I'm an EE so this is outside my area, but....
While looking at with a friend [his PhD is chemistry, and he writes crypto code, so no help THERE..] we go onto thread strength.
My recollection was the rule was "With good threads, the rod shall break {in pure tension} before the threads fail" but I do not know where that came from. I seem to recall that was based on a nut depth GT/EQ to one diameter as well....
But I've never seen such written down. How right/wrong am I?