| 摘要 |
PROBLEM TO BE SOLVED: To provide a drill for machining a hole as cast which suppresses deterioration of hole position accuracy, when machining a hole as cast of a cast product. SOLUTION: In this drill, a distal end angleθ1 is set to more than an almost 170°and less than an almost 180°, and radial component force of cutting resistance (and a difference of the radial component force) is reduced as compared with that in a conventional drill, to prevent eccentricity of the drill. As a result, deterioration of the hole position accuracy is suppressed. COPYRIGHT: (C)2006,JPO&NCIPI |
