| 摘要 |
PROBLEM TO BE SOLVED: To finish-cut the end surface of a flat part in an inner diameter grooved pipe by using a flat part length setting jig set to a prescribed size, at the time of cutting off the inner diameter grooved pipe with the flat part. SOLUTION: On a plate-like material surface, the material having a length constituted with the flat part A having the length of a necessary size LA + excess size for cuttingαand a part for arranging the projecting and recessing grooves 2 of a necessary size LM by plastic working and the flat part B arranging a necessary size LB + excess size for cuttingβ, is repeatedly formed. Boundary parts 4, 5 with the flat parts A and B are cut off to obtain the grooved pipe with rough flat part. At this time, the flat part length setting jig 6 is used to calculate a cutting-off position. This size setting jig 6 is intergrally constituted with a fitting part 7 fitted to the inner surface of end part of the flat part A (B) and the rear end flange 8, and a length between the front end surface 7' of the fitting part 7 and the rear end surface 8' of the flange 8 is set to a fixed size LC. The jig 6 is fitted to the flat part A (B) and the cutting length is set.
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