Stripped Threads

I spend a lot of time fixing threads, caused mostly by over tightening.  May I suggest using nylon insert locknuts, jam nuts, flange lock nuts, serrated lock nuts, loc-tite, prevailing torque lock nuts, cage nuts or hex pal nuts or even pushnut bolt retainers???????

Above: This happens when the bolt & nut are junk(and too soft) to start out with . . .

The Keensert (left) is the best, but it's easy to fart it up.  The pins don't always drive the easiest, and sometimes it's hard to get them all the way down.  Once it's in - it's done and solid.  If your hole is way oversize, the Keensert may be your only option.
The Nutsert or Timesert (center) is good too.  I like the top "flange" that gives a surface to tighten against.  They are available in "oversize/oversize" when even the Heli-Coil failed. 
I use the Heli-Coil (right) most often.  Simple to use and works great in aluminum.  If you follow the directions, take your time and get it correct, the heli-coil has saved people thousands of dollars and prevented lots of warpage from welding and high heat, trying to weld up and redrill.

All these motors I work on, usually have a lot of this . . .

Speaking of stripped threads . . .

Heather Thomas, 80s heart-throb for old dudes.

She still looks pretty good... (for a 60)