Mr. Jacques Perrier in Switzerland is one of largest parts-suppliers for Hermes and even Olympia typewriters.

He sells and ships parts around the world.  Usually he will want to see a photo or two of the machine or part you are needing.

I have been a customer several times.  He ships quickly and the part are always perfect.

He also runs a Typewriter Museum.

His contact email is :     musee@machineaecrire.ch

And a link about his Museum :    https://www.myvaud.ch/en/P6608/typewriter-museum

And a link to his site :     https://machineaecrire.ch/