AO-935-Knife-shapern.. - Science

 8. REMOYE KNIFE CAREFULLY
At the end of the time cycle, the knife holder will stop in
raised, horizontal position. Loosen clamp screws and
remove knife. As a safety precoution and for ease of
handling, use knife handle.
NOTE If the holder should stop upside down (knife
clomps facing downward), turn the automatic
time knob beyond the 10 minute setting. Wait
until the knife starts to move upward and then
turn timer to “zero”. The knife holder will then
go through a half cycle and stop in correct,
raised position.
9. CLEAN KNIFE —— INSPECT CONDITION
Wipe knife with clean cloth moistened with solvent and
inspect the cutting facet under o microscope (100%).
Keeping in mind that the coarse honing action proceeds
from the back of the facet to the edge of the knife, check
to see how much of the surface has been honed. As a
guide, refer to the actual photographs, shown here, taken
during various stages of coarse honing. Because each
knife and its condition is different, no specific time can
be given to achieve the results illustrated.
— "522 as
| 10. CLEAN GLASS PLATE —— CONTINUE COARSE
| HONING
| Wash the glass hone plate with a detergent under hot
running tap water to remove abrasive and fine metal parti-
cles. Wipe dry. Apply fresh, coarse abrasive and continue
honing as required. Inspect periodically to check progress.
Add obrosive as needed. Wash hone plate when abrasive
becomes a dirty, grayish color.
With experience you'll soon be able to determine when you
have a good, even coarse facet, uniform in appearance and
have completely removed the single, factory facet - or - the
FIGURE C:
Appearance of a new AD
knife or knife Factory reconditioned by
American Optical before use.
there is just o single cutting
fine, second, cutting facet produced by the 935 Sharpener.
NOTE: When a “shiny” surface is worn on the face of the hone plate, see instructions for dressing
plate to restore even, frosted surface, poge 11.
FIGURE D: Shown here is o new or FIGURE E: l[lustrated above is an
reconditioned AD knife after normal use. “intermediate” stage in the coarse
Close inspection reveals knicks in the honing cycle. Notice the relatively
edge of sufficient size (over 3-4 microns) large area near the knife edge which
to require coarse honing. still remains to be coarse honed.
FIGURE F: An "odvanced'’ stoge in the
comse hening cycle is pictured here.
Haning has progressed clese to the edge
of the knife, leaving only @ small surface
area still to be honed.
FIGURE ©: Coarse honing complete.
Mate the even width and uniform appear ——
ance of the entire cutting facet, without
any trace of original surface chôracter-
istics, Knife is now ready for fine
hening.
SMALL NICKS OF 3-4 MICRONS OR LESS WILL BE REMOYED DURING FINE HONING.
ill. FINE HONING OPERATION
Coarse honing must be followed by a final honing pro-
cess using fine abrasive. As illustrated in figure H,
the coarse honing action produces a single facet. In
proceeding with the fine honing operation, a second
cutting facet is ground on the knife ot the cutting edge
as shown in figure |.
The width of the fine facet is not of significance.
This will vary from one knife to the next. Also, this
width often varies from one side of a particular knife
to the other: however, this fine facet should be ap-
proximately the same width from ene end of the knife
to the other end. (See page 14 for comments on typical
sharpening problems.)
While the above should be kept in mind, the most
critical factor in judging the success of fine honing
is the degree to which the small, remaining nicks are
removed. Nothing exceeds this in importance! Ex
actly how microscopically free of nicks the knife edge
FIGURE H |
FIGURE |
must be depends, of course, on the thickness of the
tissue sections being cut. For example, with a four-
micron nick in the knife, you connot obtain a satis-
factory section 5 microns thick because of a “tearing”
action. However, with a 10 micron section, results
may be acceptable although not uniformly even.
Your AQ 935 Sharpener, with proper fine honing pro-
cedure, is capable of producing an edge so near to
perfection that subsequent hand stropping will only
result in “turning over” the edge. Do not strop!
NOTE Full
some steps are similar to those performed
during coorse honing, and are therefore ab-
breviated, watch closely for the” differences”
in technique. Nicks should not be more than
3-4 microns deep if the fine honing operation
is to be properly accomplished. Inspect con-
dition using a microscope.
Follow fine honing procedure carefully. While
1. CHECK FOR CLEANLINESS
It is extremely essential that all traces of coarse abrasive
are removed from the knife, knife holder and 91055 Попе
plate before beginning fine honing. Check ond clean thor-
oughly. If the same glass hone plate is to be used, remove
and wash under hot running tap water using ordinary deter-
gent and carefully wipe dry.
2. PUT GLASS HONE PLATE IN LOWER POSITION
After making sure that the frosted hone plate surface does
not have a “shiny” worn area, put the plate in the lower
hone table position. Squeeze to raise plunger. Ploce left
end of plate on the lower pad of the plunger unit and insert
right end into the lower “Y” of the plate support block.
Release plunger and slide plate slightly from front to back
to assure proper plate alignment in “Y”.
10
3. ATTACH AND CENTER KNIFE
Install knife so that the end with the AO trade mark is to
your right (handle slot to left). Temporarily tighten the two
screws and center the knife carefully using a ruler. Make
sure that the knife is snug against the back of holder and,
alternately, tighten clamp screws until knife is held in
place. Mote: Always sharpen longest knives first.
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4. SHAKE AND APPLY FINE ABRASIVE
Check to moke certain that you are using the Fine Abrasive,
No. 938. Shake very thoroughly until all particles are in
suspension. (Stir, if necessary.) Apply o narrow “ribben’’
of fine abrasive on the gloss plate the some length as the
knife. Apply fine abrasive about an inch inside front edge
of glass plate.
5. SET TIMER FOR THIRTY MINUTES
Use an initial time setting of at least 30 minutes when be-
ginning fine honing operation. Keep Plexiglass cover
closed when instrument is running. At the end of the time
cycle, loosen clamp screws and remove knife. Às a safety
precaution, and for ease of handling, use knife handle.
6. CLEAN KNIFE, INSPECT CONDITION
Clean knife edge with clean cloth moistened with solvent
such as xylene and inspect under o microscope (100Х).
The second, fine cutting facet, characteristic of the AO 935
Sharpener, will be apparent. Look carefully for presence
and size of any small nicks still evident in the knife edge.
The removal of such nicks == not the width of fine facet --
determines your progress,
7. CONTINUE FINE HONING, AS REQUIRED
In proceeding with fine honing, “timing” is dependent en-
tirely upon the condition of the knife. Experience with the
935 will soon enable you to gauge approximately how much
more time is needed to achieve the desired results; how-
ever, please remember that microscopic examination is still
the final determining factor. Add abrasive, as required.
Should fine abrasive become “'grayish” in color, this indi-
cates the presence of excess metal particles. In this case,
wash hone plate and apply fresh abrasive.
FIGURE J): Appearance of an AD knife
edge öfter proper coarse honing. Mote
that there is just e single facet, the
surface of which is evenly ground and
uniform in oppearonce.
FIGURE К: Nlustrated here is an
“initial” stoge in the fine honing cycle.
The second cutting facet is beginning to
become evident near the edge of the
knife
FIGURE L: The fine facet is now
clearly opparent in this “advance” stage
photograph. In contrast to coarse honing,
the fine honing action procesds from the
Font edge of the knife to the back.
FIGURE M: Fine honing complete. Note
the even width ef the fine facet (from
end to end of knife). Small nicks hove
bean satisfacterily removed. Ми сга-
scopic "'S-shaped”” lines on fine facet
ore a Normal result of polishing octien
ond do not affect cutting qualities,
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8. AFTER FINE HONING IS COMPLETE
Clean knife and wipe dry carefully. Where atmosphere is
corrosive and the knife is to be stored for any length of
time, lubricate with a good grade of light, neutral oil.
After the knife has been used, only a “touch up” of the
edge using fine honing may be sufficient to restore cutting
qualities. (Never strop.) Much will depend upon the type
of tissue and desired thickness of the sections. Again,
microscopic examination will assist you in determining
what is necessary.
FIGURE J FIGURE K
FIGURE L FIGURE M
IV. DRESSING HONE GLASS PLATES
The honing action of the knife against the frosted
surface of the glass plate will eventually cause a
“shiny” path to be worn on the face of the plate as
wide as the length of the knife. (The number of hours
before the appearance of a shiny area depends upon
the type of abrasive most frequently used.)
When such a rectangular-shaped, shiny surface ex-
ists, time required for proper honing increases sub-
stantially. Coarse honing, in particular, becomes
very time consuming. Also, should one attempt to
sharpen a knife that is longer than the worn part of
the plate, correct honing becomes impossible. The
ends of the longer knife will ride high on microscopic
shoulders [areas still frosted) and the center will not
make proper contact on the shiny, worn area.
To economize time, most technicians wait until both
glass hone plates require dressing. In addition, if
desired, each side of the two plates can be dressed
during the some procedure thus restoring the frosted
appearance to all four identical plate surfaces.
11
12
NI : > 2
CIN A A
7
1. MAKE CERTAIN HONE PLATES ARE CLEAN
Check to see that hone plates are entirely free of any
trace of either coarse or fine abrasive. Clean under
running tap water, using detergent if necessary.
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3. APPLY HONE GLASS DRESSING COMPOUND
Remove cap and use plastic bottle like a “salt
shaker” to apply the No. 939 dressing powder. Ap-
ply in a fairly thin, even layer over the entire sur-
face of the glass plate.
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5. AFTER 6-8 CIRCULAR MOTIONS ‘‘FLIP”’
PLATES
When you complete from six to eight full, circular
motions, flip both plates over together (as a '‘sand-
wich‘) so that the bottom plate becomes the top
plate. Repeat circular, stroking action and flipping
procedure for about 5 minutes. Add honeglass powder
and water as needed.
NOTE The appearance of large “bubbles” between
the plates and the feeling of less friction
‘drag are both indications that additional
honeglass dressing compound and water are
required.
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2. PLACE "SHINY" SIDE UP —- SPRINKLE WITH
WATER
After rinsing, place the damp glass hone plate on the
sponge-like, polyurethane pad. Position so that the
side with the worn area faces Cup” and liberally
sprinkle droplets of water on the surface.
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4. RUB TOGETHER USING A CIRCULAR MOTION
Place the second, clean glass plate (‘“shiny’” side
down) over the first plate. Rub one surface against
the other with a circular or slightly elliptical motion.
Use both hands and maintain steady, light pressure.
NOTE If plates tend to stick together stubbornly,
an excess of honeglass compound may have
been applied. Add more droplets of water
and continue rubbing action. Any excess
will quickly “work” off the edges of the
plates.
6. DO HOT OVERLAP PLATES BY MORE THAN
OME INCH
Watch carefully that you do not overlap the top plate
more than an inch beyond the edge of the bottom plate
during circular motion action. |f plates are over-
lopped excessively during dressing, edges may be
rounded slightly and microscopic concave areas will
be rubbed into the top glass plate.
7. WASH PLATES —— INSPECT CONDITION
After dressing for approximately five minutes, wash
each plate thoroughly under running water and dry
completely. Inspect for uniform, frosted appearance
over the entire surface of each plate. |f there is a
"shadowy"" indication of the shiny area still present
repeat the above procedure until a uniform surface is
obtained.
y
8. TEST GLASS HONE PLATES FOR “FLATNESS”'
After plates are properly dressed and dried, they can
be tested for flatness in the following manner: Bring
the plates into contact [dressed surfaces together)
with a sliding, circular motion until edges match.
Lift the top plate with your fingertips. If both plates
are perfectly flat, the bottom plate will cling to the
top plate and raise with it, about 14", until ¡ts own
weight finally pulls it free.
CAUTION All traces of hone glass dressing compound
must be removed from gloss plates before
sharpening knives.
SURFACE MUST BE FACTORY GROUND TO RESTORE PROPER BEVEL WIDTH
FIGUREN
When ... Why AO Factory Reconditioning of Knives is Required
The new, or factory reconditioned, AÛ Knife has
very precise wedge and cutting facet angles. These
angles permit the knife to meet’ the glass hone
plate in the correct manner for proper coarse and
fine honing. For this reason, please remember:
A. The use of only new or factory reconditioned AQ
Knives in good condition is recommended. In a
very few instances (where angles and configure-
tion are similar) competitive knives may be
sharpened on the 935. Even in these cases, AC
does not guarantee optimum results. Hollow
ground knives of any type simply cannot be sharp-
ened satisfactorily on the 935.
B. If your AQ Knives hove been sharpened by any
other method, they must be reconditioned by
American Optical to restore proper ongles prior
to sharpening on the 935.
Reconditioning
C. AD Knives with nicks larger than 10-12 microns in
the area of the knife used for sectioning should,
as a general rule, be factory reconditioned.
D. After many repeated sharpenings, the angles of
coarse and fine honed cutting facets will widen
excessively. At that time, the knife should be
sent to the factory where the entire knife thick-
ness will be ground down slightly to restore pro-
per angle, as illustrated in figure N.
Knives which, by sharpening or recondition-
ing, have eventually been reduced in size
(from back to cutting edge) to 27mm or less
cannot he resharpened on the AQ 935 Knife
Sharpener nor can they be factory recondi-
tioned.
NOTE
American Optical Company
Instrument División
Buffalo, N.Y. 14715
Attention: Repair Department
13
14
Appearance
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NOTE: These ore typical knife sharpening problems that may
TYPICAL KNIFE SHARPENING PROBLEMS
Problem
Fine facet fades out at
ends of knife (opposite
side of knife has even
bevel].
ar
Fine focet fades aut at
center of knife (opposite
side of knife has even
bevel],
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Fine facet starts back of
(away from) cutting edge.
| No fine facet in center
area of knife. [This
condition will occur on
both sides of knife.)
Cause
Microscopic curvature on
ane side of knife.
1. Facet angle too wide
(see page 13, fig-
ure N 1.
2. Insufficient coarse
honing. (Microscopic
examination would
have revealed this.)
3. Knife accidental ly
reversed (end for
end) in holder.
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Sharpening knives of
different length on some
glass plate in improper
sequence.
Correction
Disconnect tuming
mechanism and coarse
hone side of knife with
vneven bevel for one
hour. (Contact your AQ
representative for
specific instructions to
accomplish this step.)
Caution: Microswitch
will not shut off when
used in this manner.
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— | == — —
1. Recondition at
factory.
2. Coarse hone.
J. Repeat coarse
honing cycle with
knife in proper
position.
Redress, or change,
hone plate and start
complete cycle with
coarse honing. [Always
sharpen longest knives
first.)
be encountered. Should
you ever experience an unusual sharpening situation in which you cannot identify
the problem, write the AQ Sales Department at Buffalo for prompt assistance.
MAINTENANCE
The AO Microtome Knife Sharpener is of durable соп-
struction with remarkable design simplicity.
Except
for routine cleaning and occasional lubrication, ne
other maintenance should be required.
Even after
years of use, only a few parts are likely to need re-
placement. These are listed on page 15.
Should the occasion ever arise, the AO 935 Sharpener
can be reconditioned at the American Optical plant
in Keene, Mew Hampshire.
This is a customer ser-
vice provided at a nominal charge.
1. CLEANING: Plexiglass cover and outside enam-
eled surfaces should be kept clean.
Use warm
water and detergent. Sponge out and wipe dry the
catch-basin on the hone table after each sharp-
ening session. Knife holder, knife holder shoft
and exposed fittings are non-corrosive and re-
quire no attention other than normal cleaning.
2. LUBRICATION:
Lubricate instrument approxi-
mately once each month, depending on how ex
tensively it is used.
used throughout the instrument; therefore,
are
only a few points require lubrication.
Place just a drop or two of Pike
sparingly.
oil on:
(1)
(2)
two
Lifetime Oilite bearings
| ubricate
round, felt pad beneath worm gear of motor.
brass bearings at pivot points between
carrier arm assembly and slide casting.
(3)
(4)
brass bearing at the end of the motor crank
arm.
two slide rods (Use Molykote Spray Graphite
Lubricant - available locally).
ET Model 935 PARTS LIST
Pic. Id. Part No. Description
(A) 935-147 Solenoid 115Y, 600
(B) 935-176 Timer
(С) 935-503 Knife Carrier Actuator Assembly
(for instruments with Serial No.
aver 3,000). Order L5137 Knife
Carrier Actuator Kit for instruments
with Serial No. under 3,000.
(D} 935-860 Side Plate Assembly
(includes motor)
(E) 935-863 Knife Holder (for instruments
with Serial No. over 3,000)
(Е) 935-868 Microswitch Kit
NOTE: All parts are interchangeable with old style (Serial No. under 3,000)
FOR AQ Sharpener except as noted.
In the event that repair or reconditioning is ever required,
FACTORY SERVICE send instrument directly to:
CUSTOMER SERVICE DEPARTMENT
AMERICAN OPTICAL COMPANY
KEENE, NEW HAMPSHIRE
Sales Department
All correspondence related AMERICAN OPTICAL COMP ANY
to repairs and other matters нЕ ро
should be directed to: Sugar and Eggert Roads
— Less Buffalo, New York 14215
15
Model 935 Knife Sharpener
Accessories and AO Microtome Knives
Number Description
736 Glass Hone Plates (Set of 2)
937 Coarse Abrasive (package of 6
plastic bottles)
738 Fine Abrasive (package of 6
plastic bottles)
939 Honeglass Compound (package
of 6 plastic bottles)
935-105 Redressing Pad
935-139 Knife Inspection block (wood)
940 110mm Knife in Case
947 120mm Knife in Case
945 185mm Knife in Case
255 Handle for 940, 947 and 945
769 Pike Cil (3oz.)
o AMERICAN OPTICAL COMPANY
> INSTRUMENT DIVISION «+ BUFFALO. N. Y. 14215
INSTRUMENT DIVISION SALES OFFICES:
Atlanta - Boston - Chicago - Cincinnati - Cleveland - Dallas - Detroit - Houston -
Los Angeles - Memphis - Minneapolis - New York - Philadelphia - Pittsburg -
Sacramento - St. Louis - San Francisco - Seattle - Toronto - Washington -
International Division: Southbridge, Mass.
935-101 8/66 Printed in USA,
REFERENCE MANUAL
AO Model 935
Automatic Microtome Knife Sharpener
= ERS Ta ыы вом АБ [бес вл QFTH AL CHEFART
QG AMERICAN OPTICAL COMPANY
INSTRUMENT DIVISION = BUFFALO, NEW YORK 14215
TABLE OF CONTENTS
Preliminary Steps , ©. 2 2 2 a 12 « + Page J
Microscopic Examination . . . . . . . . Page 5
Coarse Honing Operation , , , . . . . . Page 6
Fine Honing Operation , , , , . . . . . Page %
Dressing Hone Glass Plates |, . . _ . . . Fage 11
Factory Reconditioning . . . . . . . . . Page 13
Typical Sharpening Problems . . . . ... Page 14
Maintenance. LE 1. 15555 Page 14
Fortefiet: 2 202 2 An Page 15
Accessories and Knives . . . . a . Back Cover
“Get Acquainted” with your AD 935 and its accessories
The 935 Knife Sharpener is shipped complete with all
accessories required for coarse and fine knife honing
and, when required, to dress glass hone plate sur-
faces. It employs the some sharpening principles
designed into the elaborate, custom-built sharpening
equipment used in the production of the Microtome
Knives.
1. COARSE ABRASIVE -- 2 BOTTLES: Clearly
labeled. Unbreakable plastic bottles for handy,
sate application. Used in coarse honing pro-
cedure. (Shake well before using.)
2. FINE ABRASIVE -- 2 BOTTLES: Clearly la-
beled. Used in the final sharpening (fine honing]
rocedure. Safe, unbreckable plastic bottles.
Shake well before using. }
3. HONE GLASS COMPOUND -- 2 BOTTLES: Dry
powder dressing compound which can be easily
dispensed onto glass plates. Clearly labeled.
Because there are many demands on your time, take
a few minutes now to get acquainted with your AD
equipment to speed and simplify knife sharpening
later. In addition to the plug adapter to permit use of
a two-prong, grounded, electrical outlet, the following
is included with Model 935.
4. TWO GLASS HOME PLATES: The 2 glass hone
plates supplied with the 935 Sharpener are iden-
tical. Both sides of each plate are the same,
giving you four usable honing surfaces.
5. REDRESSING PAD: Washable, polyurethane pad
on which glass hone plates are placed when
plates ore dressed (restored).
6. KNIFE INSPECTION BLOCK (WOOD): Hardwood
block used to hold knife blade at proper angle to
inspect cutting facet with microscope.
Just a few, fast preliminary steps and the AO 935 is “Ready to Use”
1. Place the instrument on a solid, level table or
laboratory bench and remove tags and retaining
tape Fees shipment.
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3. Lift the entire cover housing up and simulta-
neously move slightly toward the rear. This
will free the housing from the two positioning
pins at the back of the instrument bose. Watch
the position of the hone plate plunger to avoid
damaging.
5. Place a drop or two of Pike oil on the felt pad
beneath the motor worm gear. No other initial
lubrication is required. Replace housing and
tighten thumb screw firmly.
2. To remove the two, wood shipping blocks inside
the instrument, first loosen the lorge thumbscrew
directly under the front end of the 735.
uu.
4. Remove the two red blocks, as shown, by pulling
the shipping tape free.
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6. To attach the knife holder to the knife carrier
arm, turn the arm, by hand, so that the pin is
vertical. Position the knife holder so that the
blade clamps are “up.”
7. Slide the knife holder onto the shoft until the
“slot” in the holder is seated firmly against the
pin. Tighten locking serew securely.
CAUTION De not operate instrument without knife in holder ...
8. Attech plug adopter if required. Check to see
that switch is “off” and plug in instrument.
to do so may cause damage.
EHIFF CLAMP SCREWS wy,
FLATE
POSITIONING =———
PLUNGER
CLASS MONE PLATE
LOCKSCR FW
Your technical skill...
...is the key to the successful performance of any
laboratory equipment. While the AD Micretome Knife
Sharpener is a simple, compact instrument, your
technical knowledge plays on important part in its
operation.
To achieve results of which you con be justifiably
proud, read these step-by-step instructions carefully.
You'll find that the instructions are divided into
several, main ‘‘sections’’ as well as into steps.
Each easy-to-read section explains a specific part
of the 935 operational procedure.
Save the manual for future reference. Even the most
experienced technicians refer to the operating steps
periodically to quickly ‘‘double check™ thet each
procedure is accomplished properly in correct se-
quence. You will find the manual very helpful in
training new personnel.
NOTE While under certain specific conditions
competitive knives may be sharpened on
the 935, optimum results cannot be assured.
PLEKEGLASS COVER
ALT MATIC OPERATING
TER W я
IMPORTANT
Use only AQ Knives either new or factory re-
conditioned by the American Optical Company.
Knives which have been sharpened previously
by any other methed cannot be satisfactorily
sharpened on the 935
unless they are first
factory reconditioned
by American Optical.
For comments on re-
conditioning knives
to restore proper
facets, eliminate
large nicks, etc., see
page 13.
PLEASE READ OPERATING INSTRUCTIONS, BEGINNING ON PAGE 6
CAREFULLY BEFORE USING YOUR AO 935 SHARPENER.
I. MICROSCOPE EXAMINATION . .
The starting point of any successful sharpening tech-
nique is the careful examination of the condition of
the knife edge using a microscope. Periodic re-ex-
amination during sharpening is equally important.
Please remember! The width of the entire cutting
facet is only from 0.1 to 0.6mm, and nicks in the
edge due to normal use are just a few microns deep.
Therefore, there simply is no satisfactory substitute
for the use of a good microscope in knife inspection.
The microscope should be equipped with a measuring
device such as an eyepiece reticle.
There are two basic methods of illuminating the knife
for examination: When studying the surface of the cut-
ting facet to check for smoothness and uniformity of
. KEY TO SHARPENING SUCCESS
bevel “reflected light” is used as shown in fig-
ure A. The lamp is located above the knife, about
6" to 8” away, and is positioned so that the light is
directed down toward the knife at approximately a
45” angle.
When you wish to study only the edge of the knife to
observe for presence and measurement of nicks,
“transmitted light" is used os shown in figure B.
In both instances above, it is recommended that you
examine the knife at 100X resultant magnification.
Use the wood inspection block provided to hold the
knife at the proper angle under the microscope and
to avoid damage to knife edge. Always wipe the
edge with a clean cloth moistened with solvent such
as xylene before examining.
ll. COARSE HONING OPERATION
The sharpening process begins with coarse honing.
As a general rule, when nicks in the knife edge ex-
ceed 3-4 microns, coarse honing must precede fine
honing. When in doubt, always coarse hone first.
So little metal is removed that you need not be con-
cerned about appreciably reducing the usable “life”
of the knife. In cases where nicks are larger than
10-17 microns, factory reconditioning is required as
discussed on page 13.
Make certain that you begin by using a hone glass
plate with a uniformly even, frosted surface, free of
any “shiny” area. Either use different plate sur-
faces for each length knife to be sharpened or always
begin with longest knives and work down to smallest.
See "Dressing Hone Glass Plates’ page 11.
In coarse honing, the sharpening process begins at
the back of the cutting focet and gradually proceeds
to the front edge of the knife. Bear this "back-to-
"ага
front” honing action in mind when examining the
knife. It is your best guide in recognizing the degree
to which coorse honing has been completed each
time you study the condition of the knife under a
microscope,
The length of time required for correct and complete
coarse honing depends entirely upon the condition
and characteristics of each individual knife. No two
are identical; however, as experience is acquired,
some insight is gained as to ‘timing. Still, as
even the most experienced technicians agree, only
microscopic examination provides proof-positive of
satisfactory coarse honing procedure.
IMPORTANT: The first time a new AO Knife or a
knife just foctory reconditioned by American Optical
is sharpened on the 935, the shorpening process myst
begin with coarse honing. Initial coorse honing of a
new or reconditioned knife will be appreciably longer
thon during subsequent sharpenings. Complete re-
moval of factory edge and nicks may require as long
as 3-4 hours
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|. INSPECT FOR PRESENCE AND SIZE OF NICKS
Clean knife edge with solvent such as xylene. Place the
wood inspection block on the microscope stage first; then
set the knife on the block (a good safety precaution).
Inspect knife edge for presence and size of nicks. Also
note the other surface characteristics of the cutting facet
to more easily recognize the ‘changes’ that will take
place during coarse honing.
2. PUT GLASS HONE PLATE IN UPPER POSITION
Proper positioning of the glass plate is essential for cor-
rect coarse honing. Squeeze plunger to “lift.” Set the
left end of the plate on the upper pad of the plunger unit.
Next insert the right end into the upper “Y” of the plate
support block. Release plunger and slide plate slightly
from front to back to assure proper plate alignment in VW.
3. ATTACH KNIFE WITH AD TRADE MARK TO YOUR
RIGHT (HANDLE SLOT TO LEFT)
Check to see that the knife holder is correctly and se-
curely fastened to shaft (as shown on page 3). With the
two clamps facing ‘up’ and clamp screws loosened, in-
stall knife so that the end with the AD trade mark is to
your right. This places the slotted end of the knife to
your left as you face the front of the 935. Tighten the two
clamp screws until the knife is safely, but temporarily,
fastened. Note: Always sharpen longest knives first.
4. CENTER THE KNIFE USING A RULER
Carefully center the knife for proper balance during honing.
Use a ruler and adjust knife position until you can measure
exactly the same distance from the outside edge of each
clamp to each end of the knife. Keep the knife evenly snug
against the back of the holder. Gradually tighten the two
clamp screws -- alternating from one to the other -= until
the knife is held in place.
5. THOROUGHLY SHAKE COARSE ABRASIVE
Check label on plastic bottle to make certain that you are
using the Coarse Abrasive, No. 937. Use of the correct
abrasive is imperative. Shake very thoroughly (until all
particles are in suspension) to get the proper proportions
of oil and abrasive required for coarse honing. If neces-
sary, remove the dispenser top from bottle and stir to mix
contents.
6. APPLY COARSE ABRASIVE TO PLATE
Squeeze a narrow ribbon’ {about the width of a pencil)
of the coarse abrasive on the glass plate. The “ribbon™
should be approximately equal in length to the knife being
sharpened. Apply coarse abrasive at least an inch inside
the front edge of the plate. Do not permit plate to run dry;
add abrasive if needed. Avoid using excess or abrasive
will “pile up” on plate and may necessitate cleaning of
knife holder.
%
— KNIYES UP TO AND INCLUDING 1
7. FIRST TIMER SETTING IS 60 MINUTES
When beginning coarse honing operation, set the automatic
timer for 60 minutes. This initial setting of an hour holds
true both for knives being sharpened for the first time on
the 935 as well as those previously sharpened on this in-
strument. Close Plexiglass cover and turn on switch. The
knife is automatically stroked against the high-frequency
vibrating glass plate. After the equivalent of three full
strokes on one side, a cam follower automatically turns
knife and hones the other cutting facet, again using three
strokes. Cycle is repeated continuously until time has
run OUT.
85 MM IN LENGTH CAN BE SHARPENED ON THE AO 935

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