Dust/Chip Extraction; Switching On/Off - Bosch 3-28 DRE GBH Professional Manual Del Usuario

18 | English
In this case, turn the front sleeve (20) in the opposite direc-
tion to the arrow by one full turn. This will allow the tool
holder to be fully tightened.
– Turn the impact/mode selector switch (9) to the "drilling"
position.
Removing the application tool (see figure H)
– Hold the retaining ring (21) of the keyless quick-change
chuck firmly in place. Open the tool holder by turning the
front sleeve (20) in the direction of the arrow until the
tool can be removed.

Dust/Chip Extraction

The dust from materials such as lead paint, some types of
wood, minerals and metal can be harmful to human health.
Touching or breathing in this dust can trigger allergic reac-
tions and/or cause respiratory illnesses in the user or in
people in the near vicinity.
Certain dusts, such as oak or beech dust, are classified as
carcinogenic, especially in conjunction with wood treatment
additives (chromate, wood preservative). Materials contain-
ing asbestos may only be machined by specialists.
– Use a dust extraction system that is suitable for the ma-
terial wherever possible.
– Provide good ventilation at the workplace.
– It is advisable to wear a P2 filter class breathing mask.
The regulations on the material being machined that apply in
the country of use must be observed.
Avoid dust accumulation at the workplace. Dust can
u
easily ignite.
Dust extraction with GDE 16 Plus (accessory)
(see figure I)
For dust extraction, the GDE 16 Plus (accessory) is re-
quired.
The dust extractor must be suitable for the material being
worked on.
When extracting dry dust or dust that is especially detri-
mental to health or carcinogenic, use a special dust ex-
tractor.
Operation
Products that are only sold in AUS and NZ: Use a resid-
u
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
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 (9).
1 609 92A 6GJ | (16.12.2021)
– To change the operating mode, press the release
button (8) and turn the impact/mode selector switch (9)
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 screwdriv-
ing
Vario-Lock position for adjusting the chisel po-
sition
The impact/mode selector switch (9) will not
engage in this position.
Position for chiselling
Setting the Rotational Direction
The rotational direction switch (13) is used to change the ro-
tational direction of the power tool. However, this is not pos-
sible while the on/off switch (7) is being pressed.
Only operate the rotational direction switch (13)
u
when the power tool is not in use.
Always set the rotational direction to clockwise rotation for
hammer drilling, drilling and chiselling.
– Clockwise rotation: Push the rotational direction
switch (13) all the way to the right.
– Anticlockwise rotation: Push the rotational direction
switch (13) all the way to the left.

Switching On/Off

– To switch on the power tool, press the on/off switch (7).
– To switch off, release the on/off switch (7).
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 (7) to varying ex-
tents.
Applying light pressure to the on/off switch (7) 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 36 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 (9) to the "Vario-
Lock" position.
– Turn the application tool to the required chisel position.
– Turn the impact/mode selector switch (9) to the "chis-
elling" position. With this, the tool holder is locked.
– Set the rotational direction for chiselling to clockwise.
Bosch Power Tools