Quote:
Originally Posted by Mr V
The rule of thumb for thread engagement is in hard materials like steel you want 1x the bolt diameter and for soft materials like aluminum you want 2x the bolt diameter. That does not change whether you are using coarse or fine threads. If you look at standard steel nuts you'll find that their height is 1x the bolt diameter. So going to 10-32 to get more thread engagement isn't really gaining you anything in fact if it is in Aluminum you are more likely to strip the threads out of the item that you have tapped.
The only real advantages that find thread have are the the bolt itself is slightly stronger and that it is slightly less prone to loosening from vibration.
http://www.bestbolt.com/white_papers/white_paper_08.pdf |
We're usually not tapping into aluminum when 10-32 were used. One way we used the 10-32 last year was in our chain tensioning system. We fed the 10-32 bolt into a helicoil. If we're tapping into aluminum, it usually is UNC. By far, 10-24 is the most common bolt we use. A recent exception was in an experimental drivetrain, because the only #10 SHCS we had was #10-32, and we needed that size and head type.