Bosch GDS 24 Professional Notice Originale page 17

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.
Determining the Impact Duration
The diagrams (examples) indicate that the tight-
ening torque [Nm] depends on the impact dura-
tion [s]:
For a hard seat
For a soft seat.
The data are mean values and vary depending on
the application. As a control measure, always
check the tightening torque with a torque
wrench.
Bosch Power Tools
Diagram for GDS 24
[Nm]
The highest torque is achieved:
– for a hard seat after approx. 10 seconds of im-
pact
– for a soft seat after approx. 22 seconds of im-
pact
Diagram for GDS 30
[Nm]
The highest torque is achieved:
– for a hard seat after approx. 6 seconds of im-
pact
– for a soft seat after approx. 26 seconds of im-
pact
For reference values for the maximum tightening
torques of commercially available screw/bolts,
see the following table.
English | 17
1
2
[s]
1
2
[s]
1 609 929 M73 | (24.10.07)