Yes, GB. I'm designing, in my head at the moment, a custom stop plate that fits between the derailleur upper body and the hanger. I will have to cut the stop off the derailleur, and maybe drill and tap a small hole in the back of the upper body to hold the plate in place, or maybe it will just be held in place when the derailleur is bolted down but I think it will have to be fixed in place. So far this is theoretical. If I actually start the process, I'll post.

I think they're pretty much the same. Is the 610 series the one that uses metal-shrouded plastic on the parallelogram, or am I thinking of the 410 series?

They both did. The 610 has the drop parallelogram.

About 1975, I did the conversion on my 1971 Gitane TdF. The Campy Kool-Aid was irresistible. Tap and ground. It was ground a little further than would have been perfect, but the bike and that 1974 NR RD are still going strong. I don't have a better picture of the drop-out, as this is now the bike I leave at my mother's house to ride on visits.



This photo is about 3 months old, taken after an overhaul and replacement of chainrings (52/38). Not a purist build, but I love this bike.

Ok. The SX660 is all metal, but not as well finished as the SLJs.

Thanks for a very interesting thread, guys. I would have had a similar question (Suntour on a Simplex?) in a few weeks as I get more into my PX-10. All this French stuff, c'est nouveau pour moi.

I have an intact Simplex Criterium RD, and a spare, and found a not-quite-correct but working Prestige FD, but that Delrin isn't getting any younger and it's good to have a backup plan.

Yeah, the Delrin isn't getting any younger, Al, though my Criterium rear seems to be still working fine. Just thought I'd slap some Nuovo Record parts on my Gitane. Till I got to the rear derailleur, that is.

So I've brain-stormed a possible adaptation and have a prototype replacement Campy upper bolt in the lathe at the moment. If this works I'll start a new thread on the making of the parts. No guarantee this is going to work, however. I'm a ham-fisted and totally amateur machinist.

Follow-up: I found a pic of my Simplex dropout, and it had been modified. Just long enough ago that I didn't remember, mainly because I acquired the frame with this modification having already been made. (pre-paint picture)