I second the "as big as? you can find" suggestion.
I got one on ebay with the controller years ago for my mini-mill.? It's still just a mini-mill, but its a much better machine than how it started out.? I made a pair of 3 speed pulleys for it, but I never need to change it from the middle speed.? It has enough power to go whatever speed I want from the middle speed.? That's the big advantage of an overized DC motor.? You can achieve all the variable speed you need the dial instead of the belt.
