Thanks for all the input. It will look like a typical engineering iron ring:
(image from wikipedia)
I could make the band on a lathe, but I don’t think I could get the outside texture right after that.
@Big_Mak I hadn’t heard from Shapeways before, that’s handy to know about, although I’m going to avoid using 3D printing for this project. That ring looks great!
@hectorh that electric arc furnace is sweet. If I can’t find access to a furnace through ucb or other I might have to take a stab at making that…