At 04:31 PM 3/12/2009, you wrote:
>--- In 80f5@yahoogroups.com, Whitney Turner <wturner@...> wrote:
> >
> > Those may be M6 - double check before tightening too hard... M6 has
> > a 25.4TPI thread (1.0MM pitch) and is a little bigger than 12-24, so
> > there may be a one-way fit pseudo-compatibility, but there won't be
> > good thread engagement.
> >
> > ***********************
> >
>Thank you. I answered my own question by discovering (trial and error
>without any metric screws in my took kit) that the 12-24 screw did go
>in. How would I know if there is, or is not, good thread engagement with it?
>
>Gene

Gene,

I would hazard a guess that it isn't a #12-24 machine screw. That is an
uncommon size today even here in America.

While I don't own a Skywatcher myself, I would assume that the only English
thread size on it would be the 1/4"-20 tripod socket thread. Its pretty
safe to assume that everyone else on the planet uses the metric system.
Pity that we will never get aligned with the rest of the world in this
regard...

As for determining the size the best way is to get your hand on a M6 x 1.0
screw for a trial fit. Any decent hardware store should have one, this is
the Metric equivalent size to the ubiquitous 1/4"-20. As Whitney mentioned
the M6 major diameter is larger, by ~ .020" (or .5 mm if you prefer). The
#12 will likely thread in but it would be a loose fit.

Clear Skies,

Phil Lefever