On Sunday, April 5, 2015 at 10:34:56 AM UTC-4, Lloyd E. Sponenburgh wrote in rev.crafts.metalworking:
Ignoramus10114 fired this volley in
> news: snipped-for-privacy@giganews.com:
>
> > strength not an issue
> >
>
> Then one sizes it according to what you want to mount.
>
> I mentioned 2.5x.45 metric... some also use 3 x 0.5mm, but even
> that's smaller than 6-32.
>
> If you need to mount through screw insulators (like for mounting
> a transistor or a floating-case regulator like an LM-317, you may
> be hard-put to find any insulators that will fit even 6-32... metric
> has more-or-less filled that market.
With a rapidly expanding international market where demand for metric outstrips demand for trade (in everyplace but the US), its not surprising.