| 摘要 |
In the radius end mill, main gash faces has an angle of inclination with respect to an axis that is smaller than a twist angle of chip discharge flutes. The main gash faces are formed on inner circumferential sides of distal end portions of wall surfaces that face in a tool rotation direction of helically twisted chip discharge flutes, which is formed on an outer circumference of a distal end portion of a tool body that is rotated around the axis. End cutting edges are formed on a distal end of the main gash faces. Sub gash faces has an angle of inclination with respect to the axis that is greater than that of the main gash faces. The sub gash faces are formed on an outer circumferential side of the main gash faces such that they extend away via step portions from the main gash faces. In addition, corner cutting edges that have a protruding arc-shaped contour are formed to be continuous with an outer circumferential side of the end cutting edges extending from a distal end as far as an outer circumference of the sub gash faces.
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