RE: Re: Torque-to-Yield Meaning

["Gilbert, Clark" <Clark_Gilbert@xxxxxxx>]

Torque to yield refers primarily to the process of tightening the bolt
such that it will never return to its original length. That is why you
should not re-use bolts torqued to that point. You have stressed the
metal beyond the elastic curve. When tightening a bolt beyond the
elastic limit, you will notice that the torque value no longer
increases, even though you are still turning the bolt head. In fact, on
mild steel bolts, the torque value will drop. I believe that this is the
point that most air-wrench jockeys look for when they are doing wheel
work on our beloved bimmers. =;^)

Clark

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