Greg,

I've made some repairs to German built gliders in the past. One
installation I have seen from the factory is to take a section of
brass rod approx 3/8" in diameter and drill and tap it. Knurl the
outside with a lathe and bond it in with the same epoxy as the
structure. No way will it pull out. If the threads happen to strip,
insert a helicoil.

All this is predicated on having thick enough material to make it
work.