A rotary tool (21) working surface (23) includes a plurality of cutting bodies (24). The rotary tool (21) can be driven about a rotational axis (R). The actual enveloping surface (HF) of the working surface (23) is ascertained by an optical measuring arrangement (29). At least one other target variable (GS) is detected, which describes a microscopic parameter of the working surface (23). The actual variable (GI) corresponding to each specified target variable (GS) is detected by the measuring arrangement (29), and the deviation between the target variable (GS) and the actual variable (GI) is determined. If the actual enveloping surface (HF) lies outside of a specified target enveloping area (HR) or if a deviation (D) between an actual variable (GI) and the corresponding target variable (GS) is unacceptably large, selected first and/or second cutting bodies (24a, 24b) are machined and/or removed by a laser device (35).