Bosch Professional GSB 21-2 Original Instructions Manual page 9

OBJ_BUCH-945-002.book Page 9 Friday, October 21, 2016 12:48 PM
Clamp the short end of a hex key 18 into the keyless chuck 1.
Place the machine on a stable surface (e. g. a workbench).
Hold the machine firmly and loosen the keyless chuck 1 by
turning the hex key 18 in rotation direction . Loosen a tight-
seated keyless chuck by giving the long end of the hex key 18
a light blow. Remove the hex key from the keyless chuck and
completely unscrew the keyless chuck.
Mounting the Drill Chuck (see figure I)
The keyless chuck/key type drill chuck is mounted in reverse
order.
 Remove the steel pin from the drill hole on the spindle
neck after mounting is completed.
The drill chuck must be tightened with a tightening
torque of approx. 67–74 Nm.
Dust/Chip Extraction
 Dust from materials such as lead-containing coatings,
some wood types, minerals and metal can be harmful to
one's health. Touching or breathing-in the dust can cause
allergic reactions and/or lead to respiratory infections of
the user or bystanders.
Certain dust, such as oak or beech dust, is considered car-
cinogenic, especially in connection with wood-treatment
additives (chromate, wood preservative). Materials con-
taining asbestos may only be worked by specialists.
– Provide for good ventilation of the working place.
– It is recommended to wear a P2 filter-class respirator.
Observe the relevant regulations in your country for the
materials to be worked.
 Prevent dust accumulation at the workplace. Dust can
easily ignite.
Operation
Starting Operation
 Observe correct mains voltage! The voltage of the
power source must agree with the voltage specified on
the nameplate of the machine. Power tools marked
with 230 V can also be operated with 220 V.
Reversing the rotational direction (see figures J – K)
 Actuate the rotational direction switch 5 only when the
machine is at a standstill.
The rotational direction switch 5 is used to reverse the rota-
tional direction of the machine. However, this is not possible
with the On/Off switch 7 actuated.
Right rotation: For drilling and driving in screws, push the ro-
tational direction switch 5 downward on the left side and at
the same time upward on the right side.
Left rotation: For loosening and unscrewing screws and
nuts, push the rotational direction switch 5 upward on the left
side and at the same time downward on the right side.
Bosch Power Tools
Setting the operating mode
Drilling and Screwdriving
Set the selector switch 2 to the "Drilling" symbol.
Impact Drilling
Set the selector switch 2 to the "Impact drilling"
symbol.
The selector switch 2 engages noticeably and can also be
actuated with the machine running.
Gear selection, mechanical
 The gear selector 9 can be actuated on machines run-
ning at low speed. However, this should not be done
when the machine is stopped, at full load or running at
maximum speed.
Two speed ranges can be preselected with the gear selector 9.
Gear I:
Low speed range; for working with large drill-
ing diameter or for driving in screws.
Gear II:
High speed range; for working with small
drilling diameter.
If the gear selector 9 cannot be fully engaged, lightly rotate
the drive spindle with the drill bit by twisting the drill chuck.
Switching On and Off
To start the machine, press the On/Off switch 7 and keep it
pressed.
To lock the pressed On/Off switch 7, press the lock-on
button 6.
To switch off the machine, release the On/Off switch 7 or
when it is locked with the lock-on button 6, briefly press the
On/Off switch 7 and then release it.
Overload Clutch
To limit high reaction torque, the
power tool is equipped with an over-
load clutch (Anti-Rotation).
 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.
 If the power tool jams, switch the machine off and loosen
the tool insert. When switching the machine on with the
drilling tool jammed, high reaction torques can occur.
Adjusting the Speed/Impact Rate
The speed/impact rate of the switched on power tool can be
variably adjusted, depending on how far the On/Off switch 7
is pressed.
Light pressure on the On/Off switch 7 results in low speed/im-
pact rate. Further pressure on the switch increases the speed/
impact rate.
English | 9
1 609 92A 374 | (21.10.16)