Abstract: The rotary cutting tool is used for making holes in walls of thermoplastic materials, e.g. fuel tanks produced by the blowing process. Cutting blades pointing roughly in the axial direction are placed on the free end face of a circular, rotary tool member and said cutting blade score and displace, instead of cutting the material. The cutting blades are arranged at a drawing angle to the axial direction and slope to the inside or outside, depending on whether a burr is or is not required on the opening edge. A holding device in the form of a mandrel or pin ensures that the cut out circular disk does not drop into the container. Thus, a cut is made, which is suitable for further processing by welding on connections or fitting seals and produces no chips and waste which could fall into the container.