2b thread class, right-hand thread direction, 0.140 inches minimum nut and 0.143 inches maximum nut counterbore diameter, 0.187 inches nominal nut length, 0.166 inches minimum overall and 0.167 inches maximum overall boss diameter, 0.105 inches minimum overall and 0.110 inches maximum overall boss thickness

An internally threaded item with a cylindrical and/or square, hexagonal, octagonal, or dodecagonal outer periphery (parallel to the threaded axis) a portion(s) of which may or may not be enlarged, forming a flange(s) and/or shoulder(s). Items not having an enlarged outer portion may be threaded, a part of the full length, or tapped from both ends. Items having an enlarged outer portion (flange(s) or shoulder(s)) may be threaded the full length, threaded a part of the full length, or tapped from both ends. Items tapped from both ends shall have either right-hand threads on both ends or left-hand threads on both ends. For items conforming to any of the above and having a length overall exceeding two times the largest outside diameter or width across flats, use post, electrical-mechanical equipment. For items with an outside contour that is the same the full length, having a continuous thread through its entire length, and the length does not exceed two times the diameter or width across the flats use nut (1), plain (as modified). Excludes:nut (1), plain, cap. See also turnbuckle body.