Gene Kearns wrote:
You said, "The engagement, or amount of material 'gripping' between
bolt & stud, will be approx twice as much. "

Oh, I thought you were objecting to the "less tendency to loosen due to
vibration" statement. That's out of the ASCME handbook too but right now
I don't have time to do a big web search. If you've read all the
references I posted then by now your knowledge is probably greater &
more up to date than mine.



The only reason the fastener might be stronger, in any way, is that
the minor diameter is greater on a fine threaded bolt than on a
coarse thread...

The difference in root diameter & major diameter, factored by how
closely the pitch is machined, determines how much of each thread is
engaged. Another factor is that for a given size bolt, the fine thread
will have more threads per unit length and this will act to multiply the
engaged length of thread. Plus, fine threads are usually machined to
closer tolerance.


.... this is, of course, countered by the fact that a
fine threaded bolt is easier to strip. Nearly all decent bolts will
strip before they break in tension.

That's not been my experience. Maybe i haven't been using "decent" bolts?




While there may be some minimal advantage to a fine threaded bolt not
backing out... this is minimized to the point of irrelevance by proper
fastener-locking technology.

Again, not true in my experience. I'd generally prefer to use double
bolts and antisieze than lock washers, self lockers, or Loc-Tite
(although it's truly marvelous stuff).

Fair Skies
Doug King