| 摘要 |
PROBLEM TO BE SOLVED: To provide a single-edged blade drill capable of stabilizing bites to a material to be cut, preventing fractures and crushes of a chisel point part when biting the material to be cut to maintain high bore position accuracy over a long time, and rarely causing dispersion of quality in manufacturing. SOLUTION: In structure of this single-edged blade drill having one cutting blade 3 and one chip discharging groove 4, a relief part at a tip is constituted by multiple steps of flanks. A first ridge line formed by crossing two flanks exists at a cutting edge of the drill, and is positioned at a rotary center of the drill perpendicular to an axial core of the drill. A second ridge line formed by crossing two flanks is communicated with one end of the first ridge line. A main cutting blade is communicated with the outer end of the second ridge line, and the other end of the first ridge line is directed opposite to the side communicated with the second ridge line. COPYRIGHT: (C)2006,JPO&NCIPI
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