| 摘要 |
PROBLEM TO BE SOLVED: To provide an insertion type small-diameter rotating cutting tool designed to improve tool rigidity. SOLUTION: The small-diameter rotating cutting tool 1 comprises a tool body part 2a formed of a tool body material made of cemented carbide and a shank part 3 formed of stainless, steel or the like. The two parts 2a, 3a are joined together by a shrinkage fit, brazing or press-in method, or by an adhesive. By connecting the tool body part 2a to an intermediate reinforcing part 2b and an insertion part 2c, reduction of diameter is effected in three steps. The diameter of the intermediate reinforcing part 2b is set to at least twice as large as the diameter of a blade tip during formation of the tool from a point of view of rigidity and set to up to 98% of the diameter of the insertion part 2c from a point of view of finishing precision. A length L of the tool body part 2a is set to 30-70% of a protrusion length L2 containing an intermediate reinforcing part 2b.
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