Originally Posted by
dedhed
FWIW the freewheel appears to be French threaded.
The stamped threading reads "1.375 x 24TPI", which is
ISO threading. It was intended to split the difference between, and be compatible with both British (1.370") and Italian (35mm/1.378") 24tpi freewheel hubs. French freewheel threads are 34.7mm x 1.0mm. Hopefully the hub is not French threaded.
(Edited to correct typo)