Workpiece adapter for use in a machine tool , comprising: an adapter base plate , a clamping attachment , by means of which the workpiece adapter can be connected to a clamping element in a rotationally and translationally fixed manner, a workpiece receptacle, and a workpiece-connection element , which comprises retaining means for detachably receiving a workpiece and connection means for connecting to the workpiece adapter , the clamping attachment being arranged on a side of the adapter base plate opposite the workpiece receptacle, and the clamping element being able to be mounted on a motor-operated spindle of the machine tool via a spindle receptacle , for machining the workpiece by moving and rotating the spindle , characterised in that at least three workpiece-attachment elements are arranged on one side of the adapter base plate in order to form the workpiece receptacle, by means of which a workpiece can be mounted on the workpiece adapter via the workpiece-connection element , the at least three workpiece-attachment elements projecting from the adapter base plate such that the workpiece-connection element is retained on the workpiece adapter at at least three points and is in a plane parallel to the adapter base plate , which is perpendicular to the rotational axis of the spindle . an adapter base plate , a clamping attachment , by means of which the workpiece adapter can be connected to a clamping element in a rotationally and translationally fixed manner, a workpiece receptacle, and a workpiece-connection element , which comprises retaining means for detachably receiving a workpiece and connection means for connecting to the workpiece adapter , the clamping attachment being arranged on a side of the adapter base plate opposite the workpiece receptacle, and the clamping element being able to be mounted on a motor-operated spindle of the machine tool via a spindle receptacle , for machining the workpiece by moving and rotating the spindle , characterised in that at least three workpiece-attachment elements are arranged on one side of the adapter base plate in order to form the workpiece receptacle, by means of which a workpiece can be mounted on the workpiece adapter via the workpiece-connection element , the at least three workpiece-attachment elements projecting from the adapter base plate such that the workpiece-connection element is retained on the workpiece adapter at at least three points and is in a plane parallel to the adapter base plate , which is perpendicular to the rotational axis of the spindle . the clamping attachment being arranged on a side of the adapter base plate opposite the workpiece receptacle, and the clamping element being able to be mounted on a motor-operated spindle of the machine tool via a spindle receptacle , for machining the workpiece by moving and rotating the spindle , characterised in that at least three workpiece-attachment elements are arranged on one side of the adapter base plate in order to form the workpiece receptacle, by means of which a workpiece can be mounted on the workpiece adapter via the workpiece-connection element , the at least three workpiece-attachment elements projecting from the adapter base plate such that the workpiece-connection element is retained on the workpiece adapter at at least three points and is in a plane parallel to the adapter base plate , which is perpendicular to the rotational axis of the spindle . <EOS>