| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutoff elimination type machining rotary tool and a loose top thereof.SOLUTION: This loose top for a rotatable loose top tool includes a front end and a rear end, a center shaft extending between them, and a centering pin similarly projecting backward in the axial direction from the loose top. The centering pin includes two surfaces (29, 30) opposite to each other in the radial direction, and the first one thereof is formed with a contact surface (29) extending in the tangent direction between two boundary buses (31a, 31b) extending in the axial direction, and the boundary buses are positioned along an imaginal outside circle (S1), and the center of the circle coincides with the center shaft (C), and an arc angle (α) between them is smaller than 180°, and the contact surface changes from the outside circle (S1) to the second surface with an interval through the boundary buses (31a, 31b). |
