I have a nice set of 8 rings. I don't know who made them. The routine that I am looking at calls for an extra ring, making a total of 9. Does anyone know where I can buy a single ring?

Not without knowing the exact make of the rings you already have.

You would have to know the metal used, (aluminum, steel, hollow or solid) what kind of finish (nickle, chrome, polished steel,...)

Having someone make an extra ring to match would probably cost more than just buying two new sets.

What routine are you looking at? Do they give suggestions? I'm guessing the creator simply had some spare sets laying around and took advantage of what was available.

My set is a Mak 8", and the routine comes from Edward Victor's 'More Magic of the Hands." What I like about it is that the gimmick isn't slipped in until near the very end of the routine after all of the rings have been ofviously handled by the 2 assistants.

Slydini had the rings examined and set them down over a handkerchief, picked handkerchief up thru the rings to wipe his hands. Then picked 'em back up (adding the important ring).