I have the same question. I have a 1/4 electric motor, but I heard 1/2hp is preferred. I was told that you want a 1:2 ratio on the pulleys for a half HP motor. So if you have a 3in outside diameter pulley on the motor, you want a 6in dia pulley on the axle. I am trying to piece my own together right now.
The only question I have is that my 1/4 hp is rated at 1725 rpm. I cannot remember if the old forum said you want it spinning that high or not. I feel like I saw people on here saying you want about 450 RPM for a resurfacer. Hopefully someone smarter than me can chime in.