US Patent 11623286 Tapered end mill

A tapered end mill includes an outer circumferential cutting edge, a flute is disposed such that a flute bottom radius defined as a distance between a flute bottom and the tool axis decreases from a shank side toward the tool tip side, the flute bottom radius linearly changes at a predetermined gradient angle in the tool axis direction, the gradient angle changes at a predetermined change point to become smaller on the tool tip side as compared to the shank side, and a gradient angle θ