I recomend you buy a mill that is already CNC and has a bad controller. Often CNC mills have auto lubrication systems so the iron is often good while the controller is dead.
A Bridgeport Series I is a great candidate for a retrofit. Steppers, ballscrews are already there. Mine sits in my garage with her car on one side and my truck on the other.

It took me one week working evenings and weekends to convert this old
BOSS 4 to a PC retrofit. I used Gecko driver boards, a WIN 98 Compaq laptop and Turbocnc. Had it four years now and I just love the thing. $2500 invested
A few people said the laptop would not hold up and neither would the Gecko drivers. I have had no problems with the laptop or the Gecko drivers. Only problem I had was the spindle belt broke. Probably 35 years old.
Outback
Last edited by outback; 02-08-2010 at 10:29 PM.
So much to learn, so little time