Maintenance And Service - Bosch GBH 3-28 E PROFESSIONAL Operating Instructions Manual

OBJ_BUCH-188-001.book Page 19 Wednesday, September 13, 2006 4:55 PM
Position the the guide pipe 21 of the dust extraction
attachment 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 21 further over the telescopic pipe 19 of
the dust extraction attachment than required, so that
as much as possible of the scale 19 on the telescopic
pipe remains visible.
Retighten the wing bolt 20 again. Loosen the clamp-
ing screw 17 on the depth stop of the dust extraction
attachment.
Move the depth stop 18 on the telescopic pipe 19 in
such a manner that the clearance X shown in the fig-
ure corresponds with the required drilling depth.
Tighten the clamping screw 17 in this position.
Operation
Starting Operation
Observe correct mains voltage! The voltage
of the power 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
Actuate the selector switch for drilling/ham-
mer drilling 6 only when the power tool is at
a standstill.
Hammer drilling
Set the selector switch 6 to the "Hammer
drilling" symbols.
Drilling
Set the selector switch 6 to the "Drilling"
symbol.
Switching On and Off
To start the machine, press the On/Off switch 7 and
keep it depressed.
To switch off the machine, release the On/Off switch
7.
For low temperatures, the machine reaches the full
hammer/impact capacity only after a certain time.
This start-up time can be shortened by striking the
inserted tool insert against the floor one time.
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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/impact rate. Further pressure on the switch
increases the speed/impact rate.
Overload 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 switch-
ing the machine on with the drilling tool
jammed, high reaction torques can occur.

Maintenance and Service

Maintenance and Cleaning
Before any work on the machine itself, pull
the mains plug.
For safe and proper working, always keep
the machine and ventilation slots clean.
A damaged dust protection cap should be
changed immediately. We recommend hav-
ing this carried out by an after-sales service.
Lubrication
The power tool is oil-lubricated. An oil change is
required only within the scope of maintenance or
repair through an authorised after-sales service agent
for Bosch power tools. In this, it is absolutely required
to use the specified Bosch oil.
If the machine should fail despite the care taken in
manufacturing and testing procedures, repair should
be carried out by an after-sales service centre for
Bosch power tools.
In all correspondence and spare parts order, please
always include the 10-digit article number given on
the type plate of the machine.
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