Really nice work. Higher temp brazing alloys damage chrome plating. Must have been done with lower melting temperature material???

Back in the early 70's several IDIOT hammersmiths published articles on how to castrate Simplex dropouts so that someone could mount a Campagnolo RD with a claw hanger.

1972 Article


1973 Bike World Article


What a stupid way of doing things?

Back in the early 70's before the all metal Simplex Super LJ derailleurs came on the scene, most of the French bikes with proprietary Simplex dropouts were mid range models like the Gitane Tour de France and Peugeot PX-10s.

Those bikes were not considered anything special and there was so much negativity towards plastic Simplex derailleurs that modifying Simplex derailleur hangers to use Campy or Suntour RDs was de rigueur!

The solution was simple (as Simplex). File a notch for the travel stop at the rear and thread the original 9mm mounting hole with an M10 x 1mm or 10mm x 26 tpi tap. The thread pitches are so close that either tap worked. M10 x 1mm tap is a standard for a lot of spark plugs. They're available for $10 USD or less at auto parts or hardware store.

15-20 minutes of work!

One other thing, the modification still allows Simplex derailleurs to be mounted on those dropouts without any problems. The minor diameter for those 10mm threads is 9mm, the same as the original hole size so the Simplex rear mount bolt still works!