Patent ID: 7473059

Claim:
An end mill comprising: a shank having one end gripped by a spindle, the shank being rotatable about a predetermined rotation axis; and a blade body bonded to the other end of the shank, the blade body being rotatable together with the shank, wherein the blade body has a shape in which an area of a cross section in a plane perpendicular to the rotation axis decreases as distance from the shank increases, and wherein the blade body further includes: a flank-side surface including a flank and having a shape which is part of a curved surface of a circular cone, wherein a central axis of the circular cone and the rotation axis of the shank intersect each other, a rake-face-side surface including a rake face and adjoining the flank-side surface in two portions, the rake-face-side surface parallel to a central axis of the circular cone, a linear cutting edge parallel to the rotation axis at a certain distance from the rotation axis, the cutting edge formed in one of the two portions in which the flank-side surface and the rake-face-side surface come in contact with each other, and an end cutting edge adjoining the cutting edge in a longitudinal direction of the cutting edge, the end cutting edge formed at a right angle to the cutting edge, the end cutting edge disposed to be displaced from the rotation axis to one side; wherein the other end of the shank has an end face tilting to the rotation axis and an attachment hole formed perpendicularly to the end face, and the blade body is supported by one end of a tip, the other end of the tip being inserted in the attachment hole, the tip having a bonding surface bonded to an entire bottom surface of the blade body, the bonding surface including a bonding surface bonded to part of the rake-face-side surface of the blade body; wherein the attachment hole is a straight hole formed by perpendicularly sticking a tool in the end face after forming the end face tilting to the rotation axis; wherein the shank has a threaded hole formed perpendicularly to the attachment hole from a surface thereof; and wherein the tip is fixed in place by a screw screwed in the threaded hole.