This paper, following the present intention of research engineers to take advantage of the hardware capabilities of modern CNC systems, proposes a real-time interpolator for machining the specified type of pockets which overrides the disadvantages of the existing approaches. The proposed real-time interpolator generates successive offsets (pocket contouring) of the original boundary with the highest possible accuracy, of which the milling machine is capable. Machining accuracy is obtained by applying the locus tracing concept [7], for driving the tool along the offset of the epitrochoid. The concept is generally applicable in motion generation [8–10]. In this paper, its application is illustrated in the context of motion generation along the offset of the epitrochoid. Instead of using an exact analytic expression or a piecewise-analytic approximation for the offset, the method uses analytic concepts and the defining geometric property to generate a succession of points on the locus (the offset of the epitrochoid), through repeated application of two analytically implemented construction operations. These operations are designed to achieve coordinate increment step control, automatic error control and maximum advance along the local tangent. Finally, the method is characterized by its simplicity since the whole machining task can be programmed in a single block of the part program. Similarly, with the programming of a circular or a rectangular pocket, the user specifies in one block the geometric form of the boundary curve (epitrochoid), the tool radius, the plunging depth, the total depth and the allowances for the wall and floor finishing.