Quote Originally Posted by NTFDAY View Post
I'm now sorry that I brought this subject up. After working in the aircraft industry I guess I tend to err on the side of caution. At the time inspectors demanded that between two to four threads were visible past the end of a nut, but we were dealing with vibration issues which hopefully you won't be. Everything, generally, was either a locking type nut or castle nut. The castle nuts were for safety wiring purposes and most often found around the engines and they were also used on any exterior lighting.
This could be where Jerry is coming from since he spent most of his time in aircraft and running diggers and floppers.
Ken, there was absolutely nothing wrong with your comment. You saw something that raised a question in your mind, and you brought it to light as you should.

I spent four years in the Navy, trained in P & A schools as an Aviation Machinist's Mate for radial engines. I worked the aircraft line doing pre & post flight inspections, then worked the Powerplant Shop performing maintenance, and later doing QA/QC on the work done in our shop so I'm kind of aware of the aviation process, too. There are rules, and then there is application. One must consider the application in deciding how to apply the rules, and more to the point which rules actually apply, and which rules are not relevant to the situation which is what 36sedan said so well in his last post above. Jerry's general rule for tapped holes is a good, conservative rule for bolted joints pushing the tensile strength of the bolt, but it simply doesn't apply, IMO.

And now, unless someone wants to extend the discussion further, I'm done.