Bosch GNF 20 CA Professional Operating Instructions Manual page 12

3 609 929 A85.book Seite 6 Mittwoch, 15. März 2006 11:10 11
Operating Instructions
Wear safety glasses, hearing protection and a
dust protection mask.
Wear protective gloves and sturdy shoes.
The machine may only be used for dry machin-
ing of masonry.
Pre-select the cutting depth, as described in the
same-named section.
Note: To compensate inaccuracies that occur
when breaking away the fin, the cutting depth
must be set approx. 3 mm deeper than the de-
sired slot depth.
Place the machine with the chaser rollers 7 on
the surface to be worked. The cutting unit must
be in the uppermost position.
Switch the machine on.
Press the release button 3 upwards to release
the cutting unit. Slowly lower and plunge the cut-
ting unit into the material.
Always guide the machine with both handles.
The cutting direction is very important.
The machine must always work opposite to the
direction of rotation. Therefore, never move the
machine in the other direction! Otherwise, there
is the danger of it being pushed uncontrolled out
of the cut. Guide the machine in the direction of
the arrow 8.
The machine can either be 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 up-
permost position.
Switch the machine off.
Do not brake coasting cut-off wheels by applying
sideward pressure.
Caution! Diamond cutting discs become very
hot during operation; do not touch them until
they have cooled down.
12 • 3 609 929 A85 • TMS • 13.03.06
Work with moderate
feed, suited to the ma-
terial being worked,
while paying attention
to the cutting direction!
English - 6
Remove the remaining fin of the material with the
break-out tool 21, included in the delivery.
Curved cuts are not possible, as the diamond cut-
ting discs could jam in the material.
When cutting through plate materials, ensure that
the materials are firmly backed on a surface or
supported.
When breaking through walls, e. g. with a rotary
hammer, avoid most of the chipping off of the sur-
face material by first cutting in a slot with maxi-
mum cutting depth.
For cutting especially hard materials, e. g.,
concrete with high gravel content, the diamond
cutting wheel can overheat and become dam-
aged as a result. This is indicated clearly by a
ring of sparks that rotates with the diamond
cutting wheel.
In this case, interrupt the cutting process and al-
low the diamond cutting wheel to cool by letting it
run freely at a no-load speed for a short time.
A noticeable drop in work performance and a ro-
tating spark ring indicate that the diamond cutting
wheel has become dull. It can be resharpened
with brief cuts in an abrasive material (e. g.,
chalky sandstone).
Rip Fence (Accessory, GNF 20 CA)
14
To cut additional parallel slots, press the guide
bolt 15 of the rip fence 14 down into the already
cut slot and carry out the cutting procedure.
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