| 摘要 |
An extremely practical rotary cutting tool in which chips can be excellently discharged even in longitudinal machining. A large number of helical chip discharge grooves (2) are provided in the outer periphery of the forward end of a substantially circular columnar tool body (1), and a bottom blade is provided at each ridge line where a rake surface (3) of a chip discharge groove (2) and a tip clearance surface of the tool body (1) meet. That portion of at least one bottom blade which is close to the outer periphery of the tool is immersed in the axial direction of the tool body (1) to form a non-cut portion (22). |
