Hi, I cheapskated it and bought a Chicago Electric/Drillmaster model 92623 sander/polisher tool for $39.99 from Harbor Freight, sort of similar to the one Herb Spitzer and others have used. It's speed varies from like 200 to 3777 rpm and it has a 5//8" x 11 TPI spindle. I have heard that the speed is not as constant on the very slow ones (no big deal for me I guess), and I have heard that it's best to break in the brushes by using on low-speed for a while, no problem.