| 摘要 |
PURPOSE: To provide a cutting tool capable of elongating its life without lowering the roughness of a finished face, to be used in the finish turning with a depth of the cutting within a circular arc-shaped cutting blade of a nose. CONSTITUTION: In this cutting tool having a chamfering 5 along the circular arc-shaped cutting blade 3 of the nose 2, a chamfering width of the circular arc-shaped cutting blade observed from a cutting face 7 side is gradually widened from the neighborhood of each contact point P1 of the circular arc- shaped cutting blade 3 with each of two straight cutting blades through the nose 2, toward an approximately intermediate point Q of a circular arc of the circular arc-shaped cutting blade. Whereby the cutting can be executed in a state that the circular arc-shaped cutting blade part of a small chamfering width is positioned at a front clearance boundary side and the circular arc- shaped cutting blade part of a large chamfering width is positioned at a lateral clearance boundary side. |
