End mill

Abstract

This end mill comprises a peripheral cutting edge along a helical flute, and a bottom cutting edge. The helical flute comprises a first flute (21) and a second flute (22). A flute bottom of the first flute (21) comprises a straight portion (41), a radiused portion (42), and an inclined portion (43). The straight portion (41) extends linearly in parallel with an axis O from the tip of the tool toward the rear end side to a position distanced by the length of an outer diameter of the tool. The inclined portion (43) is provided on the rear end side of the straight portion (41), and is linearly inclined radially outward from the straight portion (41) side toward the rear end side. The radiused portion (42) connects a rear end of the straight portion (41) and a front end of the inclined portion (43), and curves radially outward arcuately from the straight portion (41) side toward the inclined portion (43) side. The rake angles of the peripheral cutting edge and the bottom cutting edge are constant over the entire circumference.

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