When the vertical turret decline, due to friction hinder its decline, the screw on helical screw nut under the physiognomy contact screw nut in the space below.

• 当垂直刀架下降时，由于摩擦力阻碍其下降，使丝杆的上螺旋面螺母的下螺旋面相接触，丝杆螺母的间隙在下面。