Method and device for determining a machining axis

In order to determine the machining axis of a rotatable workpiece blank, a reference workpiece, which has bearing surfaces concentric to its imbalance reference axis, and subsequently a workpiece blank are received in a measurement device, and as yet unmachined surface regions of the reference workpiece and of the workpiece blank are measured by a sensor device, and the measured position data are stored by a computer as a reference partial surface and a blank partial surface in a data storage device. The computer calculates deviations between the blank partial surface and the reference partial surface and, from these, an imbalance effect which is expressed by the position of the main axis of inertia of a given workpiece. The machining axis is calculated by adding an offset to the position of the main axis of inertia, which offset has been empirically determined with the aid of the actual imbalances of previously produced workpieces measured relative to the machining axis.