Working Advice - Bosch Professional GDR 9,6 V Manual Original

OBJ_BUCH-595-001.book Page 21 Monday, November 12, 2007 4:15 PM
Adjusting the Speed
The speed of the switched on power tool can be
variably adjusted, depending on how far the
On/Off switch 9 is pressed.
Light pressure on the On/Off switch 9 results in
a low rotational speed. Further pressure on the
switch results in an increase in speed.
Swivel Lighting System (see figure C)
Your tool is equipped with a light source in the
knurled thumbwheel 7. The light is activated as
soon as the knurled thumbwheel 7 is in position
1 – 3 and the On/Off switch 9 is pressed.
Depending on the bit being used, the light beam
can be adjusted to three positions by turning the
knurled thumbwheel 7. In position 1, the focus of
the light beam is approx. 20 mm, in position 2 ap-
prox. 150 mm and in position 3 approx. 500 mm
in front of the tool holder 1.
In the "OFF" position, the light is switched off
permanently.

Working Advice

Apply the power tool to the screw/nut only
when it is switched off. Rotating tool inserts
can slip off.
The torque depends on the impact duration. The
maximum achieved torque results from the sum
of all individual torques achieved through impact.
The maximum torque is achieved after an impact
duration of 6–10 seconds. After this duration,
the tightening torque is increased only minimally.
The impact duration is to be determined for each
required tightening torque. The actually achieved
tightening torque is always to be checked with a
torque wrench.
Screw Applications with Hard, Spring-loaded or
Soft Seat
When in a test, the achieved torques in an impact
series are measured and transferred into a dia-
gram, resulting in the curve of a torque character-
istic. The height of the curve corresponds with
the maximum reachable torque, and the steep-
ness indicates the duration in which this is
achieved.
Bosch Power Tools
A torque gradient depends on the following fac-
tors:
– Strength properties of the screws/nuts
– Type of backing (washer, disc spring, seal)
– Strength properties of the material being
screwed/bolted together
– Lubrication conditions at the screw/bolt con-
nection
The following application cases result according-
ly:
– A hard seat is given for metal-to-metal screw
applications with the use of washers. After a
relatively short impact duration, the maximum
torque is reached (steep characteristic
curve). Unnecessary long impact duration on-
ly causes damage to the machine.
– A spring-loaded seat is given for metal-to-
metal screw applications, however with the
use of spring washers, disc springs, studs or
screws/nuts with conical seat as well as when
using extensions.
– A soft seat is given for screw applications,
e. g., metal on wood or when using lead wash-
ers or fibre washers as backing.
For a spring-loaded seat as well as for a soft seat,
the maximum tightening torque is lower than for
a hard seat. Also, a clearly longer impact duration
is required.
1 609 929 M67 | (12.11.07)
English | 21