just so you (or I !) don't think I'm going
doolally, pictures below of the M3 x 35, S/S bolts fitted to my clear lenses -
It may be that, as suggested, there are different metric/UNC versions in use ?
I also wondered, given how soft the brass 'top hat' fitting is, whether the new metric bolts cut their own thread....?
'tis a mystery......
James