A fuzzy model of the cutting process has been obtained for a vertical milling-machine, adopting a previously used technique [1]. The inputs are cutting speed, feed rate, depth of cut, tool diameter, and workpiece hardness, and the output is the result of the three-axis force sensor signal, working directly on the machine tool. The identification approach is a black-box type, where only a file of I/O data is necessary to construct the model. The fuzzy model consists of a number of IF…THEN rules with fuzzy antecedents and consequents. Five fuzzy models have been generated according to the material type used. The output error and the relative output error have been used as performance indices of the fuzzy models.