Quote Originally Posted by RichardR View Post
I don't know what I did but I got it all moving on the manual jog , then realised that it was a negative movement, so all working, I checked the amount it moved after my G code input and it was within a 0.??mmm I guess that due to the pitch on the screw thread it is as near as possible, or should I change to inches and try that?
You can work in mm or inches by using G21 or G20 at the top of the gcode.

How near is 0.??mm. Now you have it running cut a square out and measure the square with a vernier
Also you can measure the diagonals to see if the gantry is out of square.

Edit: Joking aside you have coma a long way from spitting the dummy out.