Ive been spending a fair amount of time improving my old Grizzly G0463 mill lately, and have been wondering about an improved spindle motor/control setup..

I currently run the stock motor, a claimed 3/4hp brushed DC motor, and replaced the crappy control with a Dorner DC controller (An Industrial conveyor control). This has proven much more reliable than the original control (I had replaced a few), but I do get spindle speed variation when entering "heavier" cuts.

What would be a good option for replacing the stock motor and drive? I've read a bit about a cheap servo motor and controller, I mainly want less (alot less) speed variation in cuts, and the ability to control speed through Mach3.