Drilling tool

Abstract

The present invention provides a tool for drilling, the tool comprising two or more cutting edges and a web thinning, in which a thinning heel surface facing backward in a rotating direction of the tool is formed by a convex surface, and in which a thinning angle gradually becomes smaller from a leading end of the tool toward a base end thereof. A thinning rake surface of the web thinning may be shaped straight so as to extend from an area around a center of the tool and in a radial direction or a parallel direction thereto in a tool front view. A thinning rake surface may be shaped in a helix in an opposite direction to the rotating direction of the tool so as to extend from an area around a center of the tool and in a radial direction in a tool front view.

Dependencies are inferred from the claim text.