Dimensions of Metric Heavy Hex Bolts

Nominal Bolt Diameter, D, and Thread Pitch	Body Diameter Ds		Width Across Flats, S		Width Across Corners, E		Head Height, K		Wrenching Height, K1
	Max	Min	Max	Min	Max	Min	Max	Min	Min
M12 x 1.75	12.70	11.30	21.00	20.16	24.25	22.78	7.95	7.24	5.2
M14 x 2	14.70	13.30	24.00	23.16	27.71	26.17	9.25	8.51	6.2
M16 x 2	16.70	15.30	27.00	26.16	31.18	29.56	10.75	9.68	7.0
M20 x 2.5	20.84	19.16	34.00	33.00	39.26	37.29	13.40	12.12	8.8
M24 x 3	24.84	23.16	41.00	40.00	47.34	45.20	15.90	14.56	10.5
M20 x 3.5	30.84	29.16	50.00	49.00	57.74	55.37	19.75	17.92	13.1
M36 x 4	37.00	35.00	60.00	58.80	69.28	66.44	23.55	21.72	15.8

All dimensions are in millimeters.
Basic thread lengths, B, are same as given in table 12 of ASME B18.2.3.6M.
For additional manufacturing and acceptance specification, reference should be made to ASME B18.2.3.6M-1979, R1989 standard.