Maintenance
13
Maintenance
The internal mechanisms of the torque wrench are
subject to normal wear and tear under operating
conditions. For this reason, the accuracy of the cut-
out should be checked at regular intervals.
If not specified by internal regulations of the
operator (e. g. test equipment monitoring according
to ISO 9000 ff), we recommend an inspection
according to DIN EN ISO 6789, i.e. after approx.
5000 cut-outs or after 12 months, whichever occurs
first. The period (12 months) starts with the initial
commissioning.
If inspection shows that there is a deviation, the
torque wrench must be adjusted.
The inspection and adjustment must be carried out
in accordance with DIN EN ISO 6789.
Checking the accuracy of the cut-out
value
To check the torque, a torque tester with the right
capacity is required which has an accuracy of ±1 %
of the displayed value or better.
If you have access to such a tester, you may
inspect the MANOSKOP
®
yourself. Suitable torque
testers are available from STAHLWILLE. It is also
possible for STAHLWILLE to test the MANOSKOP
®
for you.
To carry out the test, proceed as follows:
Set the torque wrench to the highest scale
reading.
Operate the torque wrench five times ensuring it
cuts out properly each time.
Important note on the accuracy of the readings:
ATTENTION!
Incorrect use of the torque wrench
leads to the risk of material damage.
Under no circumstances continue
tightening the screw connection after
the torque wrench has cut-out.
In the following example a MANOSKOP
®
730/10 Quick is used.
Set the torque wrench to 20 % of the maximum
scale reading.
Use this setting to perform five measurements on
the torque tester.
Use the following formula to make sure that the
values displayed by the torque tester do not
deviate by more than ±4 %.
A=deviation in %
W1=value set on the Manoskop
W2=tester measured value
