Boring tool and method of boring pilot hole

Abstract

A boring tool can form a hole accurately by improving the rigidity of a reamer so that the runout of the reamer can be prevented at high speeds, extending product life by suppressing the breakage caused by cutting resistance. The boring tool is inserted into a pilot hole formed in a workpiece beforehand to cut the inner wall of the pilot hole. The boring tool comprises a shank part rotated about an axis, an edge part with a cutting edge at the tip of the shank part, and a chip discharging groove formed in the outer peripheral part of the edge part and extending from the tip to the rear end. The cutting edge is formed at a crossed ridge part between the wall surface of the chip discharging groove and the outer peripheral surface of the edge part. The cross-section of the chip discharging groove is formed in a U-shape.

Dependencies are inferred from the claim text.