The true design of a fastener has a "torque value". This is the value calculated by engineering and is quite accurate. But the best way is to tighten a fastener by hand and "feel" when the threads do their work. I shocked some engineers one day when I told them that I would prefer the mechanic working on my car to under torque all the hardware rather than over torque it. Why? Because if it is under tightened it has the ability to warn you that it is loosening (rattle, shudder, etc.) where as if it is over tightened then the fastener fails outright and off goes the wheel. I've seen examples of failures due to over torquing including broken aircraft engine crank shafts, broken bicycle axle, and a wheel from my friends work truck falling off (luckily) in his driveway.


"BRAAAAAAAPPPPPP!!!! "That wheel ain't comin' off!" I hear that and I get a very strong urge to grab my tire iron and adjust someone's brain case. It ain't distraction, it ain't multi-tasking it *is* stupid, unnecessary and dangerous.