... valve seats ring. Adopted rectangular guideway with high rigidity. Machine head can be moved up and down automatically, easy adjustment ... operation. Equipped a guide shaft with corresponding size, the machine can repair the valve seats ring with diameter 20- ... specificationsModel T8590AT8590BBoring diameter20-90 mm20-90 mmSpindle speed range55, 85, 210, 320, 370, 550 rpm30-550 rpm (Stepless)Spindle ...