Bosch GSB 90-2 E Professional Manual Original página 13

Starting Operation
Observe 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 con-
nected to 220 V.
Switching On and Off
To start the machine, press the On/Off switch 4
and keep it depressed.
The machine runs with variable
speed between 0 and maximum,
depending on the pressure applied
to the On/Off switch 4. Light pres-
sure on the On/Off switch 4 results
in low rotational speed, thus allow-
ing smooth, controlled starts. Further pressure on
the switch results in an increase in speed. Do not
strain the machine so heavily that it comes to a
standstill.
Lock the pushed On/Off
3
switch 4 by pushing the lock-
on button 3 upward.
4
To switch off the machine, release the On/Off
switch 4 or when locked with the lock-on but-
ton 3, press the On/Off switch 4 briefly and then
release.
Gear Selection, Mechanical
Two speed ranges can be preselected with the
gear selector 7:
1st gear:
Low speed range; for working with
large drilling diameter.
2nd gear:
Higher speed range; for working
with small drilling diameter.
Actuate the gear selector 7 only when the ma-
chine is at a standstill!
If the gear selector 7 cannot be fully engaged at
standstill, lightly rotate the drive/drill spindle with
the drill bit by twisting the chuck.
1 609 929 M05 • 9.7.07
Drilling and Impact Drilling
Drilling
Push selector switch 2 to the right.
Impact Drilling
Push selector switch 2 to the left.
Actuate the selector switch only at standstill
or just before the machine comes to a stop.
If the selector switch 2 does not fully engage at
standstill, lightly rotate the drive spindle with the
drill bit by twisting the chuck.
Safety Clutch
If the tool insert becomes caught or jammed, the
drive to the drill spindle is interrupted. Because of
the forces that occur, always hold the power
tool firmly with both hands and provide for a
secure stance.
Replacing the Drill Chuck
Loosening the Drill Chuck
(see figure )
D
To unscrew the key type drill chuck 1, position
the open-end spanner (size 17 mm) against the
spanner flats.
Insert the chuck key into one of the holes and use
it as a lever to release the drill chuck by turning in
anticlockwise direction, as if loosening a screw.
Loosen a tightly sitting drill chuck with a light blow
on the chuck key.
Tightening the Drill Chuck
The drill chuck is mounted in reverse order.
Operating Instructions
For drilling in tiles, set the selector switch 2 to the
"Drilling" symbol. Do not switch over to the "Im-
pact Drilling" symbol until after drilling through the
tile, then work with impact.
Carbide tipped drill bits are required for jobs
when working in concrete, masonry and brick
wall.
Optimal drilling progress is achieved when using
carbide tipped drill bits with hexagon clamping
shank (accessories).
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