[TR] Bolt Grade

[Randall]

> A friend wants to replace
> this bolt with a US equivalent

I can't answer your question, Alex, just wanted to point out that there may
be more to that bolt than just grade.  For example, TR driveshaft bolts have
a particular diameter and length of unthreaded shank, and unusually short
threads.

IMO it's unlikely to be any stronger than SAE grade 5, but that's just a
guess.  One way to estimate it is to look at the torque spec.  Standard
torque for a grade 5 7/16-20 is 75 ft-lb.  If the specified torque is less
than 75, it's probably less than a Grade 5 bolt.

Randall