I did some adjusting to the bearings on the rails but they will still need to be changed. I was able to get to be useable but it definitely still has a problem. This is at 110 I.P.M., .005 Pixel Resolution, 25%, Horizontal, 3 height changes on Z, 24 in. X 24 in., on Poplar. I am going to do this again in 4 levels when I get new linear rail bearings. I sure am hoping that is what the problem was, I am almost sure it will do something.