ASME B18.2.3.7M Heavy Hex Structural Bolts

Dia. D, and Thread Pitch	Body Diameter, D_s		Width Across Flats, S		Width Across Corners, E		Head Height, K		Wrenching Height, K₁		Washer Face Dia., Dw	Washer Face Thickness, C	Thread Length, B ^a		Transition Thread Length, X^b
	Body Diameter, D_s		Width Across Flats, S		Width Across Corners, E		Head Height, K		Wrenching Height, K₁		Washer Face Dia., Dw	Washer Face Thickness, C	Thread	Thread	Transition Thread Length, X^b
	Max	Min	Max	Min	Max	Min	Max	Min	Min	Min	Max	Min	Basic		Max
ANSI B18.2.3.7M - M16 × 2	16.7	15.3	27	26.16	31.18	29.56	10.75	9.25	6.5	24.9	0.8	0.4	31	38	6
ANSI B18.2.3.7M - M20 × 2.5	20.84	19.16	34	33	39.26	37.29	13.4	11.6	8.1	31.4	0.8	0.4	36	43	7.5
ANSI B18.2.3.7M - M22 × 2.5	22.84	21.16	36	35	41.57	39.55	14.9	13.1	9.2	33.3	0.8	0.4	38	45	7.5
ANSI B18.2.3.7M - M24 × 3	24.84	23.16	41	40	47.34	45.2	15.9	14.1	9.9	38	0.8	0.4	41	48	9
ANSI B18.2.3.7M - M27 × 3	27.84	26.16	46	45	53.12	50.85	17.9	16.1	11.3	42.8	0.8	0.4	44	51	9
ANSI B18.2.3.7M - M30 × 3.5	30.84	29.16	50	49	57.74	55.37	19.75	17.65	12.4	46.5	0.8	0.4	49	56	10.5
ANSI B18.2.3.7M - M36 × 4	37	35	60	58.8	69.28	66.44	23.55	21.45	15	55.9	0.8	0.4	56	63	12
a Basic thread length, B, is a reference dimension. b Transition thread length, X, includes the length of incomplete threads and tolerances on grip gaging length and body length. It is intended for calculation purposes. All dimensions are in millimeters. For additional manufacturing and acceptance specifications, reference should be made to the ANSI B18.2.3.7M-1979 (R1995) standard.