Just got my Desktop last week and started out by cutting some modeling parts out of 1/4" aircraft grade plywood (Midwest brand). The issue I'm having is if I, for example, cut a 3.000" diameter circle it measures about 10 thousandths over once cut. I tried adding an extra final pass and this hasn't seemed to have any effect. Is there a "springiness" issue with wood or am I expecting too much from the machine?

I've tried it with multiple bits, both 1/8" and 1/4", and there is no difference. I'm thinking of setting the bit diameter 20 thousandths smaller but before I do that I thought I'd ask here to see if you guys have any ideas.

Thanks,
Randy