John Chamorro

I come up with stone speed of about 200 rpm. The internet that's always right says a cyclist pedals about 100 rpm.

Hah! Yep I meant 22 inches,,,,,

Thanks for the reply. I'll fill in the blanks best I can not knowing the origins of the stone. I don't know how it was originally spun. It is 2 1/2" x 22' with a square wooden mandrel. When I got it, it was mounted in what looks like a high school welding project with sort of a tub, powered by an electric motor. It wobbled maybe an inch side to side and maybe 1/2" up and down. It was put together with pvc pipe and sealing foam with a chunk of all thread run through the middle, as the mandrel. I'm intending to plug and redrill the mandrel with a wooden dowel. Cosmetically and physically it looks to be in very good shape with only very minor edge dings in it. It's future use will be for sharpening hand made knives that my son in law makes as a hobby.

I'm rebuilding a sandstone grinder as a gift for my son in law. It's a cobble job that had a funky stand and the mandrel had pvc pipe and spray foam for alignment. I'm thinking I'll plug the wooden mandrel with a wood dowel and redrill it. I'm wondering what the rpm should be? Is it set by surface speed, or is there a recommended rpm x diameter depending on intended use? Any info or suggestions are welcome.