If someone tells you an Italian hub shell is English thread say "How do you know?". If there is a specific marking, fine. If they say I got out my micrometer and it measures 1.370" as opposed to 1.378", fine. Otherwise you can just as well have an Italian thread. Same pitch, different thread form. Higher crest on the Italian, I would guess a deeper root and I believe there is a slight difference in thread angle of 55 degrees (maybe the Italian) and 60 degrees (maybe the English). Forgive me as Sutherland's skates around this thread angle stuff and my memory- forget it.
Actually, I think the thread grinding idea is a A1 mechanically. All these little dimensional differences are about industrial tolerences and you are just taking off the high spots to create more uniform loading. Just beware of loose fits should you switch parts around.
Joe Bender-Zanoni Great Notch, NJ
Philip Easton wrote:
> Hi All, As I recall there was a discussion a while ago re. freewheels
> tightening up as they were threaded onto the hub. I had this problem
> last night when trying to thread a Cyclo three speed freewheel onto a
> NOS Gnutti small flange hub. The hub was supposed to be English
> thread and if I tested it with a fixed cog the cog spun on freely.
> The three speed freewheel also threaded very freely on an Airlite and
> a Harden hub. I tested with another English thread freewheel and had
> a similar binding problem. As in the past I put some grinding paste
> on the threads and eventually got the second freewheel to go on and
> come off easily, but of course the three speed freewheel I want to use
> still stuck at about the half way point. Thinking that maybe there
> was a slight taper on the freewheel threads I reversed the freewheel
> (small cog inboard) and started to thread it on (still using grinding
> paste) after some initial resistance and using the freewheel as a die
> and backing off continuously it suddenly turned freely all the way on
> the hub. I cleaned of all the paste taking care not to wash it in the
> bearings, and took a look at the threads which appeared undamaged, and
> the freewheel now beds solidly on the hub. Not a method that would
> get you into the Bicycle Engineering Hall of Fame, but it worked. All
> the best from sometime foggy, sometime sunny Cambria, California