| 摘要 |
PURPOSE:To uniformly use both side blades of a cutter so as to prevent the cutter from wear, by providing such a method that cutting is made along one of wall surfaces of a thread initially, then along the other wall surface secondly and along the above-mentioned one wall surface thirdly, and these steps are successively and repeatedly carried out for both wall surfaces. CONSTITUTION:A workpiece 2 is cut by a constant cutting depth so as to form a thread having a thread height K. Firstly, as indicated by I, cutting is made along one of walls of a crest of the thread by a cutting depth (d). Secondly, cutting is made as indicated by II by the identical cutting depth (d). Thirdly, by cutting is made as indicated by III by a cutting depth (2d) along the one wall surface. Further, as indicated by IV, cutting is made along the other wall surface by the identical cutting depth (2d). The above-mentioned steps are successively repeated so as to out both wall surface, alternately, and when the thread- height becomes more than K at the final cutting, the thread is cut down so as to have the thread-height K, thus completing the thread cutting.
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