| 摘要 |
PROBLEM TO BE SOLVED: To provide a bit which is equipped with a flat plate-shaped torsion part, and has excellent durability and a good balance.SOLUTION: A bit 10 comprises a tip 12 (working region), a shank 18 (torque transmission region) which is fitted into a socket part of a rotary tool and received a turning force from the rotary tool, an engagement groove 16 into which an engagement member of the socket part in the rotary tool is fitted, and a flat plate-shaped torsion part 14 (shock cushioning region) which is provided between the tip 12 and the shank 18. The ratio of the cross section of the torsion part 14 to the cross section of the shank 18 is 1/2 or more and 32/35 or less, or the ratio of the thickness (t) of the torsion part 14 to the width (W) thereof is 1/2 or more and 3/4 or less. |
