Maintenance And Service; Working Instructions - Bosch Professional GBH 5-38 D Operating Instructions Manual

OBJ_BUCH-436-001.book Page 10 Friday, July 13, 2007 11:42 AM
10 | English
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 power tool on with the drilling tool
jammed, high reaction torques can occur.
Changing the Chiselling Position (Vario-Lock)
The chisel can be locked in 12 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 3 to the "Vario-
Lock" position (see "Setting the Operating
Mode", page 9).
Turn the tool holder to the requested chiselling
position.
Turn the mode selector switch 3 to the chiseling
position. The tool holder is now locked.
The mode selector switch 3 must always be
locked in the "Chiselling" position when
chiselling.

Working Instructions

Sharpening Chisels (see figure C)
Good results are only achieved with sharp chis-
els; therefore, sharpen the chiselling tools in
good time. This ensures a long service life of the
tools and good working performance.
Re-sharpening
Sharpen chiselling tools using grinding wheels
(e. g. ceramic bonded corundum wheel) with a
steady supply of water. Reference values are
shown in the figure. Take care that no annealing
coloration appears on the cutting edges; this im-
pairs the hardness of the chiselling tools.
For forging, heat the chisel to between 850 and
1050 °C (bright red to yellow).
For hardening, heat the chisel to approx. 900 °C
and quench in oil. Then anneal in an oven for ap-
prox. one hour at 320 °C (annealing color = light
blue).
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Maintenance and Service

Maintenance and Cleaning
Before any work on the power tool itself,
pull the mains plug.
For safe and proper working, always keep
the power tool and the 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 authorized after-sales service
agent for Bosch power tools. In this, it is abso-
lutely required to use the specified Bosch oil.
If the power tool should fail despite the care tak-
en in manufacturing and testing procedures, re-
pair should be carried out by an after-sales ser-
vice center for Bosch power tools.
In all correspondence and spare parts orders,
please always include the 10-digit article number
given on the type plate of the power tool.
Bosch Power Tools