can anyone point me in the right direction, what I want is to be able to control my spindle speed from using mach2 or 3, do i use a ac or dc motor. Then what do i need, is it a variable speed control board like the one on cnc4pc web site (i`ve got his breakout board) then do you need a vfd drive, or is that for ac motors only what do you need for a dc motor. i will be thankful for any help