With that sort of a speed my first thought is an induction motor.
Don't hang a rheostat on it unless You like smoke coming out of both
pieces. Change the pulley sizes with a belt or use a jack shaft and
4 pulleys and 2 belts. Carefully, a 4 pulley one will chuck you
across the room in pieces.
Get a gentler slower motor and make another new little one. A plywood
box (or even cardboard will last longer than you think. Shove an air
suction line blowing out the window and you are good to go. Any
questions just ask, I'm not that hard to find
Analog/Digital Modelling & Goldsmithing