Bosch GSB 20-2 Instrucciones De Servicio página 12

Electronic Torque Limitation/
Speed Preselection
(Power Control – GSB 20-2 RET)
The effective torque at the drilling spindle can be
set variably with the dial control 5.
1 = low torque
10 = high torque
The maximum speed is automatically adapted to
the adjusted torque.
If the pre-selected torque is reached during
screwdriving, the machine switches off and
stops. If the load on the machine is then removed
with the On/Off switch 7 still pressed, the contin-
ued run is at very low speed for safety reasons.
After briefly releasing the On/Off switch 7, the
previous operating mode is automatically re-
turned to, so that the next screw is tightened with
the same torque.
Replacing the Drill Chuck
Key chuck (see figure
To unscrew key chuck 16, position open-end
spanner (SW 17) on key face.
Place the chuck key in one of the 3 bores and
loosen the chuck by turning it to the left using the
key as a lever. If the key chuck is frozen in place,
a tap on the chuck key should loosen it.
Keyless Chuck (see figure
Insert hexagonal tool (Allen key or screwdriver
bit) into the chuck and clamp the free end in a
vice. Position open-end spanner on key face of
drill spindle and loosen chuck in an anti-clock-
wise direction, as if loosening a screw.
The drill chuck is mounted in reverse order.
The chuck must be tightened with a
torque of approx. 30 – 35 Nm.
12 • 2 609 932 127 • 02.10
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A
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B
English - 4
Tips
Speed as well as torque setting depend on the
material and can be determined by practical test-
ing. Always start with the lowest setting.
After longer periods of working at low speed, al-
low the machine to cool down by running for ap-
prox. 3 minutes at maximum speed with no load.
For drilling in tiles, set the selector switch 4 to the
symbol "Drilling and Screwdriving". Do not switch
over to the symbol "Impact Drilling" or work with
impact until after drilling through the tile.
Carbide tipped drill bits are required for jobs
when working in concrete, masonry and brick
wall.
Sharpening Drill Bits
For drilling in metal, use only perfectly sharpened
HSS drills. The appropriate quality is guaranteed
by the Bosch accessories program.
Twist drills from 3.5 – 10 mm can easily be sharp-
ened with the drill sharpener (see accessories).
Bench Stand
We recommend the use of a bench stand (see
accessories) for work where greater precision is
particularly required.
Machine Vice
The machine vice can be obtained as an acces-
sory and clamps work pieces tightly for drilling.
This prevents the work piece from turning and
any accidents this would cause.