Position for drilling without impact
in wood, metal, ceramic and plastic
Position for hammer drilling in
concrete or stone
When the drilling tool does not im-
mediately rotate upon switching
on, allow the machine to run slowly
until the drilling tool rotates.
Vario-Lock position for adjustment
of the chiselling position
Position for chiselling
Switching On and Off
To start the machine, press the On/Off switch 4
and keep it depressed.
To switch off the machine, release the On/Off
switch 4.
For low temperatures, the power tool reaches
the full hammer/impact capacity only after a cer-
tain time.
Setting the Speed/Impact Rate
The speed/impact rate of the switched on pow-
er tool can be variably adjusted, depending on
how far the On/Off switch 4 is pressed.
Light pressure on the On/Off switch 4 results in
low speed/impact rate. Further pressure on the
switch increases the speed/impact rate.
Preselecting the Speed/Impact Frequency
(GBH 4 DSC)
The electronic control enables stepless speed
and impact preselection in accordance with the
material to be worked.
The constant electronic control keeps the prese-
lected speed and impact rate nearly constant
between no-load and load conditions.
Bosch Power Tools
All manuals and user guides at all-guides.com
The maximum hammering capacity is achieved
when the thumbwheel 5 is set to position "6".
For lower speed settings, the hammering capac-
ity is lower due to technical reasons.
Select the speed with the thumbwheel 5 accord-
ing to the material.
The data in the following table are recommend-
ed values.
Application
Mode Selector
Switch
Hammer Drilling
Chiselling
Drilling
Needle-descaling
Overload Clutch
If the tool insert becomes caught or
jammed, the drive to the drill spindle is in-
terrupted. 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 switch-
ing the machine on with the drilling tool
jammed, high reaction torques can occur.
Changing the Chiselling Position (Vario-Lock)
The chisel can be locked in 36 positions. In this
manner, the optimum working position can be
set for each application.
Insert the chisel into the tool holder.
Press and hold the unlocking button 8 and turn
the mode selector switch 7 to "Changing the
chiselling position (Vario-lock)".
English | 21
Thumb-
wheel 5
5 – 6
3 – 6
1 – 6
3 – 6
1 619 929 748 | (25.7.07)