| 摘要 |
PURPOSE:To perform a candle grinding quickly and simply, by polishing the tip of the edge of a drill by abutting to a ground angular part so that the circumferential part of a grindstone and the side face part become at an obtuse angle. CONSTITUTION:Grinding is executed so that the angular part X of the circumferential part 1a and the side face part 1b of a grindstone 1 become 160 deg.. The place Y slightly apart from the tip of the edge tip of a drill 2 is then abutted to the angular part X of the grindstone 1 and the edge tip of one part is polished. A belt like point 3 is then formed at the center part of the edge tip of the drill 2 by polishing the place Y' slightly apart from the tip of the edge tip in the opposite direction by turning the drill 2 180 deg.. The belt like point 3 is polished by abutting to the angular part X of the grindstone 1 by turning the drill 2 45 deg. to a ridge line Z. A port is formed by polishing the objective place of the belt like point 3 for the ridge line Z. Consequently, candle grinding optimum for working a thin plate can be performed simply and quickly. |
