Hello All

I have just finished my second machine and have ran into an unexpected problem. My machine will not hold size properly. What I mean is this...

When I set the "steps per", in mach3, to cut a 1" slot to the correct length and then cut a 6" long slot it is off by .03" or so. If I then set it to cut the 6" slot correctly it then cuts the 1" slot wrong. The backlash is good and I programmed the "slop" out by feeding to position before cutting into the part. I get the same result in both X and Y axis. It also happens when cutting circles, squares or any other figure. It's almost like it is scaling or something but the scale is set at 1.0 in mach3. This is a stepper machine with rack and spur gear, Mach3, gecko drives. Any suggestions on what my problem could be?

Thanks
Allen