Originally Posted by
jiangshi
It appears to have two grooves in the back, that is French.
Originally Posted by
T-Mar
The freewheel threading standard would be marked on the back on the body, not the cogs, as the cogs are interchangeable. Regina used F.F. or 2 grooves to signify French threading depending on the era. It's hard to tell in the photo, if the body has 2 grooves (French) or 3 grooves (ISO). What appears to be a 3rd groove may just be the thread start.
OK, that's potentially very helpful. Looking back at my pictures, one of the freewheels that was hand-marked as "FF" is a Japanese (SunTour?) 7-speed freewheel, which seems fairly unlikely to be French threaded, so maybe that was the one I'm remembering as having threaded smoothly onto an ISO hub in spite of the "FF" mark.
I'll look closely at the grooves when I get home. For now, I have these additional pictures of one of them. It looks like one groove, so Italian threading?
And then this was the 7-speed freewheel:
