In a message dated 97-10-09 16:18:15 EDT, dgibbons@PRESRAY.COM writes:

<< In theory any bolt only needs 1 or 2 threads to develop full strength. In
 practice its best to have at 1 diameter of threads sticking out the nut.  >>

Actually the theory calls for at least 3 threads to make the shear strength
of the threads equal to the tensile strength of the stud.  Still, 3 threads
doens't "seem" enough to be.  I too, am comforted by at least one diameter's
worth of engagement.

Regards,
Jim Davis