| 摘要 |
PROBLEM TO BE SOLVED: To correct a lead and a helical angle of a helical groove of a workpiece to a predetermined range without causing the cost increase by generating a large error in the lead and the helical angle. SOLUTION: A cutting blade 5 at the tip end side of a broach body among the blade edges spirally arranged on the outer peripheral part of the broach body is made to be a roughing blade, and the cutting blade 5 at the rear end side of the broach body is made to be a finishing blade 7. In the finishing blade 7, a cutting blade 9 is formed on an intersection ridge line part of a rake face 7A toward the tip end side of the broach body and side surface 7B toward either one side of peripheral directions of the broach body, the intersection ridge line part of the side surface of the opposite side to the cutting blade 9 and the rake face 7A is made to be a guide blade 10, the side continued to the guide blade 10 is made to be the guide surface 7C, the portion composed of the guide surface 7C and the guide blade 10 is made to be a guide part 11, and the guide part 11 is arranged so as to be a lead different from the lead of the roughing blade. COPYRIGHT: (C)2008,JPO&INPIT
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