Hmm,
What grade of bolts were they using?
CR
DLancer7676@cs.com wrote:
>
> While we are on torque wrench discussion, I attended a "Fastner" workshop at
> the Conclave in Indy this past summer. It was truly fascinating. One bit of
> information I learned, and saw demonstrated with load measuring devices, is
> how much strength a bolt loses after it is torqued only once! When you
> torque a nut or bolt to specs the first time, you reach a certain level of
> pre-load, say 17,000 ft/lb. If you loosen that same nut or bolt, then
> retorque it a 2nd time to proper torque, it will pre-load only to about
> 12,000-13,000 ft./lb. And it drops with each successive loosening and
> retightening. A real case for not reusing bolts in critical safety usages.
>
> It made me think, and shudder, at the number of times a wheel stud and bolt
> are loosened and torqued over its lifetime. Not very often do we change out
> our wheel studs, but they have to be running at only a fraction of their
> original strength.
>
> --David C.
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