Originally Posted by
dsbrantjr
I think that older Peugeots, like the OP's '75 PX 10, are French, not Swiss threaded. I could be wrong and there are ways to sometimes tell by the markings on the cups. My mid 70s Peugeot PR 10 is French threaded.
Alternatively (if the BB is Swiss), IRD makes swiss conversion cups that you can use on their bottom brackets.
https://www.interlocracing.com/shop/...bottom+bracket