Why just use 1 motor? If you have an easy way to add a belt reduction, then do a 1:2 reduction, but still use both slaved motors.

Progress... I put a belt drive on each of the X and A axis to reduce the motor speed in half. I made sure there was no mechanical slippage by filing a flat on the shaft of the motor and ball screw shafts.
I ran a simple test pattern to put a 1/4 inch hole in the corners of a 10x10 square and I have 1/4 inch dowel pins for measurement. No matter how many times I run it, the A axis is ALWAYS .015 shorter
than the X axis. I retightened all the pulleys but to no avail. Then I switched the two axis wires on the Gecko G540 to see if was the driver. The same side was still short......
I have run out of ideas to try....Could the motor/motors be bad???
Any help would be greatly appreciated.