The embodiment of the measure is usually a ball circulating screw. If the spindle is set in motion by the motor,
then the spherical thread nut, which works almost free of play, moves in longitudinal direction and pushes
the corresponding tool or work part carrier along the carrier track (see figure 7). The almost friction-free
transfer of power from the spindle to the carrier is achieved through a system of balls. To guarantee the
minimum of thread play the two halves of the ball thread nut are clamped against each other to achieve high
and reproducible accuracy of production. Eventual pitch errors of the spherical contour spindle can be automatically
rectified by the CNC control through the spindle pitch error compensation. Further mechanical possibilities
are for instance the rack/pinion and spindle/nut. If less accuracy is sufficient hydraulic drives are
used as well.