Sec. to Prim. Pivot Point Distance -- For 5-Axis head/head machines, the center of the secondary axis may be offset from the primary axis. For example, for a CB machine, the B-axis center of rotation may be at a distance along the Y-axis. The signed distance is measured from the secondary to primary center. This distance is 0 if they are aligned. (Dblcom 1031 - 1033)