ASME B18.2.3.7M Metric Heavy Hex Structural Bolts

Diameter, D, and Thread Pitch	Body Diameter D_s		Width Across Flats, S		Width Across Corners, E		Head Height, K		Wrenching Height, K1, Min	Washer Face Diameter, Dw, Min	Washer Face Thickness, C		Thread Length, B, Basic		Transition Thread Length, X^o, Max
Diameter, D, and Thread Pitch	Max	Min	Max	Min	Max	Min	Max	Min	Wrenching Height, K1, Min	Washer Face Diameter, Dw, Min	Max	Min	Length ≤ 100	Length > 100	Transition Thread Length, X^o, Max
M16 x 2	16.70	15.30	27.00	26.16	31.18	29.56	10.75	9.25	6.5	24.9	0.8	0.4	31	38	6.0
M20 x 2.5	20.84	19.16	34.00	33.00	39.26	37.29	13.40	11.60	8.1	31.4	0.8	0.4	36	43	7.5
M22 x 2.5	22.84	21.16	36.00	35.00	41.57	39.55	14.90	13.10	9.2	33.3	0.8	0.4	38	45	7.5
M24 x 3	24.84	23.16	41.00	40.00	47.34	45.20	15.90	14.10	9.9	38.0	0.8	0.4	41	48	9.0
M27 x 3	27.84	26.16	46.00	45.00	53.12	50.85	17.90	16.10	11.3	42.8	0.8	0.4	44	51	9.0
M30 x 3.5	30.84	29.16	50.00	49.00	57.74	55.37	19.75	17.65	12.4	46.5	0.8	0.4	49	56	10.5
M36 x 4	37.00	35.00	60.00	58.80	69.28	66.44	23.55	21.45	15.0	55.9	0.8	0.4	56	63	12.0

^aBasic thread length, B, is a reference dimension.
^bTransition 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 ANSIB18.2.3.7M-1979, R1995 standard.