... Boring & Milling machine is of double-column beam gantry lifting structure and consists of such major ... machine bed, the workbench, the columns, the beam, the slide carriage box, the headstock, the ram ... sides and connected on top by the linkage beam, forming a closed gantry frame. The workbench ... small friction coefficient. Hydraulic balance is adopted for the headstock and the beam. Both the ram and ...