| 摘要 |
A drilling and thread-milling tool is disclosed which has at its front-end 7 at least one end-cutting edge 8 for making a core-diameter hole and, behind it, non-pitched thread-milling teeth 4 to generate thread pitches and for which are provided an axial motion, rotation about its own axis as well as a helical motion. It is desirable that one tool should be adapted for making core-diameter holes of different diameters essentially by means of the end-cutting edge. This is accomplished in as much as the outer diameter of the end-cutting edge 8 is equal to or smaller than the minor diameter of the thread-milling teeth 4, in that the number of thread-milling teeth 4 arranged in axial succession is less than the number of thread pitches to be produced, in that provision is made for the simultaneous cutting of the core-diameter hole and thread pitches and in that the helical motion serving to generate the thread pitches consists of a number of orbits corresponding to the number of thread pitches to be generated. The drilling and thread-milling tool enables core-diameter holes of different diameters to be made with the same end-cutting edge because machining of the core-diameter hole is effected during the helical motion. |
