Abstract: An end mill body wiih a corner cutting edge forming a convex arc shape of which the rotation locus becomes convex toward the tip outer peripheral side is formed at a side ridge portion of the corner cutting edge rake face, a gash is formed on the inner peripheral side of the corner cutting edge rake face, and an end cutting edge connected to the corner cutting edge and extending toward the inner peripheral side is formed at a tip-side side ridge portion of the end cutting edge rake face. An intersection line between the corner cutting edge rake face and the end cutting edge rake face is located closer to the radial inner peripheral side with respect to the axis than the center of the convex arc that the corner cutting edge forms in the rotation locus.

Abstract: Damage to a corner cutting edge or degradation of the roughness of a surface of workpiece caused by changes in the cutting edge strength of the corner cutting edge or variations of cutting load is prevented.

Abstract: A plurality of chip discharge flutes are located on an outer periphery of a tip portion of the end mill body which rotates on its axis. Helix angles between the axis and the cutting edges in the chip discharge flutes, of which are at least one or more; are different from others. A cross-section perpendicular to the axis shows that a flute bottom face in a main flute portion forms a concavely curved shape from the rake face to a point where the flute bottom face, touches a web thickness circle of the end mill body, forms a linear shape, and goes toward the end mill rotating direction; and a flute bottom face in a sub-flute portion forms a linear shape, intersects with the flute bottom face in the main flute portion at an obtuse angle, goes further toward the end mill rotating direction.

Abstract: A plurality of chip discharge flutes are located on an outer periphery of a tip portion of the end mill body which rotates on its axis. Helix angles between the axis and the cutting edges in the chip discharge flutes, of which are at least one or more; are different from others. A cross-section perpendicular to the axis shows that a flute bottom face in a main flute portion forms a concavely curved shape from the rake face to a point where the flute bottom face, touches a web thickness circle of the end mill body, forms a linear shape, and goes toward the end mill rotating direction; and a flute bottom face in a sub-flute portion forms a linear shape, intersects with the flute bottom face in the main flute portion at an obtuse angle, goes further toward the end mill rotating direction.

Abstract: The present invention provides a member coated with a hard coating and to attain excellent wear resistance. The hard coating includes: an adhesion reinforcing layer formed on a surface of the member; and a second layer formed on the adhesion reinforcing layer and having a composition represented by the following formula: (AlpTiqVr)(NuCv) where 0≦p≦0.75, 0.20≦q≦0.75, 0.10≦r≦0.75, p+q+r=1, 0.6≦u≦1, and u+v=1. In order to further enhance the adhesion of the hard coating to the member, an intermediate layer may be formed between the first and second layers.