This has turned into a comedy of "expert" advice that makes no sense at all to me. The screw is for a simple mudguard strut !

It doesn't need threads at all. Drill out the fastener whether it is perfectly on-center or not. Just put a gol-darn 5.5mm hole in the dropout and use a allen screw and a nylok bolt.

I'm shaking my head here. Whats next ? Start sending him to find an EDM shop ?

It's a goddamn bicycle, not the Space Shuttle !