Cruiser,

I don't have the gearset either. But I have another IH manual mill that still has the geardrive spindle if I need some extra grunt for some reason. I'm considering selling it though, because I very rarely use the manual mill.

Mactec54,
Two pulley sets sound interesting. It would be nice to be able to change out the pulleys and be able to achieve some higer spindle speeds. I only cut aluminum and plastic on my machine, so I could use the higher rpms sometimes. My only concern would be the spindle bearings. How much rpm can these bearings take? As my machine is now, I think my bearings are worn to the point that I need to replace them. I'm not able to cut aluminum with a 1/16" endmill without breakage no matter how slow my feedrate. But I can use an 1/8" endmill all day long without any problems. Spindle runout is definitely an issue. When running at higher rpms I can hear some noise from the bearings. I just haven't had the nerve to try and replace the bearings yet. I don't use the machine for production work, so its not that big of a deal right now.