| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface treatment drill whose cutting part is not damaged even when a drilling process is carried out by means of a manual feeding type drill press and a handheld electric drill or the like.SOLUTION: In the outer periphery of an apical end portion of a drill main body 1 with a columnar outer shape are formed chip discharge grooves 4 extending toward the rear end of the main body. At the apical ends of the chip discharge grooves 4 are formed cutting blades 6. In the apical end surface 5 of the drill main body 1, a range shorter than a range in which the chip discharge grooves 4 are formed between the apical end and the rear end of the drill main body 1, and the whole inner wall faces of the chip discharge grooves 4, of the outer peripheral surface of the drill main body 1 is formed a treatment layer 7 subjected to nitriding treatment or oxidation treatment or both nitriding and oxidation treatments. In addition, between the range in which the treatment layer 7 is formed and the range in which the chip discharge groove 4 near the rear end is formed, on the outer peripheral surface of the drill main body 1 is provided a non-treatment portion 8 in which the treatment portion 7 is not formed. |
