Mike,
Huret adjuster screws and the like definitely aren't fractional.
Along with threaded "fasteners" like those coarse-pitch, 5mm Simplex shifter screws, metric hardware was made in an annoying variety of pitch sizes for particular applications where a coarser or finer pitch was desired for functional reasons. I've used 10-24 screws to attach modern, off-topic levers to those Simplex clamps, but the American hardware ends up depending on Loctite to assure retention. A derailer's adjuster screw probably sees smaller loads so maybe this is a case of finding "whatever works". A compression spring might work well enough to help retain adjustment, and I notice that 4-40 hardware is very close in pitch and just .2mm smaller in diameter.
In my "really odd threaded hardware" box, I find a couple of M3x0.6 chromed, round-head slotted screws, each 15mm long. Would that work? And, do you have, or can you link to, a picture of the special clamp washer?
Lastly, if any French parts hoarders out there have a toothed, adjustable Huret derailer guide pulley, any color, I'd very much like to buy one.
David Snyder Auburn, CA usa
> Dear Listees,
>
> I have a rear Jubillee derailleur that is missing one of the adjuster
> screws, along with the cable clamp washer.
>
> The Huret adjuster screw is about the size of a rear dropout adjuster
> screw (M3 x .5), with a slightly more coarse thread pitch. It appears to
> be a fractional size - it doesn't match up to any of the fine pitch blades
> on my metric thread gauge. Very weird. I'll check it with a fractional
> gauge as soon as I can find mine. Haven't used the fractional one in a
> while.
> Does anyone have these bits around ? Maybe a crunched / twisted
> derailleur?
> Please let me know off-list and lets work out a deal.
>
> Thanks,
> Mike Fabian
> San Francisco, CA, USA