"Damaged holes in tapped threads necessitate replacement of cylinder head" I guess this was before Heli-Coils or TIme-Serts, eh? I've also fixed stripped threads in old metal things by brazing in a new layer and tapping that out . There are a number of old steel bicycles in my area that are running with brazed and retooled derailleur hanger threads-versus throwing the frame away or <gag> making into a hipster single speed. Sometimes I have to fabricate the whole derailleur hanger.. whether old cars or bikes, sometimes we have to make it ourselves :-)
