| 摘要 |
PROBLEM TO BE SOLVED: To provide an ultrashort bit that is excellent in durability, capable of preventing vibration, and suitable for an angle-type rotary tool.SOLUTION: The ultrashort bit 10 comprises: a tip 12; a shank 18 fitted into a socket part of a rotary tool and subjected to a turning force from the rotary tool; a torsion part 16 that is narrower than diameters of the other regions, to which a locking member of the socket part of the rotary tool is fitted; and a circular cross section region 14 having a circular cross section shape coming into internal contact with the cross section shape of the shank 18. The torsion part 16 is twisted when being subjected to an overload to prevent the tip 12 from being broken. The circular cross section region 14 of the ultrashort bit 10, which is fitted into the socket part, abuts on an inner surface of a hexagonal hole of the socket part to suppress vibration. |
