Bosch Professional GBH 2-28 Series Original Instructions Manual page 11

Start-up
Pay attention to the mains voltage. The voltage of the
u
power source must match the voltage specified on the
rating plate of the power tool. Power tools marked
with 230 V can also be operated with 220 V.
Setting the Operating Mode
The operating mode of the power tool is selected using the
impact/mode selector switch (11).
– To change the operating mode, press the release but-
ton (10) and turn the impact/mode selector switch (11)
until it clicks into the required position.
Note: Only change the operating mode when the power tool
is switched off. Otherwise, the power tool may become dam-
aged.
Position for hammer drilling into concrete
or stone
Position for drilling without impact in wood,
metal, ceramic and plastic and for screw-
driving
Vario-Lock position for adjusting the chisel
position
The impact/mode selector switch (11) will
not engage in this position.
Position for chiselling
Setting the Rotational Direction
The rotational direction switch (7) is used to change the ro-
tational direction of the power tool. However, this is not pos-
sible while the on/off switch (9) is being pressed.
Only operate the rotational direction switch (7) when
u
the power tool is not in use.
Always set the rotational direction to clockwise rotation for
hammer drilling, drilling and chiselling.
– Rotate clockwise: Turn the rotational direction
switch (7) on both sides until it stops in the
– Rotate anticlockwise: Turn the rotational direction
switch (7) on both sides until it stops in the
Switching On/Off
– To switch on the power tool, press the on/off switch (9).
– To lock the on/off switch (9), press and hold it while also
pushing the lock-on button (8).
– To switch off the power tool, release the on/off switch
(9). If the on/off switch (9) is locked, press the switch
first and then release it.
Bosch Power Tools
Adjusting the Speed/Impact Rate
– Adjust the speed/impact rate of the power tool when it is
on by pressing in the on/off switch (9) to varying extents.
Applying light pressure to the on/off switch (9) results in a
low rotational speed/impact rate. Applying increasing pres-
sure to the switch increases the speed/impact rate.
Practical Advice
Only apply the power tool to the screw/nut when the
u
tool is switched off. Rotating tool inserts can slip off.
Changing the chiselling position (Vario-Lock)
You can lock the chisel in 40 different positions, so you can
select the optimum working position for each task.
– Insert the chisel into the tool holder.
– Turn the impact/mode selector switch (11) to the "Vario-
Lock" position.
– Turn the application tool to the required chisel position.
– Turn the impact/mode selector switch (11) to the "chis-
elling" position. With this, the tool holder is locked.
– Set the rotational direction for chiselling to clockwise.
Chiselling with lock function
To chisel for extended periods without pressing the on/off
switch (9), lock the on/off switch in "chiselling" operating
mode.
– To lock the power tool, press the on/off switch (9) down
fully whilst simultaneously pressing the lock-on
switch (8).
– To switch the lock off, press the lock-on button (8) again.
Note: If you switch to a different operating mode while the
on/off switch is locked, the power tool will switch off.
Vibration damping
The integrated vibration damping function re-
duces the generated vibration.
Do not continue to use the power tool if the damping
u
element is damaged.
Inserting screwdriver bits (see figure K)
Only apply the power tool to the screw/nut when the
u
tool is switched off. Rotating tool inserts can slip off.
A universal holder (26) with SDS-plus shank (accessory) is
required to work with screwdriver bits.
position.
– Clean and lightly grease the insertion end of the shank.
– Insert the universal holder into the tool holder while turn-
position.
ing it until it locks automatically.
– Check that it is locked by pulling the universal holder.
– Insert a screwdriver bit in the universal holder. Only use
screwdriver bits that fit the screw head.
– To remove the universal holder, slide the locking sleeve
(5) backwards and remove the universal holder (26)
from the tool holder.
English | 11
1 609 92A 5N7 | (16.03.2020)