Another vote for James Poplin. The phone number is 1-706-678-5408. Get the 3M silica carbide belts for grinding steel. They are more expensive but last soo much longer. I use a lot of 60, 120, and 240 silica carbide belts from 3M, and the purple 400 grit from Klingspore. The klingspore is aluminum oxide I believe, silica carbide belts only go up to 240 grit. Hope it helps.
Tom