Auditing Torque Applications

19/05/2014

Question:

How do I find how tight a previously tightened fastener was tightened too?

 

Answer:

There are 3 tests that can be used.

They all require a torque measuring tools such as a dial wrench or TT screwdriver

  • The first of the three tests is the marking test. The marking test is used to verify the torque of a previously tightened fastener. This is done by making a clear mark on the surface of the nut, bolt or screw and continuing the mark onto the surface being clamped. This acts as a reference point. The fastener may then be untightened and then retightened until the marks are again in line. The torque value can then be read from the torque tool display
  • The second of the tests is the just move test. Again this test is used to determine the torque setting of a previously tightened fastener. Using a torque measuring tool, a tightening torque is applied to the fastener until movement is just seen or felt. This torque is deemed to be a good indication of the original torque applied to the fastener
  • The third and last test is the break loose test. The break loose test is another method of checking the torque applied to a previously tightened fastener. Torque is applied in the direction that loosens the fastener, at the point the fastener breaks loose, the torque is recorded. This value is an indication of the torque at which the fastener was originally tightened. This value is typically 20-30% lower than the tightening torque
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