Bosch GNF 20 CA Operating instructions

EURO • Printed in Germany • BA 3 609 929 804 • GNF 20/35 CA • Titel (Vorderseite) • OSW 05/01
GNF 20/35 Titel Euro Vorders. Seite 1 Dienstag, 15. Mai 2001 12:33 12
Operating Instructions
Instructions d’emploi
Instrucciones de servicio
Manual de instruções
Istruzioni d’uso
Oδηγία χειρισµού
Kullanım kılavuzu
GNF 20: 3 607 000 060
GNF 20: 3 600 390 023
GNF 35: 3 609 202 039
GNF 20: 3 603 345 005
GNF 35: 3 609 202 040
GNF 20:
4 mm (5x) 3 609 202 041
GNF 35:
4 mm (3x) 3 609 202 041
6 mm (4x) 3 609 202 042
GNF 20: 1 607 950 043
GNF 35: 3 607 950 017
GNF 20: 3 605 438 025
GNF 35: 3 605 438 053
3 607 959 005
GNF ...
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Ø 29 mm: 3 607 000 057
Ø 35 mm: 1 609 202 230
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5 • 3 609 929 804 • 05.01
Tool Specifications
Wall chasing machine
Part number
Rated power
Output power
No-load speed
Diamond cutting discs Ø
Mounting hole
Slot depth
Slot width
Weight (without optional extras) approx.
Safety class
0 601 612 5..
900 W
520 W
9 300 rpm
max. 115 mm
22.2 mm
0 – 20 mm
7 – 23 mm
2.8 kg
/ II
Machine Elements
0 601 621 7..
1 400 W
750 W
9 300 rpm
max. 150 mm
22.2 mm
0 – 35 mm
7 – 39 mm
4.1 kg
/ II
For Your Safety
Release lock
Release button for the cutting unit
Cutting depth scale
Release button for the depth stop
Depth stop
Chaser rollers
Spindle lock
On/Off switch
Service indicator (GNF 35 CA)
Vacuum hose*
Vacuuming connection piece
Parallel guide* (GNF 20 CA)
Guide bolt (GNF 20 CA)
Grinder spindle
Mounting flange
Diamond cutting disc*
Clamping nut
Two-pin spanner for clamping nut
Break-out tool
Working safely with this machine is possible only when the
operating and safety information
are read completely and the instructions contained therein are
strictly followed. In addition, the
general safety instructions in the
enclosed booklet must be followed. Before using for the first
time, ask for a practical demonstration.
If the mains cable is damaged or
cut through while working, do not
touch the cable but immediately
pull the mains plug. Never use the
machine with a damaged cable.
Wear protective goggles, ear protection and a dust protection mask.
Wear protective gloves and sturdy
When necessary, also wear an
* Optional accessories
* Not all of the accessories illustrated or described are
included as standard delivery.
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■ When working with the machine, always hold it
firmly with both hands and provide for a secure
■ Always direct the cable to the rear away from
the machine.
■ Connect machines that are used in the open
via a residual current device (RCD) with an actuating current of 30 mA maximum. Use only
extension cables that are approved for outdoor
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■ Insert the mains plug only when the machine is
switched off.
■ Do not clamp the machine in a vice.
■ Always switch off the machine and allow to
come to a stop before placing it down.
■ Do not work with materials containing asbestos.
■ Only use diamond cutting discs with a maximum permissible speed that is at least as high
as the no-load speed of the machine.
■ Check the diamond cutting discs before use.
The diamond cutting discs must be mounted in
exact alignment and be able to rotate freely.
Carry out a test run for at least 30 seconds
without any load. Do not use any diamond cutting discs that are damaged, out-of-balance, or
■ Observe the dimensions of the diamond cutting discs. The hole diameter must fit the
mounting flange 15. Do not use any reduction
parts or adapters.
■ Protect diamond cutting discs against impact,
shock and grease.
■ Apply the machine to the workpiece only when
switched on.
■ Keep hands away from the rotating diamond
cutting disc.
■ Pay attention to the direction of rotation. Always hold the machine so that sparks and
grinding dust fly away from the body.
■ Be careful when cutting grooves, e. g. in loadcarrying walls: See information on structures.
■ Do not drill, fasten or cut into blind areas
where electric, gas or water lines may exist.
Use appropriate detectors to determine if
these lines are hidden in the work area or
call the local utility company for assistance.
Contacting electric lines may cause fire or
electric shock. Striking a gas line will probably
result in explosion. Breaking into a water pipe
will cause property damage or may cause an
electric shock.
■ Caution! Sparks can also reach combustible
materials that are covered.
■ Blocking the cutting disc leads to jerking reaction forces on the machine. In this case switch
off the machine immediately.
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■ Observe the manufacturer’s instructions for
mounting and operating the diamond cutting
■ Caution! Diamond cutting discs do not stop
running immediately when the machine is
turned off. Do not exert any pressure against
the side of the diamond cutting discs.
■ The machine must be operated only with dust
extraction. In addition, wear a dust mask. The
vacuum cleaner must be approved for the extraction of masonry dust.
■ Caution! Diamond cutting discs become very
hot during operation; do not touch them before
they have cooled down.
■ Never allow children to use the machine.
■ Bosch is only able to ensure perfect functioning of the machine if the original accessories
intended for it are used.
Information Structures
Slots in load carrying walls are subject to the
Standard DIN 1053, Part 1 or country-specific
These regulations are to be observed under all
circumstances. Before beginning work, consult
the responsible structural engineer, architects or
the construction supervisor.
The permitted slot depth and width depends on
the slot length, wall thickness and the used building material.
Intended Use
With a firm support of the cutting guide, the machine is intended to cut or slot mainly mineral materials such as reinforced concrete, brickwork
and road surfaces without the use of water.
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Changing the Tool
■ Before any work on the machine itself, pull
the mains plug.
■ Wear protective gloves.
■ Use only diamond cutting discs suitable for
dry cutting of the material with an allowable
speed matching at least the no-load speed
of the machine.
Swiveling out the cutting unit
For tool change, the cutting unit must be swiveled
out completely.
Place the machine on a firm surface. Turn the release lock 1 to the left, using e. g. the spanner
end of the two-pin spanner 19.
This releases the cutting unit and immediately swivels it upwards by means of
Removing the clamping assembly
With the spindle locking button 7, lock the grinder
spindle (only when the grinder spindle is at a
Loosen the clamping nut 18 using the two-pin
spanner 19 and unscrew it. Remove the spacer
discs 17 and the mounting flange and clean the
clamping parts.
Determining the slot width
The slot width results from the amount of spacer
discs between the two diamond cutting discs 16
and the cutting width of the diamond cutting
The slot width is calculated as follows:
Slot width = Thickness of the spacer discs + width
of the diamond cutting discs (4 mm).
The allowable slot width is shown in the section
“Tool Specifications”.
The machine may only be operated with one or
two diamond cutting discs.
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Mounting the clamping assembly
Place the mounting flange 15 onto the tool spindle 14. The mounting flange 15 with its driving
feature must be properly seated on the tool spindle.
Place the diamond cutting disc 16 and the spacer
discs 17 on the mounting flange 15.
Regardless of the required slot width, all spacer
discs 17 included in the delivery must be
At least one spacer disc 17 must be mounted between two diamond cutting discs 16.
When assembling the diamond cutting discs, ensure that the direction-of-rotation arrows on the
diamond cutting discs match with the direction-of-rotation arrow on the housing.
Screw on the clamping nut 18 and tighten with
the two-pin spanner 19.
Swivel the cutting unit back again. Check the
locking system of the cutting unit.
When working with 2 diamond cutting discs
always replace them in pairs.
Cutting Depth Pre-Selection
Press the release button 4 at the depth stop 5
and push the depth stop to the required cutting
depth. The cutting depth scale 3 can be used as
a reference for this.
Let go of the release button 4 again.
Ensure that the depth stop 5 is engaged.
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Dust Extraction
Initial Operation
The machine must be operated
only with dust extraction. The
vacuum cleaner must be approved for the extraction of masonry dust.
In case of a malfunction of the
dust extraction system, stop
working, switch the machine off
and correct the malfunction of
the dust extraction system.
The machine can be plugged directly into the receptacle of a Bosch general-purpose vac with remote starting control. The vac starts automatically when the machine is switched on.
The vacuum cleaner must be suitable for the material to be worked.
When vacuuming dry dust that is especially detrimental to health or carcinogenic, use a special
vacuum cleaner.
Bosch offers suitable vacuum cleaners for all materials to be worked.
For dust extraction using an external vacuum
cleaner, a suction adapter must be used in this
case (see accessories). Insert the suction
adapter and suction hose fixture firmly.
Check for correct mains voltage: The voltage
of the power source must agree with the voltage
specified on the nameplate of the machine.
Equipment marked with 230 V can also be connected to 220 V.
The cutting unit must have engaged in
the uppermost position before the machine is switched on, so that the diamond cutting discs do not touch the
Switching on and off
Switching on: Slide the On/Off switch 8
forward and press down to the
front until it latches.
Switching off: Press down the On/Off switch 8
to the rear - the switch springs to
the off position.
Check the diamond cutting discs before
use. The diamond cutting discs must be
mounted in exact alignment and be able to
rotate freely. Carry out a test run for at least
30 seconds without any load. Do not use
any diamond cutting discs that are damaged, out-of-balance, or vibrate.
Starting Current Limiting
As a result of soft starting, a 13-A fuse is adequate.
Constant Electronics
The constant speed electronics hold the speed at
no-load and when under load nearly constant and
ensure uniform working performance.
Overload Protection
When overloaded, the motor comes to a stop.
Relieve the load on the machine immediately and
allow to cool for approx. 30 seconds at the highest no-load speed.
Restarting Protection (GNF 35 CA)
Prevents uncontrolled restarting of the machine
after an interruption in the mains supply.
The mains supply remains interrupted and the
service indicator 9 lights up.
Restarting operation: Switch the On/Off
switch 8 to the Off position and start the machine
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Operating Instructions
Wear protective goggles, ear
protection and a dust protection
Wear protective gloves and
sturdy shoes.
■ The machine may only be used for dry machining of masonry.
Pre-select the cutting depth, as described in the
same-named section.
Note: To compensate inaccuracies that occur
when breaking away the fins, the cutting depth
must be set approx. 3 mm deeper than the required slot depth.
Place the machine with the chaser rollers 6 on
the surface to be worked. The cutting unit must
be in the uppermost position.
Switch the machine on.
Press the release button 2 upwards to release
the cutting unit. Slowly lower and plunge the cutting unit into the material.
Always guide the machine with both handles.
Work with moderate
feed, suited to the material being worked,
while paying attention
➊ to the cutting direction!
Important is the direction in which cutting is performed.
The machine must always work opposite to the
direction of rotation. Therefore, never move the
machine in the other direction! Otherwise, the
danger exists of it being pushed uncontrolled
out of the cut.
The machine can be both pushed or pulled in the
cutting direction. Vertical slots can easily be cut
by pulling the machine from top to bottom.
After finishing the working procedure, swivel the
cutting unit out of the slot with the machine still
running, until the cutting unit engages in the uppermost position.
Switch the machine off.
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Do not brake coasting cutting disks with side
■ Caution! Diamond cutting discs become
very hot during operation; do not touch
them before they have cooled down.
Remove the remaining fin of the material with the
break-out tool 20, included in the delivery.
Curved cuts are not possible, as the diamond cutting discs could jam in the material.
When cutting through plate materials, ensure that
the materials are firmly backed on a surface or
When breaking through walls, e. g. with a rotary
hammer, the chipping off of the surface material
can be widely avoided when a slot with maximum
cutting depth is cut in first.
For cutting especially hard material, e. g.,
concrete with high gravel content, the diamond cutting disc can overheat and become damaged as a result. This is indicated clearly by a ring of sparks that rotates
with the diamond cutting disc.
In this case, interrupt the cutting process and allow the diamond cutting disc to cool by running
frely at no-load speed for a short time.
Noticeable decreasing work progress and a rotating spark ring are indications of a diamond cutting
disc that has become dull. With brief cuts in an
abrasive material (e. g., chalky sand stone), it
can be sharpened again.
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Parallel Guide
(Optional extra, GNF 20 CA)
Service Indicator 9 (GNF 35 CA)
When the carbon brushes are worn out, the machine switches itself off. This is indicated approx.
eight hours beforehand by the lighting or blinking
of the service indicator 9. The machine must then
be sent to customer service for maintenance (for
addresses, see Section “Service and Customer
To cut additional parallel slots, press the guide
bolt 13 of the parallel guide 12 down into the already cut slot and carry out the cutting procedure.
Maintenance and Cleaning
■ Before any work on the machine itself, pull
the mains plug.
For safe and proper working, always keep
the machine and the ventilation slots clean.
After finishing work, disassemble the diamond
cutting discs and clean the clamping parts and
the protective cover.
If the machine should fail despite the care taken
in manufacturing and testing procedures, repair
should be carried out by an authorized after-sales
service centre for Bosch power tools.
In all correspondence and spare parts orders,
please always include the 10-digit order number
given on the nameplate of the machine.
WARNING! Important instructions for connecting a new 3-pin plug to the 2 wire cable.
The wires in the cable are coloured according to
the following code:
We guarantee Bosch appliances in accordance
with statutory/country-specific regulations (proof
of purchase by invoice or delivery note).
Damage attributable to normal wear and tear,
overload or improper handling will be excluded
from the guarantee.
In case of complaint please send the machine,
undismantled, to your dealer or the Bosch Service Centre for electric power tools.
Noise/Vibration Information
Measured values determined according to
EN 50 144 (lime-sand brick).
Typically the A-weighted noise levels of the product are: sound pressure level: 97 dB (A); sound
power level: 110 dB (A).
Wear ear protection!
The typical weighted acceleration is 4 m/s2.
strain relief
live = brown
neutral = blue
To be fitted
by qualified
professional only
Do not connect the blue or brown wire to the
earth terminal of the plug.
Important: If for any reason the moulded plug is
removed from the cable of this machine it must be
disposed of safely.
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