Lehner 1950 end cap help!!!

[Purplefade]

I'd have to go with cemetery gates, pop the end off and tap them to 4mm, any chance that might work? I know some of the larger can motors already run 4mm screws, why not yours too.

Thinking crazy, I've seen very small helicoils work on a huge number of things. If they'll hold nitro funny car heads on I'd have to believe that they'll hold a brushless motor in place??