Residual stress occurs in many machined components and parts and they cause the corrosion or destruction of components. The paper deals with evaluating residual stresses during an irregular interrupted cut with the use a ceramic cutting tool. Tests were performed on the conventional lathe with using a simulator of interrupted cut called “slats test”. The regular or irregular interrupted cutting process was simulated with a different number of clamped slats in the simulator. Machined slats were made from two kind of material, steel C45 and 14MoV6-3. For evaluation of residual stress there was selected the non-destructive method based on the principle of X-ray diffraction. The results were measured by the device Proto iXRD Manufacturing. The experiment was done in cooperation with the University of Zilina in Zilina, Slovakia.