I put this together to cut aluminum. Chips get everywhere! Cover your lead screws. Put the mill inside an enclosure. DON'T mount electronics (especially the power supply) inside the enclosure, chips will get into it and short it out. Remove the manual jog wheels, they contribute to chatter (something about having a mass on the end of the lead screw causes vibration). I cut at 14000 RPM, 0.05 inch width of cut, 0.05 inch depth of cut, 30 inches per minute and just barely avoid chatter.