Longitudinal direction (rolling direction) of cold working plate 11 L and cross direction are designated as W. In this case, as for layout direction of sinking nail reform tool material 13, longitudinal direction of substance section material 13a (in reform tool itself 3 correspondence), cross direction W and abbreviates agrees, makes the direction where formation direction of nail retention section material 13b (in nail retention section 5 correspondence) process direction and abbreviates agrees of the cold working plate. Namely, longitudinal direction of reform tool itself 3 of sinking nail reform tool 1 it is abbreviation vertical (W direction) vis-a-vis the process direction of cold working plate 11, in order for formation direction of nail retention section 5 process direction and to abbreviate to agree L direction) of cold working plate 11, from cold working plate 11 sinking nail reform tool material 13 being quarried out with one body, it is processed.冷間加工板材11の長手方向(圧延方向)をL、幅方向をWとする。この場合、陥入爪矯正具素材13の地取り方向は、本体部素材13a(矯正具本体3に対応)の長手方向が、幅方向Wと略一致し、爪保持部素材13b(爪保持部5に対応)の形成方向が冷間加工板材の加工方向と略一致する方向とする。すなわち、陥入爪矯正具1の矯正具本体3の長手方向が冷間加工板材11の加工方向に対して略垂直(W方向)であり、爪保持部5の形成方向が冷間加工板材11の加工方向と略一致(L方向)するように、冷間加工板材11から陥入爪矯正具素材13が一体で切り出されて加工される。
