This just means that there is some error in your calibration or your machine is
flexing during cuts.
first make sure that the motor mounts, top beam, and brackets holding the top
beam are not flexing during cuts (recording video from a tripod zoomed in on
the motors will show even small movements easily)
in terms of your calibration, accurate measurements are a must. see the
side-discussion about class 1, class 2 and unrated tape measures in the topic at
also you may be interested in lookup up the topic “sources of error” (sorry, my
browser is misbehaving, so I can’t pull up the link at the moment)
you don’t say if you are using standard triangular calibration or the new holey
calibration that’s available in webcontrol
for the distance between the motors, did you measure it with a tape measure? or
did you use the chain measurement? if you have an accurate tape measure, it’s
best to measure this as the chain isn’t exactly 6.35mm per link.
David Lang