My theory on lug nut and wheel stud failure: It's cause by mechanics
using impact guns to remove the nuts. After the nut is disengaged, the
gun spins it very quickly with the ends of the threads touching each
other. This is especially bad if the socket is short and the nut is
bottomed out, so the force of the mechanic pushing is transferred to the
end threads. This slowly damages the threads at a critical point -
where they start mating. Eventually the damage starts being transferred
down the length of the thread due to this damage.
--
Mike F.
Thornhill (near Toronto), Ont.
Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)
