For whatever it's worth... the screw used with those brazed-on French FD mounts was the same 5mm screw as used with water bottle cage mounting bosses. This size screw was also used with those slotted seat posts that were help in place with a set screw.
Fred Rednor - Arlington, Virginia (USA)
> To: "K.R. Bennett" <kerriganbennett@comcast.net>
> Cc: Classicrendezvous@bikelist.org
> Date: Tuesday, December 16, 2008, 6:34 PM
> Here's some photos of Simplex BO FDs variously badged
> Simplex, Gipiemme and
> Spidel plus one Italian Gipiemme FD for the more common FD
> BO.
>
> http://picasaweb.google.com/
>
> Kurt Sperry
> Bellingham Washington USA
>
> 2008/12/16 K.R. Bennett <kerriganbennett@comcast.net>
>
> > There is a Simplex front derailleur braze-on fitting
> that looks like an H2O
> > boss, except I think it's 6mm. Not sure if other
> French makers used the
> > same format.
> > See the fourth picture from the top here:
> >
> >
> >
> http://www.gitaneusa.com/