BVTC series is the vertical lathe with double columns and determinate beam which is specially processed and developed for tyre mould, slewing bearing, tube-sheet of heat-exchanger, steamer impeller, and disc-type parts like flange plate. When processing the straight line, we can also process taper continuously without stopping the lathe and adjusting the knife rest, and any complex curve like circular arc. It is controlled by half closed-loop servo, the principal axis adopts stepless speed control of frequency conversion. An encoder is added onto the principal axis, which can cut thread, and cut with constant linear speed. Since determinate beam is adopted, the whole facade forms a steady and firm planer frame to ensure the complete stiffness of the machine tool, which has better cutting stability and precision than the common movable beam lathe.