I seem to be gaining steps over the project.  I started a mock (Safe Z position, spindle not running) surfacing for a 24x24 square.  I used a fine pointed bit to mark my home at x=20.125 y=12.5.  I started the run and let it make all 17 rounds.  When it finished and returned to home I was at x=13.75 Y=6.375, a change of -6.375 in my X-Axis and -6.125 in my Y Axis.

I have done "Set steps per units" and tuned both axis to over 12", 24" and 36" travels in both positive and negative directions.  I'm using my laser tape to take the human error out.  I've even sat and ran it on both axis positive and negative a dozen times in a single setup and cannot reproduce the problem.

I generated my GCode from Cut2D Desktop.  A simple 24x24 square, pocket toolpath, post processor "G-Code (Inch) (*.tap)"  Ran the Code in Mach3 Version R3.043.062.

I'm at a loss with this problem.  Any help is greatly appreciated.  If this needs to be somewhere else (different group, forum, program) please let me know.

pls post your G-code

attached.

your G-Code is running with F100.0.
try to run it for a test with F10.0

what are your settings in motortuning for the X and Y axis?