User Manual

FACTORS AFFECTING TIGHTENING TORQUE
1. Voltage
A drop in voltage causes a reduction in motor speed, the force and number of impacts,
and tightening torque.
2. Tightening time
*The tightening time affects the number of impacts.
Thus, the torque increases with
time of tightening.
* Long tightening eventually means no more increase in tightening torque, since the
tool hammer’s tightening force and the foroe of the bolt or nut cancel each other
out.
3. Socket
Failure to use the correct socket size will result in torque that is not even.
*Stable torque
is not possible with a worn socket (wear on the hex end or anvil square
end).
4. Different torque even with the same diameter bolt
*The proper tightening torque differs (even for
a bolt of the same diameter) in terms
of the torque coefficient: screw effective diameter, wear angle, lead angle, average
diameter of nut surface and the wear coefficient on the nut surface.
*The type (class) bolt makes for
a different tightening torque.
*The time for tightening varies in terms of bolt length.
*The torque differs in terms of installation place also.
*The manner of holding the tool will affect the torque..
5. Bolts of different diameters
Even though the torque coefficient and class of bolt are the same, the torque will vary
with bolts of different diameters.
6. Torque measuring method
The tightening torque will even differ depending on the way of measuring
it.
7. Use of accessories
The use of the extension bar somewhat reduces the tightening force of the impact
wrench. Compensate
by tightening for a longer time.
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