All Machines are Precision machined to high tolerances in Aircraft Aluminum Profile railing for Maximum strength and accuracy High precision Ballscrews on all axis for best accuracy           Every mating surface is machined completely flat NO need to square machine. Every part is pocketed , pined  or has ledge to sit on leaving machine square without  need of any gauges Check XZ forums for extra info 24 or 30 inch wide All in 3/4 inch Aluminum 20mm Profile rails 16mm and 20mm Ballscrews 40 wide All one inch Aluminum 25mm rails All 25mm Ballscrews                    56 inch wide             All one inch aluminum          25mm rails and Ballscrews