Dimensions of Metric Heavy Hex Structural Bolts

Diameter, D, and Thread Pitch	Body Diameter Ds		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, Xo, Max
	Max	Min	Max	Min	Max	Min	Max	Min			Max	Min	Length ≤ 100	Length > 100
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.