A control device for tools arranged to apply fasteners in a production process is provided. The control device is configured to, in a production configuration process: obtain a set of trace data for a plurality of test fastening application operations performed by the tools, from said set of trace data, derive maximum and minimum values (T.sub.max, T.sub.min) indicative of application force, or a derivative thereof, for each one of a plurality of values indicative of displacement or time (), and calculate a first and second polynomials based thereon; based on the first and second polynomials, set upper and lower limit curves. In the production process, the control device determines that a fastener application operation is not okay (NOK) if its' trace data goes beyond the upper and lower limit curves. Hereby, a balanced trade-off between the generosity/strictness of the limits is provided to improve accuracy of NOK operation detection.