You mention it got off track near the end when it reversed direction. Did you set the stepper motor potentiometers? X-Carve Maintenance/Troubleshooting Videos - Add Your Own! - #3 by RobertA_Rieke This thread has a lot of good information. Watch the video on stepper motor potentiometer setting. When it reversed directions (guessing it went from clockwise to counter clockwise?) it may have switched from conventional milling to climb milling which is a little bit tougher on the machine. If your motors are not receiving enough current to move it then it could have lost steps and would have no longer been following the pattern.