DRILL BIT

摘要

A drill bit having a thinning is disclosed. The disclosed drill bit comprises a shank unit mounted on a holder of a drilling device and a body of the drill unit extended from one end of a shank unit into one body. A pair of chip discharge grooves are spirally formed on the outer periphery of the body of the drill unit. A pair of cutting blades, extended to the either side from a drill point and a chisel edge formed between the cutting blades, are formed on the top end part of the body of the drill unit. The thinning is formed in a concave groove shape in order to reduce the width of the chisel edge on both ends of the chisel edge, wherein the thinning is lengthways extended along the pair of the chip discharge grooves from the top end part of the body of the drill unit.