Due to an aluminum dropout I don't wish to ruin on a first or second year Alan, I wonder if other on-topic 1970 forward rear derailleurs also have the mounting bolt threaded 26tpi of Campy.
I ruined the threads of another, foolishly changing between Shimano, Sachs-Huret, and Campagnolo
I wouldn't mind if a reply happens to mention whether more recently hanger bolts have universally standardized on 1.0mm thread pitch (25.4tpi), and whether there is any interchangeability of the 10mm bolts.
Harry Travis
Washington, DC
USA