The invention relates to a machining device (5) comprising a workpiece (8) and at least one machining tool (23, 40, 41) and a measuring device (1, 22) and a seat (20) for the workpiece (8) to be machined. The workpiece (8) has a reference surface (26, 32, 33) that is disposed on the workpiece (8) and interacts with the machining device (5) in such a manner that a contour can be produced on this reference surface (26, 32, 33) using the machining tool (23, 40, 41) and that the contour (34, 35, 50) can be detected by the measuring device (1, 22) after machining. The method for controlling a machining device (5) comprises the following steps: introducing a contour (34, 35, 50) into the workpiece (8) to be machined in the longitudinal direction of advance of the machining tool (23, 40, 41); measuring the contour (34, 35, 50) in the workpiece (8) produced by machining; adjusting the machining plan while taking into consideration the determined tool geometry.