TORQUE TEST FIXTURE

Torque Tester

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Torque Measurement

Measurement and Calibration

The following information may help in selecting the appropriate measuring device for your needs.

Accuracy

The precision of the instrument which can be reported in three ways.
1. By quoting the guaranteed tolerance as a percentage of the reading or indicated value,
    (eg. “0.5% of Reading”).
2. By quoting the guaranteed tolerance as a percentage of the full scale value of the instrument,
    (eg. 0.1% FS or 0.1% FSD).
3. By quoting a ‘class’ of device in accordance with BS7882:2008
    “Method for calibration and classification of torque measuring devices”.
    (See page 90).

Modes of Operation

First Peak of Torque - when a “click type” torque wrench signals that the set torque has been achieved,
the applied torque will momentarily drop before climbing again. Generally the fastener stops rotating at
point 1, and from a standstill, the breakaway torque to achieve further rotation of the fastener will be higher than point 3b. Only if the operator is very insensitive to the break point will the final tightening effort be incorrect. “First Peak of Torque” mode will detect the break point of the torque wrench, not the highest torque applied.

Peak Torque

This mode of operation will record the highest torque applied. In the case of a “click type” torque wrench
this may be higher than the actual break point if the wrench continues to be loaded beyond the break. 
Consequently, Peak Torque is more useful for calibrating devices without a break signal such as dial
or electronic wrenches.

Track

This mode has no memory at all. When the load is removed the display will return to zero. 
Track is used for calibrating the device itself or for monitoring a fluctuating torque.