As far as tolerance, i am hoping for at minimum .5mm across the 4ft span, but, .2 would be preferred. I have printed a jig that holds some work on an 18 deg angle, so i can rout out an edge at that angle. It needs to be fairly precise as there will be 20 pieces that have to fit just right to make a cylinder in the final work. How deep the cut is, how for it cuts in and the angle all have to be just right (at least +- .5mm on this cut) or the whole thing won’t fit together correctly. But, that is just one thing i am working on right now. Otherwise, overall i am so far very happy with the machine, and very thankful for your work.