Join Date: Aug 2009
Location: Washington, the state
See if you can remove an end cap on the handle of your torque wrench and find an adjuster under there. Adjust the torque wrench for the middle of the scale, then test it to see how close it is at 10% and 90% of the scale. It probably only needs to be professionally calibrated if you're overhauling a gas turbine or something like that.
Yes, the torque spec depends on the thread pitch, the material of the bolt and the base metal, the surface finish of the threads, and the type of lubrication if any--all these effect the friction of the threads which absorbs much of the torque. You are right to torque lots of things until you acquire the feel for tightening. I've know some who try to twist off every bolt they tighten and others who have no idea that they aren't nearly tight enough. I've seen torque specs for things like medium sized diesel head bolts that called for two men on a six foot bar....
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