In a message dated 9/27/2001 10:27:15 PM Eastern Daylight Time,
millerb@netusa1.net writes:
> Noticed
> (felt) a missing bolt, replaced with a grade 8. Snapped within a month.
> Replaced with a grade 5 laying around the garage. That's been 5 years ago.
>
Bill:
Did you torque the Grade 8 at the recommended increased level of torque or at
the level of a grade 5? That would make a huge difference, since, according
to what I have read preload is more important in fastener failure than bolt
strength, as long as the minimum grade is used. If a grade 8 bolt is torqued
at the recommended torque of a grade 5, it is loose.
--David C.
|