Abstract: The present invention relates to coordinate measuring machines which are used for determining the location of a point in the X, Y and Z axes in order to permit inspection, checking, or performing other operations on work pieces. The measuring machine includes a probe for engaging the work piece and providing position information of points on the work piece. The probe is mounted on a cantilever arm that is supported on two parallel dual granite ways or rails through air film bearings. The probe is counterbalanced in a unique manner with an air cylinder and is also mounted on air bearings on its cantilevered support arm, and the probe may be rotated 360.degree. for maximum flexibility and ease of operation.