Switching On/Off; Practical Advice - Bosch GBH 4-32 DFR Professional Manual Original

16 | English
reactions and/or lead to respiratory infections of the user or
bystanders.
Certain dust, such as oak or beech dust, is considered carci-
nogenic, especially in connection with wood-treatment ad-
ditives (chromate, wood preservative). Materials containing
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 ma-
terials to be worked.
Avoid dust accumulation at the workplace. Dust can
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easily ignite.
Operation
Products that are only sold in AUS and NZ: Use a resid-
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ual current device (RCD) with a nominal residual current
of 30 mA or less.
Start-up
Pay attention to the mains voltage. The voltage of the
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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 (7).
– To change the operating mode, turn the impact/mode se-
lector switch (7) to 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 drilling without impact in wood,
metal, ceramic and plastic and for screw-
driving
Position for hammer drilling into concrete
or stone
Vario-Lock position for adjusting the chisel
position
The impact/mode selector switch (7) will
not engage in this position.
Position for chiselling
Setting the Rotational Direction
The rotational direction switch (10) is used to change the ro-
tational direction of the power tool.
Always set the rotational direction to clockwise rotation for
hammer drilling, drilling and chiselling.
1 609 92A 8AA | (20.09.2022)
– Rotate clockwise: Turn the rotational direction
switch (10) until it stops in the
– Rotate anticlockwise: Turn the rotational direction
switch (10) until it stops in the

Switching On/Off

– To start the power tool, press the on/off switch (9) and
keep it pressed.
– To switch off, release the on/off switch (9).
For low temperatures, the power tool reaches the full ham-
mer/impact capacity only after a certain time.
Adjusting the Speed/Impact Rate
You can adjust the speed/impact rate of the power tool when
it is on by pressing in the on/off switch (9) to varying ex-
tents.
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.
Changing the chiselling position (Vario-Lock)
You can lock the chisel in 12 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 (7) to the "Vario-
Lock" position.
– Turn the application tool to the required chisel position.
– Turn the impact/mode selector switch (7) to the "chis-
elling" position. With this, the tool holder is locked.
– Set the rotational direction for chiselling to clockwise.

Practical Advice

Only apply the power tool to the screw/nut when the
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tool is switched off. Rotating tool inserts can slip off.
Setting the drilling depth (see figure E)
You can use the depth stop (13) to set the required drilling
depth X.
– Press the button for depth stop adjustment (11) and in-
sert the depth stop into the auxiliary handle (12).
The fluting on the depth stop (13) must face downwards.
– Insert the SDS-plus application tool into the SDS-plus tool
holder (3) to the stop. Otherwise, the movability of the
SDS-plus drilling tool can lead to incorrect adjustment of
the drilling depth.
– Pull the depth stop far enough out that the distance
between the drill bit tip and the edge of the depth stop
corresponds to the required drilling depth X.
Overload clutch
If the application tool jams or snags, the power trans-
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mission to the drill spindle will be interrupted. Always
hold the power tool firmly with both hands to with-
stand the forces this may create and adopt a position
with stable footing.
Switch the power tool off immediately and remove the
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application tool if the power tool becomes blocked.
position.
position.
Bosch Power Tools