Problem- Calibration or gcode error?

[Lappy]

Hi All,
sorry if i have posted in the wrong area
Just having an issue with either the calibration or gcode,

Basically went through the calibration setup of each axis and tested it by inputing code into the directly into the MDI window and cutting a 150 by 150 box with a 6.35mm cutter. from this the calibration appeared correct. (-/+ .05)

Next i tried to cut a 150mm box with gcode from mastercam:

N720 Z6.
N730 G01 Z0.
N740 X146.825
N750 Y146.825
N760 X3.175
N770 Y3.175
N780 G00 Z26"

but after i measured it it was out by .65 on the y axis and .5 on the x axis, which seems strange it would be out as clearly the above code says both X&Y are the same?! hence why i'm not sure if this is a MC issue or M3?

Any thoughts or advice would be greatly appreciated!
Cheers
Lappy

[ger21]

From what you show, it should cut the same in X or Y. You may need to fine tune your steps per inch. Feedrates can also effect size errors, especially on less than rigid machines. Backlash can also cause this.