| 摘要 |
PROBLEM TO BE SOLVED: To provide a head replacement type drill which has a stable process tolerance.SOLUTION: A head replacement type drill equipped with a drill body which advances in an axial direction while rotating, a pair of opposite pieces which are formed at a front end part of the drill body, and a head which is detachably attached between the pair of opposite pieces in which the drill body has a bearing surface which supports the head from the posterior in the axial direction, the bearing surface is so formed as to connect the pair of opposite pieces without segmentation between the pair of opposite pieces, at least one of the pair of opposite pieces has a torque transmission surface which supports the posterior surface of the head in a rotation direction, and an inner diameter end of the torque transmission surface is formed on a rotation direction front side with respect to a straight line connecting a drill center and an outer diameter end of the torque transmission surface to each other.SELECTED DRAWING: Figure 5 |
