Working Advice - Bosch GSB Professional 21-2 Notice Originale

OBJ_DOKU-26857-001.fm Page 17 Thursday, May 26, 2011 3:57 PM
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.
Safety Clutch
To limit high reaction torque, the pow-
er tool is equipped with a safety 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 loos-
en the tool insert. When switching the machine on with
the drilling tool jammed, high reaction torques can oc-
cur.
Adjusting the Speed/Impact Frequency
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.
Preselecting the Speed/Impact Frequency
With the thumbwheel for speed preselection 8, the required
speed/impact frequency can be preselected even during op-
eration.
The required speed/impact frequency depends on the mate-
rial and the working conditions, and can be determined
through practical testing.
Electronic Speed Preselection (GSB 21-2 RCT)
With the thumbwheel for electronic speed preselection 3, the
required speed/impact frequency can be selected even if the
machine is running.
The required speed/impact frequency depends on the mate-
rial and the working conditions, and can be determined
through practical testing.
Bosch Power Tools
Constant Electronic Control (GSB 21-2 RCT)
The constant electronic control keeps the preselected speed
and impact rate nearly constant between no-load and load
conditions.
Electronic Torque Limitation/Speed Preselection
(Torque Control) (GSB 21-2 RCT)
Drilling with speed preselection: Set the se-
lector switch 4 to the "Drilling" symbol. The re-
quired speed can be selected with the thum-
bwheel 3; it can also be adjusted during
operation.
Screwdriving with torque limitation: Set the
selector switch 4 to the "Screwdriving" sym-
bol. The effective torque at the drill spindle can
be variable adjusted with the thumbwheel 3
during operation:
I=low torque, III=high torque.
The maximum speed is automatically adapted to the adjusted
torque.
If the preselected torque is reached during screwdriving, the
machine switches off; the drilling tool no longer rotates. If the
load on the machine is then removed with the On/Off switch 7
still pressed, the drilling tool continues to run only at very low
speed for safety reasons.
After briefly releasing the On/Off switch 7, the next screw can
be driven in with the same torque.
For screwdriving without torque limitation,
turn the thumbwheel 3 to the right stop. This
setting is required, when the torque in
position III is not sufficient.

Working Advice

Apply the power tool to the screw/nut only when it is
switched off. Rotating tool inserts can slip off.
Tips
After longer periods of working at low speed, allow the ma-
chine to cool down by running it for approx. 3 minutes at max-
imum speed with no load.
For drilling in tiles, set the selector switch 2 to the "Drilling"
symbol. Do not switch over to the symbol "Impact Drilling" or
work with impact until after drilling through the tile.
Use carbide tipped drill bits when working in concrete, ma-
sonry and brick wall.
For drilling in metal, use only perfectly sharpened HSS drill
bits (HSS=high-speed steel). The appropriate quality is guar-
anteed by the Bosch accessories program.
Twist drills from 2.5–10 mm can easily be sharpened with
the drill bit sharpener (see accessories).
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2 609 932 659 | (26.5.11)