Adam Rush wrote:
> > That gauge is mostly useful to Raleigh & other vintage UK
> > bikes and the Roadster clones of Asia.
> > If you can only get the WW model it is still useful on SAE
> > threads and covers our common 24, 26, 28 tpi. Even with the
> > difference of form a WW gauge is plenty accurate to tell a
> > 24 from a 26.
>
> Okay, that's really good to know. What is the least painful way to
> measure diameter?
>
Calipers. Dial calipers are good, digital are better (plus you can
toggle
between metric and English with most of them).
> > Look for one with SAE and metric, which the French snootily
> > call "SI".
> >
> > In standard DIN metric for example a 5mm bolt has a pitch of
> > 0.8 with an 8mm wrench flat. The French version is 0.9 with
> > a 9mm wrench. Some "system internationale", eh?
>
> Wow.
>
> > When you say "need to identify some threading on a bicycle"
> > which threads? For many problems a thread gauge isn't all
> > that useful. For axle sets it surely helps.
>
> I'm getting an old Swedish army bicycle soon and would like to make an
> online guide to its maintenance. The problem is that, at that point in
> time, there is no telling which threading standard(s) they used, and
> the documentation is quite hard to come by. It could be any threading
> system, really, except for the American ones. I'm looking to identify
> all of the threads.
Adam, when I gave you my earlier answer, I just googled [Whitworth UNC
UNF].
It came back with pages and pages of reference sites. If you do
this you
are bound to find what you are looking for.
I have spent most of my life building engineering prototypes for
electromechanical
devices and, as a result, have spent a lot of time working with
machinists. When you give them an unknown threaded device they do
two things. First, they break out the calipers and measure the
diameter (O.D. for screws/axles/etc, and I.D. for nuts and the like),
and then they break out the thread pitch gauge and check the thread.
Measuring a diameter can be ambiguous, as to whether it's metric or
English, but thread pitches don't lie. Some the older British types
have different angles to the threads themselves and any decent
machinist is going to see this right away.