Bosch GBH Professional 5-38 D Original Instructions Manual page 19

OBJ_BUCH-273-002.book Page 19 Tuesday, June 22, 2010 11:24 AM
Safety Clutch
If the tool insert becomes caught or
jammed, the drive to the drill spindle is in-
terrupted. 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.
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 Oper-
ating Mode", page 18).
– Turn the tool holder to the desired chiselling
position.
– Turn the mode selector switch 3 to the "chis-
elling" position. The tool holder is now
locked.
The mode selector switch 3 must always be
locked in the "Chiselling" position when
chiselling.
Working Advice
Before any work on the machine itself, pull
the mains plug.
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. Refer-
ence values are shown in the figure. Take
care that no annealing coloration appears on
the cutting edges; this impairs the hardness
of the chiselling tools.
– For forging, heat the chisel to between 850
and 1050 °C (bright red to yellow).
Bosch Power Tools
– For hardening, heat the chisel to approx.
900 °C and quench in oil. Then anneal in an
oven for approx. one hour at 320 °C (anneal-
ing colour = light blue).
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 serv-
ice.
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 serv-
ice agent for Bosch power tools. In this, it is ab-
solutely 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.
After-sales Service and Customer
Assistance
Our after-sales service responds to your ques-
tions concerning maintenance and repair of your
product as well as spare parts. Exploded views
and information on spare parts can also be
found under:
www.bosch-pt.com
Our customer service representatives can an-
swer your questions concerning possible appli-
cations and adjustment of products and acces-
sories.
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