Single-flute drill for printed wiring boards

Abstract

The objective of this invention is to provide a single-flute drill bit for printed circuit boards that can minimize the residue of burrs even when the corner of the cutting edge is worn. The means to solve this problem is a single-flute drill bit for printed circuit boards in which, in the edge portion (9), between a first position (P1) closest to the front end of the drill body on both the clearance surface (10) on the side excluding the back of the first cutting edge (7) and the clearance surface (10') on the side excluding the back of the second cutting edge (8), and a second position in the edge portion (9) separated by 0.25 mm from the base end of the drill body on the edge portion (9) toward the front end of the drill body, the angle (θ) formed by the line connecting the first leading edge (X) and the drill rotation center axis (O) and the line connecting the second leading edge (Y) and the drill rotation center axis (O) on a plane orthogonal to the drill rotation center axis (O) is configured to gradually increase from the first position (P1) toward the second position (P2).

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