Pete. (l33t FS) said:Somewhere I recall that only a small number of the threads are actually under any load, no matter how long the threads are. (6 or 7 threads?) It's something to do with how the externally threaded component stretches when loaded while the internally threaded component compresses very slightly.
This IS nice from a soft-failure point of view, as if those threads yield, the load passes to the next ones up the line, albeit with a lessening of load on the fastener.
I've read that for steel threads, I don't know if the same thing applies to aluminum. The stiffness of the material is different, so perhaps it deforms a smaller amount over a longer distance? Then again the stud is still steel and maybe taht's where most of the deformation happens. I dunno, I'm not an ME. :)
One nice thing about having the stud come out the back of the nut is that it's a quick way to avoid having to count turns when you put the nut on to make sure you've got enough.
