Most people don't realize that the major diameter of a thread is very close to the minor diameter of the next size. So where 3/8" threads are totally stripped the hole is now very close to the drill diameter req'd for a 7/16" tap.
I would hate to try getting a 7/16 bolt in some of these holes that are close to runners. Heck I have to get the correct length bolts with 12 point heads on
Many of mine.
