Hi Joel,
Regarding problem the first, the bike may be intended for Simplex Tourist 28 D derailleur. The 28 D is a variation of the 303 which bolts to a chainstay plate like the Rigidex you have. The cable stop on the 28 D is on a plate that mounts to the chainstay plate, so it would be behind the stop brazed on the frame. The 28 D uses a cage tension spring inside of the volute spring like a TdF rather than a screen door spring under the stay. Does your frame have a braze-on for the screen door spring? If it does, then the 28 D is not the right derailleur. Huret made some stay mount derailleurs too, but I don't know anything about them.
Leonard Bulger (assembling a French bike in rainy Marblehead)
Joel Metz wrote:
the rear dropouts/chainstay of my 1949 jack taylor tourist, in the process of being built up (slow process), with a simplex type juy touriste rear derailleur, look like this:
http://www.blackbirdsf.org/
as you can see, the path that the derailleur cable would take to enter the rear derailleur places it *forward* of the cable stop! the only present solution would be to loop the cable from the stop up, forward, and over itself to reach the derailleur. clearly, this is Not Right. so, it looks like im ruling out the simplex juy touriste.
i am, however, looking for thoughts as to what kind of rear derailleur this may well have been set up with! would i perhaps be better off looking at a single-cable cyclo randonneur type? the cable routing all points to a single-cable setup. theres a somewhat kludged hook for the external return spring, but its way forward, under the bottom bracket, which is much longer than the standard return springs for either the cyclo or the simplex...