| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting tool which is formed such that machining of main chipping discharge grooves 4 and gullets 10 thereof is easily carried out. SOLUTION: According to the structure of a drill main body 1 of the cutting tool, if the gullets 10 are formed in each cutting edge 7, the cutting tool exerts a chipping partitioning function, i.e. a function of partitioning chippings during cutting of a workpiece to reduce cutting resistance, and therefore cutting efficiency is enhanced. Herein a cutting distance L of the gullet 10 that can exert the chipping partitioning function is set depending on the relationship between a diameter d of the drill main body 1, and a cutting distance M of the main chipping discharge groove 4 so as to satisfy the following formulae: 0.75d≤L≤4d, and 0.75d≤L≤0.25M. In this manner the cutting distance L of the gullet 10 is set shorter than the cutting distance M of the main chipping discharge groove 4, and therefore the gullet 10 can be machined after machining of the main chipping discharge groove 4, which facilitates machining of the main chipping discharge grooves 4 and the gullets 10. COPYRIGHT: (C)2009,JPO&INPIT
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