Bosch GBH 3-28 DFR (061124A000) - Инструкция по эксплуатации - Страница 18

18

 | English 

1 619 92A 06A | (2.10.13)

Bosch Power Tools

– Position the the guide pipe 

27

 of the dust extraction at-

tachment in its holding fixture in such a manner that the 
head of the dust extraction attachment faces against the 
surface to be drilled. Do not slide the guide pipe 

27

 further 

over the telescopic pipe 

25

 of the dust extraction attach-

ment than required, so that as much as possible of the 
scale 

25

 on the telescopic pipe remains visible.

– Retighten the wing bolt 

26

 again. Loosen the clamping screw 

23

 on the depth stop of the dust extraction attachment.

– Move the depth stop 

24

 on the telescopic pipe 

25

 in such 

a manner that the clearance

X

 shown in the figure corre-

sponds with the required drilling depth.

– Tighten  the  clamping  screw 

23

 in this position.

Operation

Starting Operation



Observe correct mains voltage! The voltage of the pow-
er source must agree with the voltage specified on the 
nameplate of the machine. 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 with the 
mode selector switch 

9

.

Note: 

Change the operating mode only when the machine is 

switched off! Otherwise, the machine can be damaged.

– To change the operating mode, push the release button 

8

and turn the mode selector switch 

9

 to the requested posi-

tion until it can be heard to latch.

Reversing the rotational direction

The rotational direction switch 

13

 is used to reverse the rota-

tional direction of the machine.



Actuate the rotational direction switch 13 only when 
the machine is at a standstill.

Right rotation: 

Turn the rotational direction switch 

13

 to 

the stop in position

.

Left rotation: 

Turn the rotational direction switch 

13

 to 

the stop in position

.

Set the direction of rotation for hammer drilling, drilling and 
chiselling always to right rotation.

Switching On and Off

– To 

start

 the machine, press the On/Off switch 

7

.

– To 

switch off

 the machine, release the On/Off switch 

7

.

To save energy, only switch the power tool on when using it.

Setting the Speed/Impact Rate

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.

Safety Clutch



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 loosen 
the tool insert. When switching the machine on with the 
drilling tool jammed, high reaction torques can occur.

Working Advice



Before any work on the machine itself, pull the mains 
plug.

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.
– Turn the mode selector switch 

9

 to the “Vario-Lock” posi-

tion (see “Setting the operating mode”, page 18).

– Turn the tool holder to the desired chiselling position.
– Turn the mode selector switch 

9

 to the “chiselling” posi-

tion. The tool holder is now locked.

– For chiselling, set the rotation direction to right rotation.

Inserting Screwdriver Bits (see figure L)



Apply the power tool to the screw/nut only when it is 
switched off. 

Rotating tool inserts can slip off.

To work with screwdriver bits, a universal bit holder 

28

 with 

SDS-plus shank (accessory) is required.

– Clean the shank end of the adapter shank and apply a light 

coat of grease.

– Insert the universal bit holder with a turning motion into 

the tool holder until it automatically locks.

– Check the locking effect by pulling the universal bit holder.
– Insert a screwdriver bit into the universal bit holder. Use 

only screwdriver bits that match the screw head.

– Turn the mode selector switch 

9

 to the “drilling” position.

– To remove the universal bit holder, pull the locking sleeve 

5

 toward the rear and remove the universal bit holder 

28

out of the tool holder.

Position for 

hammer drilling

 in concrete or 

stone

Position for 

drilling

 without impact in wood, 

metal, ceramic and plastic as well as for 
screwdriving

Vario-Lock

 position for adjustment of the 

chiselling position

The mode selector switch 

9

 does not latch in 

this position.

Position for 

chiselling

OBJ_BUCH-770-007.book  Page 18  Wednesday, October 2, 2013  10:37 AM