At Marcia's suggestion, have tried using my bench grinder with a 600 grit wheel. It works very well. The cut is very smooth and slow enough that you feel like you have good control but fast enough to get the job done quickly.
though I have not gotten beyond using iron oxide and a drafting to write a number on the bottom of my pots and steel art, I'm looking for some way to put the URL of a web gallery on them. My theory is that until I become a world-famous artist, which of course will only happen after I'm dead, the most important information is how others can get back to me if they see some of my work that they like. I am trying to find some kind of stamp or stencil that I can use to put that information on my junk.
Actually, a drafting pen with iron oxide works quite well if you just want scribble something on the bottom of the pot.