Abstract: The invention describes a method and a device for processing by chip-cutting of workpieces. It is preferentially applied for the cross-cutting and chamfering of extruded plastics material tubes. A chip-raising or cutting tool may be fed forward radially with respect to a rotational displacement of the workpiece in the direction of a center of relative rotation. An undulant approach motion is superimposed over the feed motion of the tool. The undulant approach motions of two directly consecutive revolutions are displaced in phase. As a result chip cuttings of uniform and predetermined length are produced with consequent facility in removal and avoidance of interference with the cutting operation.