually the result of
excessive heat being applied during soldering
operations.
Also, failure of solder to flow when
reworking a solder joint due to contamination.
CONCAVITY: The maximum distance from the face of a
concave fillet weld perpendicular to a line joining the
toes.
CONCURRENT HEATING: Supplemental heat applied
to a structure during the course of welding.
DIE: a. Resistance Welding. A member, usually
shaped to the work contour, used to clamp the parts
being welded and conduct the welding current.
b. Forge Welding. A device used in forge welding
primarily to form the work while hot and apply the
necessary pressure.
CONE: The conical part of a gas flame next to the
orifice of the tip.
CONVEXITY: The maximum distance from the face of a
convex fillet weld perpendicular to a line joining the
toes.
DIE WELDING: A forge welding process in which fusion
is produced by heating in a furnace and by applying
pressure by means of dies.
CORNER JOINT: A joint between two members located
approximately at right angles to each other in the form
of an L.
DIP BRAZING: A brazing process in which fusion is
produced by heating in a molten chemical or metal bath
and by using a nonferrous filler metal having a melting
point above 800 F, but below that of the base metals.
The filler metal is distributed in the joint by capillary
attraction.
When a metal bath is used the bath provides the filler
metal.
CORROSIVE WEAR: Wear due to atmospheric or
chemical corrosion.
COVER GLASS: A clear glass used in goggles, hand
shields, and helmets to protect the filter glass from
splattering material.
COVERED ELECTRODE : A metal electrode with a
covering material which stabilizes the arc and improves
the properties of the welding metal. The material may
be an external wrapping of paper, asbestos and other
materials or flux covering.
DRAG: The horizontal distance between the entrance
and the point of exit of a cutting oxygen stream.
CRATER: A depression at the termination of an arc
weld.
E
DROPPING POINT: The temperature at which a grease
will pass from a semisolid to a fluid state.
EDGE JOINT: A joint between the edges of two or more
parallel or nearly parallel members.
CURRENT DENSITY: Amperes per square inch of the
electrode sectional area.
EDGE PREPARATION: The contour prepared on the
edge of a member for welding.
CUTTING TIP: A gas torch tip especially adapted for
cutting.
EFFECTIVE LENGTH OF WELD: The length of a weld
throughout which the correctly proportioned cross
section exists.
CUTTING TORCH: A device used in gas cutting for
controlling the gases used for preheating and the
oxygen used for cutting the metal.
ELECTRODE: a. Metal Arc - Filler metal in the form of
a wire or rod, whether bare or covered, through which
current is conducted between the electrode holder and
the arc.
b. Carbon Arc - A carbon or graphite rod through
which current is conducted between the electrode holder
and the arc.
c. Atomic Hydrogen - One of the two tungsten rods
between the points of which the arc is maintained.
CYLINDER: A portable cylindrical container used for
transportation and storage of a compressed gas.
D
DENT: A slight hollow in a surface, generally circular in
shape and having a low point near the center of the
circular area. The surface is not cut.
DEPOSITED METAL: Filler metal that has been added
during a welding operation.
B-6
TM 750-245-4
d. Electrolytic Oxygen-Hydrogen Generation The
conductors by which current enters and leaves the
water, which is decomposed by the passage of the
current.
e. Resistance Welding The part or parts of a
resistance welding machine through which the welding
current and the pressure are applied directly to the work.
FILM FAILURE: Failure of a lubricating film when the
load is so extreme at the point of maximum pressure as
to squeeze the film down to the point of boundary
lubrication.
ELECTRODE FORCE: a. Dynamic In spot, seam, and
projection welding, the force (pounds) between the
electrodes during the actual welding cycle.
b. Theoretical In spot, seam, and projection
welding, the force, neglecting friction and inertia,
available at the electrodes of a resistance welding
machine by virtue of the initial force application and the
theoretical mechanical advantage of the system.
c. Static In spot, seam, and projection welding, the
force between the electrodes under welding conditions,
but with no current flowing and no movement in the
welding machine.
FIRE POINT: The temperature at which the vapors
continue to burn when mixed with air and ignited.
FILTER GLASS: A colored glass used in goggles,
helmets, and shields to exclude harmful light rays.
FLAME CUTTING: See oxygen cutting.
FLAME GOUGING: See oxygen gouging.
FLAME HARDENING: A method for hardening a steel
surface by heating followed by a rapid quench.
FLAME SOFTENING: A method for softening steel by
heating with a gas flame followed by slow cooling.
FLASH: Metal and oxide expelled from a joint made by
a resistance welding process.
ELECTRODE HOLDER: A device used for mechanically
holding the electrode and conducting current to it.
FLASH POINT: The temperature at which the vapors
will ignite momentarily when mixed with air and exposed
to an open (open cup) or closed cup.
ELECTRODE SKID: The sliding of an electrode among
the surface of the work during spot, seam, or projection
welding.
FLASH WELDING: A resistance welding process in
which fusion is produced, simultaneously over the entire
area of abutting surfaces, by the heat obtained from
resistance to the flow of current between two surfaces
and by the application of pressure after heating is
substantially completed. Flashing is accompanied by
expulsion of metal from the joint.
EMULSIFICATION: The tendency of an oil to mix with
water.
ETCHING: A process of preparing metallic specimens
and welds for macrographic or micrographic
examination.
F
FACE OF WELD: The exposed surface of a weld, made
by an arc or gas welding process, on the side from
which welding was done.
FLASHBACK: The burning of gases within the torch or
beyond the torch in the hose, usually with a shrill,
hissing sound.
FACE SHIELD: A protective device to be worn on the
head for shielding the face and neck.
FLAT POSITION: The position in which welding is
performed from the upper side of the joint and the face
of the weld is approximately horizontal.
FATIGUE WEAR: Wear due to excessive use, surface
irregularities, and other defects. Often not due to
lubricant failure.
FLOC POINT: The floc point is the point (temperature)
at which wax crystals precipitate from a mixture of the
oil to be tested and a refrigerant.
FAYING SURFACE: That surface of a member that is in
contact with another member to which it is joined.
FILLER METAL: Metal to be added in making a weld.
FLOW BRAZING: A process in which fusion is produced
by heating with a molten nonferrous filler metal poured
over the joint until the brazing temperature is attained.
See brazing.
FILLET WELD: A weld of approximately triangular cross
section, as used in a lap joint, tie joint or corner joint,
joining two surfaces at approximately right angles to
each other.
FLOW WELDING: A process in which fusion is
produced by heating with molten filler metal poured over
the surfaces to be welded until the welding temperature
is attained and the required
B-7
TM 750-245-4
filler metal has been added. The filler metal is not
distributed in the joint by capillary attraction.
GROOVE: The opening provided between two members
to be joined by a groove weld.
FLUX: A cleaning agent used to dissolve oxides, release
trapped gases and slag and to cleanse metals for
welding, soldering and brazing.
GROOVE ANGLE: The total included angle of the
groove between parts to be joined by a groove weld.
GROOVE FACE: That surface of a member included in
the groove.
FOREHAND WELDING: A gas welding technique in
which the flame is directed against the base metal
ahead of the completed weld.
GROOVE RADIUS: The radius of a JF or UF groove.
FORGE WELDING: A group of welding processes in
which fusion is produced by heating in a forge or
furnace and by applying pressure or blows.
GROOVE WELD: A weld made by depositing filler
metal in a groove between two members to be joined.
GROUND CONNECTION: The connection of the work
lead to the work.
FREE BEND TEST: A method of testing weld
specimens without the use of a guide.
GROUND LEAD: See work lead.
FRETTING CORROSION: Corrosion caused by
vibration, high pressure, and oxidation. This results
when parts hold a load for a considerable period without
moving.
GUIDED BEND TEST: A bending test in which the test
specimen is bent to a definite shape by means of a jig.
H
FRACTURED SOLDER JOINT: This is the result of
allowing soldered components to move, while the solder
is in a plastic state. Looks similar to a cold solder joint,
however, close examination will show fatigue-like cracks
90 degrees to direction of movement.
HAMMER WELDING: A forge welding process.
HAND SHIELD: A device used in arc welding to protect
the face and neck. It is equipped with a filter glass lens
and is designed to be held by hand.
FULL FILLET WELD: A fillet weld whose size is equal to
the thickness of the thinner member joined.
HARD SURFACING: The application of a hard, wear
resistant alloy to the surface of a softer metal.
FURNACE BRAZING: A process in which fusion is
produced by the furnace heat and a nonferrous filler
metal having a melting point above 800 deg F, but
below that of the base metals. The filler metal is
distributed in the joint by capillary attraction.
HEAT AFFECTED ZONE: That portion of the base
metal whose structure or properties have been changed
by the heat of welding or cutting.
HEAT TIME: The duration of each current impulse in
pulsation welding.
FUSION: A thorough and complete mixing between the
two edges of the base metal to be joined or between the
base metal and the filler metal added during welding.
HEATING GATE: The opening in a thermal mold
through which the parts to be welded are preheated.
FUSION ZONE (FILLER PENETRATION): The area of
base metal melted as determined on the cross section
of a weld.
HELMET: A device used in arc welding to protect the
face and neck. It is equipped with a filter glass and is
designed to be worn on the head.
G
GAS POCKET: A weld cavity caused by the trapping of
gases released by the metal when cooling.
HOLDER SOLDERING IRON: A cage-like device to
dissipate heat from a soldering iron when not in actual
use for soldering operations. The holder prevents
overheating of soldering irons, thus preventing buildup
of oxides on the tips. This extends the life of the tip and
provides easier soldering iron maintenance.
GAS WELDING: A process in which the welding heat is
obtained from a gas flame.
GOGGLES: A device with colored lenses which protect
the eyes from harmful radiation during welding and
cutting operations.
HOLD TIME: The time that pressure is maintained at the
electrodes after the welding current has stopped.
GRAVITY: Weight per volume. The petroleum industry
uses the specific gravity or the API scales "Gravity is of
little significance as an index of the quality of oil."
HORIZONTAL WELD: A bead or butt welding process
with its linear direction horizontal or inclined at an
B-8
TM 750-245-4
angle less than 45 degrees to the horizontal, and the
parts welded being vertically or approximately vertically
disposed.
the work while an inert gas flows around the weld area
to prevent oxidation. No flux is used.
HORN: The electrode holding arm of a resistance spot
welding machine.
INTERPASS TEMPERATURE: In a multipass weld, the
lowest temperature of the deposited weld metal before
the next pass is started.
HORN SPACING: In a resistance welding machine, the
unobstructed work clearance between horns or platens
at right angles to the throat depth. This distance is
measured with the horns parallel and horizontal at the
end of the downstroke.
J
JOINT: That portion of a structure in which separate
base metal parts are joined.
JOINT PENETRATION: The maximum depth a groove
weld extends from its face into a joint, exclusive of
reinforcement.
HOT SHORT: A condition which occurs when a metal is
heated to that point, prior to melting, where all strength
is lost but the shape is still maintained.
K
HYDROGEN BRAZING: A method of furnace brazing in
a hydrogen atmosphere.
KERF: The space from which metal has been removed
by a cutting process.
HYDROMATIC WELDING: See pressure controlled
welding.
L
I
LAP JOINT: A joint between two overlapping members.
IMPREGNATED-TAPE METAL-ARC WELDING: An arc
welding process in which fusion is produced by heating
with an electric arc between a metal electrode and the
work. Shielding is obtained from decomposition of an
impregnated tape wrapped around the electrode as it is
fed to the arc. Pressure is not used, and filler metal is
obtained from the electrode.
LAYER: A stratum of weld metal, consisting of one or
more weld beads.
LEG OF A FILLET WELD: The distance from the root of
the joint to the toe of the fillet weld.
LOCAL PREHEATING: Preheating a specific portion of
a structure.
INDUCTION BRAZING: A process in which fusion is
produced by the heat obtained from resistance of the
work to the flow of induced electric current and by using
a nonferrous filler metal, having a melting point above
800 degrees F, but below that of the base metals. The
filler metal is distributed in the joint by capillary
attraction.
LOCAL STRESS RELIEF HEAT TREATMENT: Stress
relief heat treatment of a specific portion of a structure.
LUBRICANT BASE: The type of soap (sodium, lime,
lithium, lead, aluminum, etc.) used in the manufacture
of greases.
INDUCTION WELDING: A process in which fusion is
produced by heat obtained from resistance of the work
to the flow of induced electric current, with or without the
application of pressure.
M
MAGNETIC INDUCTION: Flux per unit cross-sectional
area, flux density.
INERT-GAS CARBON-ARC WELDING: An arc welding
process in which fusion is produced by heating with an
electric arc between a carbon electrode and the work.
Shielding is obtained from an inert gas such as helium
or argon. Pressure and / or filler metal may or may not
be used.
MASH SEAM WELDING: A seam weld made In a lap
joint in which the thickness at the lap is reduced
plastically to approximately the thickness of one of the
lapped joints.
MELTING POINT: The temperature at which a metal
begins to liquify.
INERT-GAS METAL-ARC WELDING (MIG): An arc
welding process in which fusion is produced by heating
with an electric arc between a metal electrode and the
work. Shielding is obtained from an inert gas such as
helium or argon. Pressure and/ or filler metal may or
may not be used.
MELTING RATE: The weight or length of electrode
melted in a unit of time.
METAL ARC CUTTING: The process of severing metals
by melting with the heat of the metal are.
INERT-GAS SHIELDED-ARC WELDING (TIG): An arc
welding process in which fusion is produced by heating
with an electric arc between a tungsten electrode and
METAL ARC WELDING: An arc welding process in
which a metal electrode is held so that the heat of the
arc fuses both the electrode and the work to form a
weld.
B-9
TM 750-245-4
METALLIZING: A method of overlay or metal bonding to
repair worn parts.
which the necessary cutting temperature is maintained
by means of an arc between an electrode and the base
metal.
MIXING CHAMBER: That part of a welding or cutting
torch in which the gases are mixed for combustion.
OXY-CITY GAS CUTTING: An oxygen cutting process
in which the necessary cutting temperature is
maintained by flames obtained from the combustion of
city gas with oxygen.
MULTI-IMPULSE WELDING: The making of spot,
projection, and upset welds by more than one impulse of
current. When alternating current is used each impulse
may consist of a fraction of a cycle or a number of
cycles.
OXY-HYDROGEN CUTTING: an oxygen cutting
process in which the necessary cutting temperature is
maintained by flames obtained by the combustion of
hydrogen with oxygen.
N
NEUTRAL FLAME: A gas flame in which the portion
used is neither oxidizing or reducing.
OXY-HYDROGEN WELDING: A gas welding process in
which the required welding temperature is attained by
flames obtained from the combustion of hydrogen with
oxygen.
NEUTRALIZATION NUMBER: The milligrams of
potassium hydroxide required to neutralize one gram (by
oil).
OXY-NATURAL GAS CUTTING: An oxygen cutting
process in which the necessary cutting temperature is
maintained by flames obtained from the combustion of
natural gas with oxygen.
NICK BREAK TEST: A method for testing the
soundness of welds by nicking each end of the weld,
then giving the test specimen a sharp hammer blow to
break the weld, then giving the test specimen a sharp
hammer blow to break the weld from nick to nick.
Visual inspection will show any weld defects.
NONFERROUS: Metals which contain
Aluminum, brass, bronze, copper and
nonferrous.
OXY-PROPANE CUTTING: An oxygen cutting process
in which the necessary cutting temperature is
maintained by flames obtained from the combustion of
propane with oxygen.
no iron.
lead are
OXYGEN CUTTING: A process of severing ferrous
metals by means of the chemical action of oxygen on
elements in the base metal at elevated temperatures.
NUGGET: The fused metal zone of a resistance weld.
OXYGEN GOUGING: An application of oxygen cutting
in which a chamfer or groove is formed.
O
OPEN CIRCUIT VOLTAGE: The voltage between the
terminals of the welding source when no current is
flowing in the welding circuit.
P
PASS: The weld metal deposited in one general
progression along the axis of the weld.
OVERHEAD POSITION: The position in which welding
is performed from the underside of a joint and the face
of the weld is approximately horizontal.
PEENING: The mechanical working of metals by means
of hammer blows. Peening tends to stretch the surfaces
of the cold metal, thereby relieving contraction stresses.
OVERLAP: The protrusion of weld metal beyond the
bond at the toe of the weld.
PENETRANT INSPECTION: a. Fluorescent. - A waterwashable penetrant with high fluorescence and low
surface tension. It is drawn into small surface openings
by capillary action. When exposed to black light the dye
will fluoresce.
b. Dye - A process which involves the use of three
non-corrosive liquids. First, the surface cleaner solution
is used. Then the penetrant is applied and allowed to
stand at least 5 minutes. After standing, the penetrant is
removed with the cleaner solution and the developer is
applied. The dye penetrant, which has remained in the
surface discontinuity, will be drawn to the surface by the
developer resulting in bright red indications.
OXIDIZING FLAME: A flame in which the oxygen
combines with all the acetylene or fuel available and
then the excess oxygen oxidizes the metal.
OXY-ACETYLENE CUTTING: An oxygen cutting
process in which the necessary cutting temperature is
maintained by flames obtained from the combustion of
acetylene with oxygen.
OXY-ACETYLENE WELDING: A welding process in
which the required temperature is attained by flames
obtained from the combustion of acetylene with oxygen.
PENTRATION CONSISTENCY: The distance a
standard-weight cone penetrates into a grease at a set
temperature.
OXY-ARC CUTTING: An oxygen cutting process in
B-10
TM 750-245-4
PERCUSSIVE WELDING: A resistance welding process in
which a discharge of electrical energy and the application
of high pressure occurs simultaneously or with the electrical
discharge occurring slightly before the application of
pressure.
PRE WELD INTERVAL: In spot, projection, and upset
welding, the time between the end of squeeze time and the
start of weld time or weld interval during which the material
is preheated. In flash welding, it is time during which the
material is preheated.
PERMANENT MAGNET: usually an iron alloy having a
high value of coercive force; that is, the magnetic domains
are not easily rotated. Thus, after the alloy has been
saturated by the application of a sufficiently large
magnetizing force, the domains tend to remain aligned
indefinitely, even after the magnetizing force has been
removed.
PROJECTION WELDING: A resistance welding process
between two or more surfaces or between the ends of one
member and the surface of another. The welds are
localized or predetermined points or projections.
PLUG WELD: A weld is made in a hole in one member of a
lap joint, joining that member to that portion of the surface
of the other member which is exposed through the hole.
The walls of the hole may or may not be parallel, and the
hole may be partially or completely filled with the weld
metal.
PUSH WELDING: The making of a spot of projection weld
in which the force is applied manually to one electrode and
the work or a backing bar takes the place of the other
electrode.
PULSATION WELDING: A spot, projection, or seam
welding process in which the welding current is interrupted
one or more times without the release of pressure or
PIT: A small circular indentation in a surface resulting from change of location of electrodes.
chemical action or corrosion.
PUNCTURE: A complete surface penetration, usually from
PITCH: Center to center spacing of welds.
a sharp object.
Q
QUENCHING: The sudden cooling of heated metal with oil,
POKE WELDING: A spot welding process in which water, or compressed air.
pressure is applied manually to one electrode. The other
electrode is clamped to any part of the metal much in the
R
same manner that arc welding is grounded.
REACTION STRESS: The residual stress which could not
otherwise exist if the members or parts being welded were
POROSITY: The presence of gas pockets or inclusions in isolated as free bodies without connection to other parts of
welding.
the structure.
POSITIONS OF WELDING: All welding is accomplished in REDUCING FLAME: See carburizing flame.
one of four positions: flat; horizontal; overhead or vertical.
The limiting angles of the various positions depend REGULATOR: A device used to reduce cylinder pressure
somewhat as to whether the weld is of a fillet or groove to a suitable torch working pressure.
type.
REINFORCED WELD: The weld metal is built up above
POSTWELD INTERVAL: In resistance welding, the heat the general surface of the two abutting sheets or plates in
time between the end of weld time, or weld interval, and excess of that required for the size of the weld specified.
the start of hold time. During this interval, the weld is
subjected to mechanical and heat treatment.
RESIDUAL STRESS: Stress remaining in a structure or
member as a result of thermal and / or mechanical
POUR POINT: The temperature at which an oil just ceases treatment.
to flow or pour.
RESISTANCE BRAZING: A brazing process in which
PREHEATING: The application of heat to a base metal fusion is produced by the heat obtained from resistance to
prior to a welding or cutting operation.
the flow of electric current in a circuit of which the work is a
part and by using a nonferrous filler metal having a melting
PRESSURE CONTROLLED WELDING: The making of a point above 800 degrees F, but below that of the base
number of spot or projection welds in which several metals. The filler metal is distributed in the joint by
electrodes function progressively under the control of a capillary attraction.
pressure sequencing device.
RESISTANCE BUTT WELDING: A group 'f resistance
PRESSURE WELDING: Any welding process or method in welding processes in which the weld occurs simultaneously
which pressure is used to complete the weld.
over the entire contact area of the parts being joined.
B-11
TM 750-245-4
RESISTANCE WELDING: A group of welding processes
in which fusion is produced by heat obtained from
resistance of the work to the flow of electric current in a
circuit of which the work is a part and by the application
or pressure.
or gouge as a result of a sharp instrument striking or
scraping the skin surface.
REVERSE POLARITY: The arrangement of direct
current arc welding leads in which the work is the
negative pole and the electrode is the positive pole of
the welding arc.
SEAM WELDING: Welding a lengthwise seam in sheet
metal either by abutting or overlapping joints.
SEAL WELD: A weld used primarily to obtain tightness
and to prevent leakage.
SELECTIVE BLOCK SEQUENCE: A block sequence in
which successive blocks are completed in a certain
order selected to create a predetermined stress pattern.
ROOT: See root of joint and root of weld.
ROOT CRACK: A crack in the weld or base metal which
occurs at the root of a weld.
SERIES WELDING: A resistance welding process in
which two or more welds are made simultaneously by a
single welding transformer with the total current passing
through each weld.
ROOT EDGE: The edge of a part to be welded which is
adjacent to the root.
SHEET SEPARATION: In spot, seam, and projection
welding, the gap surrounding the weld between fraying
surfaces, after the joint has been welded.
ROOT FACE: The prepared edge of a member to be
joined by a groove weld which is not beveled or
grooved.
SHIELDED WELDING: An arc welding process in which
protection from the atmosphere is obtained from a flux,
decomposition of the electrode covering, or an inert gas.
ROOT OF JOINT: That position of a joint to be welded
where the members approach closest to each other. In
cross section, the root of a joint may be a point, a line,
or an area.
SHOULDER: See root face.
ROOT OF WELD: The points, as shown in cross
section, at which the bottom of the weld intersects the
base metal surfaces.
ROOT OPENING: The separation between
members to be joined at the root of the joint.
SHRINKAGE STRESS: See residual stress.
SINGLE-IMPLUSE WELDING: The making of spot
projection and upset welds by a single impulse of
current. When alternating current is used, an impulse
may consist of a fraction of a cycle or a number of
cycles.
the
ROOT PENETRATION: The depth a groove weld
extends into the root of a joint measured on the
centerline of the root cross section.
SIZE OF WELD: a. Groove weld The joint penetration
(depth of chamfering plus the root penetration when
specified).
b. Equal leg fillet welds The leg length of the
largest right triangle which can be inscribed within the
fillet weld cross section.
c. Unequal leg fillet welds The leg length of the
largest right triangle which can be inscribed within the
fillet weld cross section.
d. Flange weld The weld metal thickness
measured at the root of the weld.
ROSEN JOINT: A pocket of rosen in a soldered
connection.
This occurs when insufficient heat is
applied to perform the soldering operation.
S
SAPONIFICATION NUMBER: The milligrams of
potassium hydroxide required to saponify (form soap)
one gram (of oil).
SATURATION: In a magnetic material, the condition
that exists when all magnetic domains are perfectly
aligned with the externally applied magnetic field. The
magnetic induction has reached its maximum possible
value.
SKIP SEQUENCE: See wandering sequence.
SCARF: The chamfered surface of a joint.
SLOT WELD: A weld made in an elongated hole in one
member of a lap or tee joint joining that member to that
portion of the surface of the other member which is
exposed through the hole. The hole may be open at
one end and may be partially or incompletely filled with
weld metal. (A fillet welded slot should not be construed
as conforming to this definition.) SLUGGING: Adding a
separate piece of pieces of material in a joint before or
during welding with a resultant welded joint that does
SLAG INCLUSION: Non-metallic solid material
entrapped in the weld metal or between the weld metal
and the base metal.
SCARFING: A process for removing defects and checks
which develop in the rolling of steel billets by the use of
a low velocity oxygen deseaming torch.
SCRATCH OR GOUGE: Surface skin damage in which
the metal has been displaced to the sides of the scratch
B-12
TM 750-245-4
not comply with design, drawing, or specification
requirements.
fusion is produced by heating with an electric arc drawn
between a metal stud, or similar part, and the other work
part, until the surfaces to be joined are properly heated.
They are brought together under pressure.
SOFT SOLDER: A composition of lead and tin (60-40)
that will melt within a heat range of 361 to 380 degrees.
This solder is desirable for repair of electronic
equipment because upon removal of heat reverts from
liquid to solid state almost instantly. Higher ratios of
lead to tin require more heat and remain in a plastic
state longer.
SUBMERGED ARC WELDING: An arc welding process
in which fusion is produced by heating with an electric
arc or arcs between a bare metal electrode or electrodes
and the work. The welding is shielded by a blanket or
granular, fusible material on the work>. Pressure is not
used, filler metal is obtained from the electrode, and
sometimes from a supplementary welding rod.
SOLDER POINTS: A peak of lead on a solder
connection. These result from excessive solder being
applied during the soldering operation.
SURFACING: The deposition of filler metal on a metal
surface to obtain desired properties or dimensions.
SPACER STRIP: A metal strip or bar inserted in the root
of a joint prepared for a groove weld to serve as a
backing and to maintain the root opening during
welding.
T
TACK WELD: A weld made to hold parts of a weldment
in proper alignment until the final welds are made.
SPATTER: The metal particles expelled during arc and
gas welding which do not form a part of the weld.
TEE JOINT: A joint between two members located
approximately at right angles to each other in the form
of a T.
SPOT WELDING: A resistance welding process in which
fusion is produced by the heat obtained from the
resistance to the flow of electric current through the
work parts held together under pressure by electrodes.
The size and shape of the individually formed welds are
limited by the size and contour of the electrodes.
TEMPER TIME: In resistance welding, that part of the
postweld interval during which a current suitable for
tempering or heat treatment flows. The current can be
single or multiple impulse, with varying heat and cool
intervals.
STAGGERED INTERMITTENT FILLET WELD: Two
lines of intermittent welding on a joint, such as a tee
joint, wherein the fillet increments in one line are
staggered with respect to those in the other line.
THERMAL SHUNT: Any metallic clamp device that is
placed ahead between a component and area of
soldering. Prevents overheating of delicate electronic
components.
STORED ENERGY WELDING: The making of a weld
with electric energy accumulated electrostatically,
electromagnetically, or electrochemically at a relatively
low rate and made available at the required welding
rate.
THERMIT CRUCIBLE: The vessel in which the thermit
reaction takes place.
THERMIT MIXTURE: A mixture of metal oxide and
finely divided aluminum with the addition of alloying
metals as required.
STRAIGHT POLARITY: The arrangement of direct
current arc welding leads in which the work is the
positive pole and the electrode is the negative pole of
the welding arc.
THERMIT MOLD: A mold formed around the parts to be
welded to receive the molten metal.
STRESS RELIEF HEAT TREATMENT: Uniform heating
of a structure or portion thereof to a sufficient
temperature, below the critical range, to relieve the
major portion of the residual stresses, followed by
uniform cooling. (Terms normalizing, annealing, etc.,
are misnomers for this application.) STRING BAND
WELDING: A method of metal arc welding on pieces 3 /
4 inch thick or heavier in which the weld metal is
deposited in layers composed of strings of beads
applied directly to the face of the bevel.
THERMIT REACTION: The chemical reaction between
metal oxide and aluminum which produces superheated
molten metal and aluminum oxide slag.
STUD WELDING: An arc welding process in which
THROAT DEPTH: In a resistance-welding
THERMIT WELDING: A group of welding processes in
which fusion is produced by heating with superheated
liquid metal and slag resulting from a chemical reaction
between a metal oxide and aluminum, with or without
the application of pressure. Filler metal, when used, is
obtained from the liquid metal.
B-13
TM 750-245-4
machine, the distance from the centerline of the
electrodes or platens to the nearest point of interference
for flatwork or sheets. In a seam-welding machine with
a universal head, the throat depth is measured with the
machine arranged for transverse welding.
the axis of the weld is approximately vertical. In pipe
welding, the pipe is in a vertical position and the welding
is done in a horizontal position.
VIBRATION BENDS: A turn or bend made into an
electrical lead to prevent vibrations from a harness or
cable being transmitted to electronic components.
THROAT OF FILLET WELD: a. Theoretical - The
distance from the beginning of the root of the joint
perpendicular to the hypotenuse of the largest right
triangle that can be inscribed within the filletweld cross
section.
b. Actual The shortest distance from the root of a
fillet weld to its face.
VISCOSITY: The distinguishing characteristic which
denotes the body or relative fluidity of a lubricating oil.
The heavier the oil, the higher its viscosity.
VISCOSITY INDEX: The viscosity of a petroleum oil
changes with temperature. The rate of change is
indicated by its viscosity index.
TOE CRACK: A crack in the base metal occurring at the
toe of the weld.
W
WANDERING BLOCK SEQUENCE: A block sequence
in which successive blocks are completed at random
after several starting blocks have been completed.
TOE OF THE WELD: The junction between the face of
the weld and the base metal.
TORCH: See cutting torch or welding torch.
WANDERING SEQUENCE: A longitudinal sequence in
which the weld bead increments are deposited at
random.
TORCH BRAZING: A brazing process in which fusion is
produced by heating with a gas flame and by using a
nonferrous filler metal having a melting point above 800
degrees F, but below that of the base metal. The filler
metal is distributed in the joint by capillary attraction.
WEAVE BEAD: A type of weld bead made with
transverse oscillation.
WEAVING: A technique of depositing weld metal in
which the electrode is oscillated.
It is usually
accomplished in a semicircular motion of the arc
terminal to the right and left of the direction of
deposition. Weaving serves to increase the width of the
deposit, decreases overlap, and assists in slag
formation.
TORQUE: A force that tends to set a body into rotation.
TRANSVERSE SEAM WELDING: The making of a
seam weld in a direction essentially at right angles to the
throat depth of a seam welding machine.
U
WELD: A localized fusion of metals produced by heating
to suitable temperatures. The application of pressure
and / or the use of filler metal may or may not be used.
The filler metal has a melting point approximately the
same or below that of the base metals, but always
above 800 degrees F.
UNDERBEAD CRACK-: A crack in the heat affected
zone not extending to the surface of the base metal.
UNDERCUTTING: An undesirable crater at the edge of
the weld caused by poor weaving technique or
excessive welding speed.
WELD BEAD: A weld deposit resulting from a pass.
UPSET: A localized increase in volume in the region of
a weld, resulting from the application of pressure.
WELD GAGE: A device designed for checking the
shape and size of welds.
UPSET WELDING: A resistance welding process in
which fusion is produced simultaneously over the entire
area of abutting surfaces, or progressively along a joint,
by the heat obtained from resistance to the flow of
electric current through the area of contact of those
surfaces. Pressure is applied before heating is started
and is maintained throughout the heating period.
WELD METAL: That portion of a weld that has been
melted during welding.
WELD SYMBOL: A picture used to indicate the desired
type of weld.
WELDING SYMBOL: The assembled symbol consists of
the following eight elements, or such of these as are
necessary: reference line; arrow; basic weld symbols;
dimension and other data; supplementary symbols;
finish symbols; tail; specification, process, or other
references.
UPSETTING FORCE: The force exerted at the welding
surfaces in flash or upset welding.
V
VERTICAL POSITION: The position of welding in which
B-14
TM 750-245-4
WELDING TIP: The tip of a gas torch especially
adapted to welding. " WELDING TORCH: A device
used in gas welding and torch brazing for mixing and
controlling the flow of gases.
WELDABILITY: The capability of a material to form a
strong bond of adherence under pressure or when
solidifying from a liquid.
WELDING LEADS: a. Electrode lead The electrical
conductor between the source of the arc welding current
and the electrode holder.
b. Work lead The electrical conductor between the
source of the arcwelding current and the work.
WELDING TRANSFORMER: A device for providing
current of the desired voltage.
WELDMENT: An assembly whose component parts are
formed by welding.
WELDING PRESSURE: The pressure exerted during
the welding operation on the parts being welded.
WICKING: Capillary action of liquid solder flowing along
a standed conductor. Wicking of solder under the
conductor insulation must be rejected.
WELDING ROD: Filler metal in wire or rod form used in
gas welding and brazing processes and in those arc
welding processes in which the electrode does not
provide the filler metal.
WORK LEAD: The electric conductor (cable) between
the source of arc-welding current and the work.
X
X-RAY: A test method used to detect internal defects in
a weld.
WELDING TECHNIQUE: The details of a manual,
machine, or semiautomatic welding operation which,
within the limitations of the prescribed joint welding
procedure, are controlled by the welder or welding
operator.
B-4. TABLE AND CHARTS
TABLE B-1
UNITS OF MEASURE
Giga
Mega
Kilo
Hecto
Deka
Metric System Prefixes
1,000,000,000
Deci
=
1,000,000
Centi =
1,000
Milli
=
100
Micro =
10
Nano =
Pico
=
=
=
=
=
=
1 centimeter
1 meter
1 kilometer
1 inch
1 foot
1 mil
=
=
=
=
=
=
Length
0.3937 inches
39.37 inches
0.62137 miles
2.54 centimeters
0.3048 meters
0.001 inch
1 sq cm
1 sq meter
1 sq kilometer
1 sq inch
1 sq foot
1 sq yard
1 sq mile
1 circular mil
1 sq inch
=
=
=
=
=
=
=
=
=
Square Measure
0.1550 sq in
1.196 sq yd
0.386 sq miles
6.452 sq centimeters
929.03 sq cm
0.8361 sq meters
2.59 sq kilometers
0.7854 sq mils
1,000,000 sq mils
B-15
0.1
0.01
0.001
0.000001
0.00000001
0.00000000001
=
=
=
0.0328 feet
1.0936 yards
3280 feet
=
10.784 sq ft
=
0.092903 sq meters
TM 750-245-4
TABLE B-1 (Continued}
Cubic Measure
1 cu centimeter
1 cu meter
1 gallon (U.S.)
1 cu foot
=
=
=
=
0.061 cu inch
1.308 cu yds
231 cubic inches
7.48 gallons
Time
1 day = 86,400 seconds
=
1 cu inch = 16.39 cu cm
35.316 cu feet
1 liter
=
1000 cu cm
1 year = 8760 hours (approx.)
Mass
1 slug
1 pound mass
=
=
32.2 pounds mass
453.6 grams
=
14,606 kilograms
Force
1 pound force
1 dyne
1 newton
1 pound force
1 newton
1 gram force
=
=
=
=
=
=
11 slug
1 gram
1 kilogram
4.452 newtons
100,000 dynes
980.6 dynes
Pressure
1 atmosphere
=
1 atmosphere
=
1 in Hg
=
Water pressure pounds/sq inch
1 erg
1 joule
1 ft lb
=
=
=
=
X 1 foot / sec / sec
X 1 centimeter / sec / sec
X 1 meter / sec / sec
=
0.224 pounds force
14.69 pounds/sq inch=29.92 in of Hg
76 cm of Hg=33.9 ft of water
0.491 pounds/sq inch
head in ft x 0.434
Work and Energy - Mechanical
1 dyne X 1 centimeter
1 newton X 1 meter = 105 dynes x 102 cm = 107 ergs
1 pound force X 1 foot = 1.356 joules
Work and Energy - Heat Equivalent
1 Btu raises 1 pound of water 10°F
1 gram calorie raises 1 gram of water 10°C
1 Btu = 252 gram calories = 778 ft lb = 1055 joules
1 gram calorie = 0.003964 Btu = 4.184 joules
1 horsepower hour = 2544 Btu
Work and Energy - Electrical Equivalent
1 joule = 1 watt X 1 second = 1 amp (dc) X 1 volt (dc) X 1 sec
W (joules) = ½ L (henries) X 1 (amperes)2
W (joules) = ½ C (farads) X E (volts)2
1 kilowatt hour
3,600,000 joules
Power
1 watt - 1 joule/ sec
1 horsepower - 550 ft lb/ sec - 746 watts
1 watt - 3.412 Btu / hr = 0.239 gram calorie/ sec
P (watts) -R (ohms) X 1 (amperes)2
R (ohms)
E (volts)2
P (watts)
B-16
TM 750-245-4
TABLE B-1 (Continued)
Angles
1 circle = 2π radians = 360 degrees
1 radian = 57.3 degrees 1 degree = 0.01745 radians
Geometric Figures
Circle, area of = D2 X 0.7854 = πr2
r = radius
Circle, circumference of = πD or 2 πr
Sphere, area of = πD2 = 4 πr2
D = diameter
3
Sphere, volume of = D X 0.5236 = 4/3 πr3
Triangle, area of = ½ altitude X base
Cone, volume of = area of base X 1/3 altitude
Trapezoid, area of = ½ (sum of parallel sides) X altitude
Pyramid, volume of = area of base X 1/3 altitude
TABLE B-2
TEMPERATURE CONVERSION TABLE
In left column find known temperature in degrees C. or F. Refer to corresponding C. or F. column for the equivalent.
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
1
2
3
4
5
6
7
8
9
100
11
12
13
14
15
16
17
18
19
20
Cent
-73.3
-67.8
-62.2
-56.7
-51.1
-45.6
-40.0
-34.4
-28.9
-23.3
-17.8
-17.2
-16.7
-16.1
-15.6
-15.0
-14.4
-13.9
-13.3
-12.8
-12.2
-11.7
-11.1
-10.6
-10.0
-9.44
-8.89
-8.33
-7.78
-7.22
-6.67
Fahr
-148
-130
-112
-94
-76
-58
-40
-22
-4
14
32
33.8
35.6
37.4
39.2
41.0
42.8
44.6
46.4
48.2
50.0
51.8
53.6
55.4
57.2
59.0
60.8
62.6
64.4
66.2
68.0
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
Cent
-6.11
-5.56
-5.00
-4.44
-3.89
-3.33
-2.76
-2.22
-1.67
-1.11
-0.56
0
0.56
1.11
1.67
2.22
2.78
3.33
3.89
4.44
5.00
5.56
6.11
6.67
7.22
7.78
8.33
8.89
9.44
10.0
10.6
Fahr
69.8
71.6
73.4
75.2
77.0
78.8
80.6
82.4
84.2
86.0
87.8
89.6
91.4
93.2
95.0
96.8
98.6
100.4
102.2
104.0
105.8
107.6
109.4
111.2
113.0
114.8
116.6
118.4
120.2
122.0
123.8
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
B-17
Cent
11.1
11.7
12.2
12.8
13.3
13.9
14.4
15.0
15.6
16.1
16.7
17.2
17.8
18.3
18.9
19.4
20.0
20.6
21.1
21.7
22.2
22.8
23.3
23.9
24.4
25.0
25.6
26.1
26.7
27.2
27.8
Fahr
125.6
127.4
129.2
131.0
132.8
134.6
136.4
138.2
140.0
141.9
143.6
145.4
147.2
149.0
150.8
152.6
154.4
156.2
158.0
159.8
161.6
163.4
165.2
167.0
168.8
170.6
172.4
174.2
176.0
177.8
179.6
TM 750-245-4
TABLE B-2 (Continued)
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
105
110
Cent
28.3
28.9
29.4
30.0
30.6
31.1
31.7
32.2
32.8
33.3
33.9
34.4
35.0
35.6
36.1
36.7
37.2
37.8
40.6
43
Fahr
181.4
183.2
185.0
816.8
188.6
190.4
192.2
194.0
195.8
197.6
199.4
201.2
203.0
204.8
206.6
208.4
210.2
212.0
221.0
230
120
130
140
150
160
170
180
190
200
210
212
220
230
240
250
260
270
280
290
300
Cent
49
54
60
66
71
77
82
88
93
99
100
104
110
116
121
127
132
138
143
149
Fahr
248
266
284
3-2
320
338
356
374
392
410
413
428
446
464
482
500
518
536
554
572
310
320
330
340
350
360
370
380
390
400
410
420
430
440
450
460
470
480
490
500
B-18
Cent
154
160
166
171
177
182
188
193
199
204
210
216
221
227
232
238
243
249
254
260
Fahr
590
608
626
644
662
680
698
716
734
752
770
788
806
824
842
860
878
896
914
932
TM 750-245-4
TABLE B-3
COLOR CODES
B-19
TABLE B-4
B-20
TM 750-245-4
TM 750-245-4
TABLE B-5
SOLDER ALLOY TEMPERATURE RANGES
Temperature
at which solder
becomes plastic
%Sn
0
5
10
15
20
25
30
35
38
40
45
48
50
55
60
63
65
70
75
80
85
90
95
100
95
35
27
40
50
61.5
62.5
96
95
0.75
%Pb
100
95
90
85
80
75
70
65
62
60
55
52
50
45
40
37
35
30
25
20
15
10
5
0
63
70
57
47
35.5
36.1
97.5
95
97.5
%Ag
%Sb
5
2
3
3
3
3
1.4
4
5
2.5
5
1.75
Temperature
at which solder
becomes liquid
C°
F°
272
224
183
183
183
183
183
183
183
183
183
183
183
183
Eutectic
183
183
183
183
183
183
183
522
435
361
361
361
361
361
361
361
361
361
361
361
361
232
187
179
179
179
179
Eutectic
Eutectic
221
Eutectic
305
Eutectic
450
369
354
354
354
354
361
361
361
361
361
361
361
430
581
C°
327
314
302
290
280
268
257
247
242
238
225
218
212
200
188
183
184
186
192
199
205
213
222
232
238
237
312
289
260
248
179
221
240
305
365
310
F°
620
59'
576
554
536
514
496
477
468
460
437
424
414
392
370
361
364
367
378
390
403
415
432
450
460
459
594
543
500
478
354
430
465
581
689
590
A eutectic alloy is that composition of two or more metals that has one sharp melting point and no plastic range. Sn-Tin;
Pb-Lead; Ag-Silver; Sb-Antimony.
B-21
TM 750-245-4
TABLE B-6. FUSES-STYLE, VOLTAGE RATING, CURRENT RATINGS AND CHARACTERISTICS
B-22
TM 750-245-4
INDEX
Paragraph
Page
A
Adhesive bonding:
Applying the adhesive................................................................................................................
Cleaning parts ...........................................................................................................................
Curing the adhesive...................................................................................................................
Final inspection..........................................................................................................................
General .....................................................................................................................................
Types of adhesive .....................................................................................................................
Application of lubricants:
General .....................................................................................................................................
Over-lubrication .........................................................................................................................
Under-lubrication .......................................................................................................................
Assembly components and circuit boards............................................................................................
Attaching hardware .............................................................................................................................
B
Batteries:
Electrolyte .................................................................................................................................
General .....................................................................................................................................
Inspection ..................................................................................................................................
Shelf life ....................................................................................................................................
Terminal ....................................................................................................................................
Test ...........................................................................................................................................
Blind nuts ............................................................................................................................................
Bonding:
Final inspection bonded joints....................................................................................................
Preparing parts to be bonded.....................................................................................................
Using fixtures in bonding............................................................................................................
9-6
9-5
9-7
9-9
9-3
9-4
9-2
9-1
9-2
9-2
9-1
9-1
10-3
10-4
10-5
3-34
4-2
10-1
10-1
10-1
3-20
4-1
3-24
3-23
3-28
3-26
3-25
3-27
4-15
3-18
3-18
3-19
3-18
3-18
3-18
4-4
9-9
9-5
9-7
9-2
9-1
9-2
C
Cable assemblies
Connectors ................................................................................................................................ 3-11c
Insulation ................................................................................................................................... 3-11b
Splicing...................................................................................................................................... 3-11a
Chassis assemblies:
Attaching hardware .................................................................................................................... 3-5
Dents and scratches .................................................................................................................. 3-6
Finish......................................................................................................................................... 3-8
General ..................................................................................................................................... 3-4
Identification .............................................................................................................................. 3-9
Weldments ................................................................................................................................ 3-7
Cleaning:
Facility....................................................................................................................................... 2-4
General ..................................................................................................................................... 2-3
Inspection .................................................................................................................................. 2-6
Processes.................................................................................................................................. 2-5
E
Electrical and electronic equipment:
Abbreviations............................................................................................................................. 3-2
Definition ................................................................................................................................... 3-2
General ..................................................................................................................................... 3-1
Terms ........................................................................................................................................ 3-2
Types of inspections:
Final................................................................................................................................. 3-3c
Initial or receiving ............................................................................................................. 3-3a
In-process ........................................................................................................................ 3-3b
I-1
3-2
3-2
3-2
3-1
3-1
3-1
3-1
3-1
3-1
2-1
2-1
2-1
2-1
3-1
3-1
3-1
3-1
3-1
3-1
3-1
TM 750-245-4
Paragraph
Electric motors ....................................................................................................................................
Electrical wiring:
Cable assemblies ......................................................................................................................
General .....................................................................................................................................
Inspection ..................................................................................................................................
Wiring harness assemblies ........................................................................................................
Electronic tubes ..................................................................................................................................
Page
3-30
3-19
3-11
3-10
3-13
3-12
3-31
3-2
3-2
3-5
3-2
3-19
F
Facilities:
Cleaning ....................................................................................................................................
Finishing....................................................................................................................................
Painting .....................................................................................................................................
Facilities for painting and finishing ......................................................................................................
Factors required for a successful workmanship standard program.......................................................
Final inspection painting and finishing .................................................................................................
Fuses ..................................................................................................................................................
2-4
2-8b
2-8a
2-8
1-8d
2-10
3-35
2-1
2-2
2-2
2-2
1-2
2-2
3-20
G
.........................................................................................................................................
1-5
1-1
4-16h
4-16c
4-16i
4-16b
4-16d
4-16e
4-16f
4-16g
4-16a
4-6
4-6
4-6
4-6
4.6
4-6
4-6
4-6
4-4
5-1
5-3
5-2
5-1
5-1
5-1
5-6
5-4
5-7
5-5
5-1
5-1
5-1
5-1
2-9
2-9b
2-9a
2-2
2-2
2-2
4-14
4-13
4-4
4-3
3-13
2-6
2-10b
2-10a
3-5
2-1
2-3
2-2
11-8
11-9
1-7
11-4
11-5
1-1
Glossary
H
Hardware inspection:
Bearings ....................................................................................................................................
Blind nuts...................................................................................................................................
Gears, belts, and pulleys............................................................................................................
Inserts........................................................................................................................................
Quick actin ................................................................................................................................
Rivet .........................................................................................................................................
Safety wiring..............................................................................................................................
Shims ........................................................................................................................................
Threaded components ...............................................................................................................
Hydraulic and pneumatic equipment:
General .....................................................................................................................................
Inspection or test .......................................................................................................................
Percussions during test..............................................................................................................
Hydraulic components:
Final inspection..........................................................................................................................
General .....................................................................................................................................
Identification ..............................................................................................................................
In-process inspection .................................................................................................................
In-process inspection...........................................................................................................................
Finishing....................................................................................................................................
Painting .....................................................................................................................................
Inserts:
Key type ....................................................................................................................................
Swaying type .............................................................................................................................
Inspection:
Cables and wiring harness assemblies.......................................................................................
Cleaning ....................................................................................................................................
Finishing....................................................................................................................................
Painting .....................................................................................................................................
Inspection procedures, preservation, packaging, and packing
Inspection points .................................................................................................................................
Storage inspection ..............................................................................................................................
Inspectors authority .............................................................................................................................
I-2
TM 750-245-4
Paragraph
Page
K
Key type inserts................................................................................................................................... 4-14
4-4
L
Lubrication
General .....................................................................................................................................
References ................................................................................................................................
Lubrication application
General .....................................................................................................................................
Over - lubrication .......................................................................................................................
Under - lubrication . ...................................................................................................................
Lubrication inspection procedure
Bearing......................................................................................................................................
Engines .....................................................................................................................................
Gears ........................................................................................................................................
General .....................................................................................................................................
Miscellaneous............................................................................................................................
Oil filters ....................................................................................................................................
Oil seal ......................................................................................................................................
Wire rope...................................................................................................................................
M
Magnesium, special Procedures
Cleaning ....................................................................................................................................
Facilities ....................................................................................................................................
Final inspection..........................................................................................................................
General .....................................................................................................................................
In-process inspection ................................................................................................................ .
Mechanical equipment
Attaching hardware ....................................................................................................................
"GO" gages for ..........................................................................................................................
Hardware inspection ..................................................................................................................
Introduction................................................................................................................................
"Not Go" gages for screw threads ..............................................................................................
Simplified rule for tap drill diameter ...........................................................................................
Tapping and thread cutting ........................................................................................................
Thread gage tolerance...............................................................................................................
Thread form...............................................................................................................................
Truncated setting plugs..............................................................................................................
Types of holes (tapping) ............................................................................................................
Unknown tap drill diameter ........................................................................................................
10-1
10-2
10-1
10-2
10-3
10-4
10-5
10-1
10-1
10-1
10-8
10-7
10-9
10-6
10-13
10-12
10-11
10-10
10-1
10-1
10-2
10-1
10-2
10-2
10-2
10-2
2-13
2-12
2-15
2-11
2-14
2-3
2-3
2-4
2-3
2-4
4-2
4-8
4-6
4-1
4-9
4-6
4-3
4-7
4-10
4-11
4-4
4-5
4-1
4-1
4-4
4-1
4-3
4-1
4-1
4-1
4-3
4-3
4-1
4-1
O
Objective of workmanship standard....................................................................................................... 1-8a
Optical equipment
Care and handling ..................................................................................................................... 6-2
Introduction................................................................................................................................ 6-1
Visual inspection........................................................................................................................ 6-3
P
Painting and finishing:
Facilities .................................................................................................................................... 2-8
Final inspection.......................................................................................................................... 2-10
General ..................................................................................................................................... 2-7
In-process inspection ................................................................................................................. 2-9
Plugs and jack assemblies
General ..................................................................................................................................... 3-17
Inspection criteria ...................................................................................................................... 3-18
I-3
1-2
6-1
6-1
6-1
2-2
2-2
2-1
2-2
3-18
3-18
TM 750-245-4
Paragraph
Pneumatic components
Final inspection.......................................................................................................................... 5-10
Operational test................................................................................................................ 5-10a
Visual inspection .............................................................................................................. 5-10b
General ..................................................................................................................................... 5-8
Identification .............................................................................................................................. 5-11
In-process inspection ................................................................................................................. 5-9
Potting, Embedding, and Sealing:
Apply the potting compound....................................................................................................... 9-13
Curing the potting compound ..................................................................................................... 9-15
Final inspection.......................................................................................................................... 9-16
General ..................................................................................................................................... 9-10
Preparing parts to be potted....................................................................................................... 9-11
Preparing the potting compound ................................................................................................ 9-12
Using fixtures in potting ............................................................................................................. 9-14
Preservation, Packaging, and Packing
Application of the levels of packing............................................................................................ 11-4
Containers ................................................................................................................................. 11-5
General ..................................................................................................................................... 11-1
Humidity indicators .................................................................................................................... 11-6
Levels of protection ................................................................................................................... 11-3
References ................................................................................................................................ 11-2
Preservation, Packaging, and Packing Inspection Procedures.
General ..................................................................................................................................... 11-7
Inspection points........................................................................................................................ 11-8
Storage inspection ..................................................................................................................... 11-9
Projects
Cleaning .................................................................................................................................... 2-5
Q
Quality control inspector's role.............................................................................................................
QC Inspector's standards ....................................................................................................................
1-6
1-8
R
References ......................................................................................................................................... 1-4
Report of equipment publication improvements................................................................................... 1-3
Responsibility of workmanship standards .............................................................................................. 1-8b
RF cables and waveguides
General ..................................................................................................................................... 3-14
RF cables ......................................................................................................................................... 3-15
Waveguides .............................................................................................................................. 3-16
S
Servo mechanisms
Final inspection..........................................................................................................................
General .....................................................................................................................................
Identification ..............................................................................................................................
In-process inspection .................................................................................................................
Soldering
General .....................................................................................................................................
Special tools and equipment ...............................................................................................................
Soldering acceptance and rejection criteria
Acceptance................................................................................................................................
Rejection criteria........................................................................................................................
Soldering comparison standards
Bificated terminals .....................................................................................................................
Components ..............................................................................................................................
Connector pins...........................................................................................................................
Cup connectors..........................................................................................................................
General .....................................................................................................................................
Hooked leads.............................................................................................................................
Insulation ...................................................................................................................................
I-4
Page
5-2
5-2
5-2
5-2
5-2
5-2
9-3
9-4
9-5
9-3
9-3
9-3
9-4
11-1
11-3
11-1
11-3
11-1
11-1
11-4
11-4
11-5
2-1
1-1
1-2
1-1
1-1
1-2
3-13
3-13
3-13
3-21
3-19
3-22
3-20
3-18
3-18
3-18
3-18
7-1
7-2
7-1
7-1
7-10
7-11
7-7
7-8
7-19
7-20
7-17
7-15
7-12
7-21
7-13
7-13
7-13
7-12
7-12
7-9
7-21
7-12
TM 750-2454
Paragraph
Printed circuit ...................................................................................................................................... 7-16
Stranded connection ........................................................................................................................... 7-14
Turret terminals................................................................................................................................... 7-18
Soldering inspection procedure
General ..................................................................................................................................... 7-3
Mechanical ................................................................................................................................ 7-5
Mechanical connections............................................................................................................. 7-9
Surveillance............................................................................................................................... 7-6
Thoroughness of inspection ....................................................................................................... 7-8
Visual inspection........................................................................................................................ 7-4
Workmanship standards ............................................................................................................ 7-7
Swaying type inserts ........................................................................................................................... 4-13
Switch and control............................................................................................................................... 3-32
T
Transformer ........................................................................................................................................ 3-33
W
Waveguides
Flexible...................................................................................................................................... 3-16b
Rigid ......................................................................................................................................... 3-16a
Welding
General ..................................................................................................................................... 8-1
Joining mechanism.................................................................................................................... 8-2
Preparation of metal for welding ................................................................................................ 8-3
Weld Inspection
Blow hole................................................................................................................................... 8-20
Cracked welds ........................................................................................................................... 8-17
Deformed welds......................................................................................................................... 8-18
Destructive inspection................................................................................................................ 8-25
Excessive setdown .................................................................................................................... 8-23
Excessive surface fusion ........................................................................................................... 8-22
General ..................................................................................................................................... 8-13
Insufficient weld......................................................................................................................... 8-24
Metal expulsion.......................................................................................................................... 8-19
Metallurgical examination .......................................................................................................... 8-26
Nondestructive inspection.......................................................................................................... 8-14
Offcenter welds.......................................................................................................................... 8-16
Open welds................................................................................................................................ 8.15
Pitted welds ............................................................................................................................... 8-21
Welds, Types Procedure
Arc welding................................................................................................................................ 8-5
Brazing ...................................................................................................................................... 8-9
Flow welding.............................................................................................................................. 8-10
Forge welding ............................................................................................................................ 8-8
Gas welding............................................................................................................................... 8-7
General ..................................................................................................................................... 8-4
Induction welding ....................................................................................................................... 8-12
Resistance welding .................................................................................................................... 8-11
Thermit welding ......................................................................................................................... 8-6
Wiring Harness Assemblies
Crimping......................................................................................................................................3-12c
Inspection .................................................................................................................................. 3-13
Lacing..........................................................................................................................................3-12d
Slicing .........................................................................................................................................3-12b
Stripping .................................................................................................................................... 3-12a
Workmanship Standards
Factor required for a successful workmanship standard program ................................................. 1-8d
How to met workmanship standards............................................................................................. 1-8d
Objective ................................................................................................................................... 1-8a
Personnel .................................................................................................................................... 1-8c
Responsibility .............................................................................................................................. 1-8b
I-5
Page
7-12
7-12
7-13
7-1
7-1
7-2
7-1
7-1
7-1
7-1
4-3
3-19
3-19
3-13
3-13
8-1
8-2
8-2
8-6
8-5
8-6
8-7
8-7
8-6
8-4
8-7
8-6
8-8
8-5
8-5
8-5
8-6
8-2
8-4
8-4
8-3
8-3
8-2
8-4
8-4
8-3
3-3
3-5
3-3
3-3
3-3
1-2
1-2
1-2
1-2
1-2
TM 750-245-4
By Order of the Secretary of the Army:
Official:
KENNETH G. WICKHAM,
Major General, United States Army,
The Adjutant General.
W. C. WESTMORELAND,
General, United States Army,
Chief of Staff.
DISTRIBUTION:
To be distributed in accordance with DA Form 12-32 (qty rqr Block # 1), General information applicable to ALL
organization which have a missile, rocket and / or AD mission.
U.S. GOVERNMENT PRINTING OFFICE: 1995 - 633-072/20156
The Metric System and Equivalents
Linear Measure
Liquid Measure
1 centiliter = 10 milliters = .34 fl. ounce
1 deciliter = 10 centiliters = 3.38 fl. ounces
1 liter = 10 deciliters = 33.81 fl. ounces
1 dekaliter = 10 liters = 2.64 gallons
1 hectoliter = 10 dekaliters = 26.42 gallons
1 kiloliter = 10 hectoliters = 264.18 gallons
1 centimeter = 10 millimeters = .39 inch
1 decimeter = 10 centimeters = 3.94 inches
1 meter = 10 decimeters = 39.37 inches
1 dekameter = 10 meters = 32.8 feet
1 hectometer = 10 dekameters = 328.08 feet
1 kilometer = 10 hectometers = 3,280.8 feet
Square Measure
Weights
1 sq.
1 sq.
1 sq.
1 sq.
1 sq.
1 sq.
1 centigram = 10 milligrams = .15 grain
1 decigram = 10 centigrams = 1.54 grains
1 gram = 10 decigram = .035 ounce
1 decagram = 10 grams = .35 ounce
1 hectogram = 10 decagrams = 3.52 ounces
1 kilogram = 10 hectograms = 2.2 pounds
1 quintal = 100 kilograms = 220.46 pounds
1 metric ton = 10 quintals = 1.1 short tons
centimeter = 100 sq. millimeters = .155 sq. inch
decimeter = 100 sq. centimeters = 15.5 sq. inches
meter (centare) = 100 sq. decimeters = 10.76 sq. feet
dekameter (are) = 100 sq. meters = 1,076.4 sq. feet
hectometer (hectare) = 100 sq. dekameters = 2.47 acres
kilometer = 100 sq. hectometers = .386 sq. mile
Cubic Measure
1 cu. centimeter = 1000 cu. millimeters = .06 cu. inch
1 cu. decimeter = 1000 cu. centimeters = 61.02 cu. inches
1 cu. meter = 1000 cu. decimeters = 35.31 cu. feet
Approximate Conversion Factors
To change
To
inches
feet
yards
miles
square inches
square feet
square yards
square miles
acres
cubic feet
cubic yards
fluid ounces
pints
quarts
gallons
ounces
pounds
short tons
pound-feet
pound-inches
centimeters
meters
meters
kilometers
square centimeters
square meters
square meters
square kilometers
square hectometers
cubic meters
cubic meters
milliliters
liters
liters
liters
grams
kilograms
metric tons
Newton-meters
Newton-meters
Multiply by
To change
2.540
.305
.914
1.609
6.451
.093
.836
2.590
.405
.028
.765
29,573
.473
.946
3.785
28.349
.454
.907
1.356
.11296
ounce-inches
centimeters
meters
meters
kilometers
square centimeters
square meters
square meters
square kilometers
square hectometers
cubic meters
cubic meters
milliliters
liters
liters
liters
grams
kilograms
metric tons
To
Newton-meters
inches
feet
yards
miles
square inches
square feet
square yards
square miles
acres
cubic feet
cubic yards
fluid ounces
pints
quarts
gallons
ounces
pounds
short tons
Temperature (Exact)
°F
Fahrenheit
temperature
5/9 (after
subtracting 32)
Celsius
temperature
°C
Multiply by
.007062
.394
3.280
1.094
.621
.155
10.764
1.196
.386
2.471
35.315
1.308
.034
2.113
1.057
.264
.035
2.205
1.102
PIN: 014036-000
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