I have a gantry with gecko 320 drives and Mach 3. I can calibrate with a micrometer to get exact 50 thou repeat movements on x and y. The movement is over traveled then at long distance,like almost 2 inches on a 48 inch move. If I calibrate for the long distance move then the short distance is off. It is mostly used for wood so being exact is not critical, but I cannot get a round circle. 20 to 30 thou off on a 2" circle. Any advice on how to analyze this appreciated.