Hi Guys, I have a question if anyone could point me in the right direction.

Example:

If I design a 30mm pocket in bobcad and go out on my mach 3 machine and cut it it will be about .15mm smaller than 30mm. I though maybe it was backlash so I went through and checked and tested etc.... and that was not the issue. Finally someone told me to use the circle wizard in mach3 and if that works it is something in the cad/cam. So I did a circle 30mm in mach3 circle wizard and it was perfect. So I guess this means the machine is correct, but what would it be in Bobcad, maybe a setting I am missing?

Thanks so much guys