Breaking In a Dial Type Torque Wrench

[rusty_ratchet]

I just bought a CDI 3002LDIN torque wrench. It's a dial type which I haven't used before, and the users manual states the following:

"Before using all models of dial torque wrenches, it is strongly suggested to cycle/operate them 3 times at full scale in the torque direction in which they will be used."


Is this as straightforward as it sounds? I just find a bolt and torque it to full scale three times? What is the purpose of doing this?

 

[country83]

It's used to "prestress" the wrench which will make for more consistent readings. It's a good idea to do this when switching directions, too.

 

[guy48065]

Metal has "hysteresis"--which is a reluctance to cross through zero at the same point, in both directions. In practice you start with the dial zeroed, torque it to full scale CW (for example), then you need to re-zero but usually not again as long as you continue to torque CW.