Tom--

Maybe you just think you galled/stripped the threads. The actual female threads are steel nutplates into which the 1/2" AN spar bolts are screwed. They're hidden behind the spar closeout webs so you can't see them. The spar bolts pass through aluminum sleeves (called bolt bushings) which support the shank of the bolt so I'm thinking that maybe it is one of those sleeves which has some thread marks on it that you are seeing. Here are the details from the construction manual



If it's the bolt bushings which are badly messed up, you can always drill out the old ones and glue in new ones using the original procedure in the plans. If it really is the steel nutplate that is badly messed up, the only option I can think of is to cut a hole in the spar closeout web and replace the nutplate itself. I would consult the factory on how to do that and patch up the hole when you were done. I'd consult the factory anyway...

I just removed my wings for painting only to find I badly galled/stripped the aluminum threads on the spar side. I am not sure what my options perhaps helicoils but how to drill the hole perfectly straight and are they strong enough.  Any advice here would be very welcome.  I am in somewhat of a desperate situation not knowing if I can safely rectify this problem.