Strange problem. I am using Mach 4 on a win 7;computer running gcode produced in Fusion 360.
I noticed that I was a mm or two out of calibration, so I decided to recalculate all three axis. X went great, but I had to change units from 33.something to 60.something on the y axis. Seemed weird sinse it was only out by 1.5mm or so, but I made the change and when I measured the y movement, it was spot on. I did a test run (75mm circle inside a 100mm square).and x was ok, but y was almost twice what it should be. I checked the calibration again and it still moved exactly 200 mm for the y 200 command. The tool path appears normal in the preview window.
Is there some setting somewhere that would cause the units to be off by that much during a job even though calibration seems fine?