Hi Folks
J.Agnew has an Italian bike with a pivot bolt for Juy52 on it.
I have handled a Juy52.It is the Made in Italy version of Juy51.Possibly the threaded parts are different,but that would be all.A Juy51,which comes available periodically, would be a fine installation.The pivot bolt would probably do just fine for an old TdF(Tour de France)Simplex anyway.
The twinned levers with a Juy53 is already super rare and kool,especially on Italian,so I'd say it's worth the effort to keep Simplex on the bike.
Seth Finkelstein,Santa Cruz,CA