The only problem with mine was the belt would slip to much. So in my quest for more power and torque I'd did the unthinkable.
I made a chain drive mill!
You wouldnt believe how close a set of mountain bike sprockets were to the diameter of the original pulleys.
I even made a little chain tensioner for it.
The only problem is that I ripped off a cheap clamp I had on it. The bit stuck in the material and broke the bolts right off the clamp. I had it mounted with dinky little bolts anyway. The new one is mounted with 1/4" bolts. Now the problem is I need a beefier X/Y table. I can see it just slightly twisting when I really get down on it...
Now I just wish I could find a decent thread cutting machine. I'm getting some HUGE arms from tapping 3/4"x16 threaded holes in copper. Right now I've got an old drill press with no motor on it and a big "T" handle on the top of the spindle. I just clamp the block down and start cranking...