Last month I had a problem with my Z Axis. It just quit working after two hours of a 3D cutout (about 3/4's done). At first I thought the driver had gone away, but that was not the case. After cycling power and restarting it seemed to work fine again, so I started cutting again on the opposite side of the mahogany board. It quit again at about 1 1/2 hours. So I started looking for mechanical reasons for going into left field. Didn't take long to see the wear marks on the Z Axis steel. I took it apart, cleaned it up and checked the pinion also. It looked new. I got a quote from Jeremy for a replacement Z and knew my wife wouldn't go for that, so I found my solution in a flat file, bench vise, and some elbow grease. I smoothed out the bumps pretty well and put it back together. Good luck there! I had to drill four 3/4" holes in the steel mounting tubes where the upper adjustable wheels mount so I could tighten the mounting nuts. Two of them were loose when I took it apart and probably were like that when I got it. I had never had a reason to adjust them until now. They were moving with the Z axis motion. I also had to fashion a spring catcher (ground a hacksaw blade near the mounting hole and reaching this up the tube, snagged the spring and pulled it down to mount to the lower attachment point). After rebuilding this, I really envy anyone with the new PRS Z. I think I remember someone doing this on the forum many years ago, but I could not find it again.