Just want to say how brilliant Linux CNC is! I have CNC'd my X2 mill and it has been well worth while. The painful X2 Z axis is now perfect with a ballscrew. X and Y are still with the original screws but I get excellent results. I have added an A axis interlinked with the spindle so I easily Hobbed a 72 tooth worm wheel. Currently making a stepper driven rotary table, CNC is great for hacking out the space for the wheel and bearings. All this and its "FREE", I highly recommend it!
Also CAMBAM to generate the Gcode.