| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting tap capable of reducing surface roughness of a flank of a female screw formed on a workpiece.SOLUTION: A cutting tap 10 is a spiral tap. Because chips generated during cutting processing are discharged toward a rear end side in a shaft center direction of a tool body, the cutting tap 10 is pushed to a progress direction side easily by reaction force of the chip discharge. On the other hand, respective reeds of screw threads of a chamfer part 21 are corrected so as to become smaller than reeds of screw threads of a perfect mountain part 22. Therefore, correction amounts of the reeds of screw threads of the chamfer part 21 and a dimension in which the cutting tap 100 is pushed to the progress direction by the reaction force of the chip discharge are cancelled by each other. As a result, the formation of irregularities on a flank of the screw thread of the female screw can be avoided to reduce surface roughness of the flank of the screw thread. |
