If you just want rapid (rough) positioning What you can do is fit a DC servo motor, there is always plenty on ebay and also pick up a PWM drive like AMC or Copley, again cheap on ebay, and set up a pot for speed and direction and disable the drive when you don't need it, you do not need an encoder for this, just a motor with a tach.
If you use this method for cutting then you will have to visually monitor the feed as the tach will compensate to some degree, but heavy cuts will tend to slow the feed.
Al
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.