HOLE PROCESSING METHOD AND BORING TOOL

To provide a method for realizing the efficient hole processing.SOLUTION: A hole processing method comprises the steps of: relatively rotating a processing object material 3 with respect to a boring tool; and relatively feeding the boring tool with respect to the processing object material 3 in a direction at a prescribed angle with respect to a rotation axial line of the processing object material 3 in such a state that a first cutting edge 11 and a nose cutting edge 13 are cut into the inner surface of the hole of the processing object material 3. In the feeding step, an angle formed between a line segment connecting the boundary point between the first cutting edge 11 and the nose cutting edge 13 to the nose center of the nose cutting edge 13 and a line segment connecting a point at which the nose cutting edge 13 cuts into the inner surface of the hole with the largest amount to the nose center is set to be 30 degrees or less. An angle formed by the first cutting edge 11 cutting into the processing object material 3 with respect to a surface vertical to the longitudinal direction of a shank is set to be within a prescribed range.SELECTED DRAWING: Figure 4 【課題】効率的な穴加工を実現するための方法を提供する。【解決手段】穴加工方法は、中ぐり工具に対して被加工材３を相対回転させる工程と、被加工材３の穴の内面に第１切れ刃１１およびノーズ切れ刃１３を切り込ませた状態で、被加工材３の回転軸線に対して所定の角度となる方向に被加工材３に対して中ぐり工具を相対的に送る工程とを有する。送り工程において、第１切れ刃１１およびノーズ切れ刃１３の境界点とノーズ切れ刃１３のノーズ中心とを結ぶ線分と、ノーズ切れ刃１３が穴の内面を最も大きく切り込む点とノーズ中心とを結ぶ線分とのなす角度が３０度以内に設定され、シャンクの長手方向に垂直な面に対して、被加工材３に切り込む第１切れ刃１１のなす角度が、所定の範囲内に設定される。【選択図】図４