Quote:
Originally posted by Maxx Mazda
Unless you're in aviation, I've never seen the need to have a torque wrench calibrated. On every vehicle I've ever worked on, the factory service manual has always listed a torque range for every fastener for this very reason, that the wrench itself may be inaccurate by a few inch/foot pounds. Since wrenches will generally under torque instead of over torque (if they are even off) I usually set it to 2/3 of whatever the max torque specified in the manual is. So if the value called for is 95-100 lbf for example, I'll set the wrench to 98 and that will allow room for error.
Mechanical wrenches will always drift over usage and should be checked periodically - every 5 or 10 years is probably enough for most folks doing non-critical stuff. If you're using a strain-type wrench, they don't really drift AFAIK.