G540 cutting size wrong

[Ed Williams]

I am having a problem. I have gecko servos on the rest of my mills so I thought I would try a stepper. On a unit that has the same ball screws that are on my other units. I am using the same code as on the others. I have my steps set to 10160 and the unit will move 49 inches. In mach it says 49 inches. But when I mill a piece it is always .015 smaller. It makes no difference if the piece is 1 inch or 5 inches it is .015 smaller. I have changed the spindle and collect still .015 smaller. Any idea.
Thanks Ed

[WoodSpinner]

I am having a problem. I have gecko servos on the rest of my mills so I thought I would try a stepper. On a unit that has the same ball screws that are on my other units. I am using the same code as on the others. I have my steps set to 10160 and the unit will move 49 inches. In mach it says 49 inches. But when I mill a piece it is always .015 smaller. It makes no difference if the piece is 1 inch or 5 inches it is .015 smaller. I have changed the spindle and collect still .015 smaller. Any idea.
Thanks Ed

repeatable backlash?