2) Insert Shape: The insert shape is identified by a letter: H, hexagonal; O, octagonal; P, pentagonal; S, square; T, triangular; C, rhombic, 80° included angle; D, rhombic, 55° included angle; E, rhombic, 75° included angle; M, rhombic, 86° included angle; V, hombic, 35° included angle; W, hexagonal, 80° included angle; L, rectangular; A, parallelogram, 85° included angle; B, parallelogram, 82° included angle; K, parallelogram, 55° included angle; R, round. The included angle is always the smaller angle.

3) Holder Style: The holder style designates the shank style and the side cutting edge angle, or end cutting edge angle, or the purpose for which the holder is used. It is designated by a letter: A, for straight shank with 0° side cutting edge angle; B, straight shank with 15° side cutting edge angle; C, straight-shank end cutting tool with 0° end cutting edge angle; D, straight shank with 45° side cutting edge angle; E, straight shank with 30° side cutting edge angle; F, offset shank with 0° end cutting edge angle; G, offset shank with 0° side cutting edge angle; J, offset shank with negative 3° side cutting edge angle; K, offset shank with 15° end cutting edge angle; L, offset shank with negative 5° side cutting edge angle and 5° end cutting edge angle; M, straight shank with 40° side cutting edge angle; N, straight shank with 27° side cutting edge angle; R, offset shank with 15° side cutting edge angle; S, offset shank with 45° side cutting edge angle; T, offset shank with 30° side cutting edge angle; U, offset shank with negative 3° end cutting edge angle; V, straight shank with 171⁄2° side cutting edge angle; W, offset shank with 30° end cutting edge angle; Y, offset shank with 5° end cutting edge angle. Letter symbols for holder styles shown in the following figures;