Abstract: A geometrical error measurement method for a feed drive system includes entering coordinate values of four vertices of a virtual regular tetrahedron, mounting a position indicator to an end of a main shaft of a feed drive system, mounting three center mounts at three respective vertices of the four vertices except for the remaining vertex at which the main shaft is positioned while moving the main shaft of the feed drive system sequentially from one vertex to another according to the entered coordinate values, measuring distances between each of the four vertices indicated by the three center mounts and the position indicator with a double ballbar, and calculating a geometrical error from the measured distances.

Abstract: A geometrical error measurement method for a feed drive system includes entering coordinate values of four vertices of a virtual regular tetrahedron, mounting a position indicator to an end of a main shaft of a feed drive system, mounting three center mounts at three respective vertices of the four vertices except for the remaining vertex at which the main shaft is positioned while moving the main shaft of the feed drive system sequentially from one vertex to another according to the entered coordinate values, measuring distances between each of the four vertices indicated by the three center mounts and the position indicator with a double ballbar, and calculating a geometrical error from the measured distances.