High strength casting, high stiffness, high precision and long life. The guide rail and work table surface are quenched, tempered and hardened, and are ground. The guide rail is bonded with high wear-resisting Turcite-B plate. The enhanced Z-axis, X-direction dovetail guide and Y-direction square guide have stronger bearing capacity and higher accuracy. GM-4S Milling machine High precision and durable spindle.The axial runout of spindle pin gap is controlled at 0.002mm-0.005mm. high cycle hardening treatment of spindle tube surface, hard coating, precision grinding, spindle and housing. The bed column adopts double-layer reinforcement structure to ensure the high rigidity and no deformation of the Milling machine.