ASME B18.3.1M Metric Socket Head Cap Screws

Nominal Size and Thread Pitch	Body Diameter, D		Head Diameter, A		Head Height, H		Chamfer or Radius, S, Max	Hexagon Socket Size, J, Nom.	Spline Socket Size, M, Nom.	Key Engagement, T, Min	Transition Diameter, B^a, Max
Nominal Size and Thread Pitch	Max	Min	Max	Min	Max	Min	Chamfer or Radius, S, Max	Hexagon Socket Size, J, Nom.	Spline Socket Size, M, Nom.	Key Engagement, T, Min	Transition Diameter, B^a, Max
M1.6 x 0.35	1.60	1.46	3.00	2.87	1.60	1.52	0.16	1.5	1.829	0.80	2.0
M2 0.4	2.00	1.86	3.80	3.65	2.00	1.91	0.20	1.5	1.829	1.00	2.6
M2.5 x 0.45	2.50	2.36	4.50	4.33	2.50	2.40	0.25	2.0	2.438	1.25	3.1
M3 x 0.5	3.00	2.86	5.50	5.32	3.00	2.89	0.30	2.5	2.819	1.50	3.6
M4 x 0.7	4.00	3.82	7.00	6.80	4.00	3.88	0.40	3.0	3.378	2.00	4.7
M5 x 0.8	5.00	4.82	8.50	8.27	5.00	4.86	0.50	4.0	4.648	2.50	5.7
M6 x 1	6.00	5.82	10.00	9.74	6.00	5.85	0.60	5.0	5.486	3.00	6.8
M8 x 1.25	8.00	7.78	13.00	12.70	8.00	7.83	0.80	6.0	7.391	4.00	9.2
M10 x 1.5	10.00	9.78	16.00	15.67	10.00	9.81	1.00	8.0	--	5.00	11.2
M12 x 1.75	12.00	11.73	18.00	17.63	12.00	11.79	1.20	10.0	--	6.00	14.2
M14 x 2b	14.00	13.73	21.00	20.60	14.00	13.77	1.40	12.0	--	7.00	16.2
M16 x 2	16.00	15.73	24.00	23.58	16.00	15.76	1.60	14.0	--	8.00	18.2
M20 x 2.5	20.00	19.67	30.00	29.53	20.00	19.73	2.00	17.0	--	10.00	22.4
M24 x 3	24.00	23.67	36.00	35.48	24.00	23.70	2.40	19.0	--	12.00	26.4
M30 x 3.5	30.00	29.67	45.00	44.42	30.00	29.67	3.00	22.0	--	15.00	33.4
M36 x 4	36.00	35.61	54.00	43.37	36.00	35.64	3.60	27.0	--	18.00	39.4
M42 x 4.5	42.00	41.61	63.00	62.31	42.00	41.61	4.20	32.0	--	21.00	45.6
M48 x 5	48.00	47.61	72.00	71.27	48.00	47.58	4.80	36.0	--	24.00	52.6

^bThe M14X2 size is not recommended for use in new designs.
All dimensions are in millimeters
L_G is a grip length and L_B is body length.
For additional manufacturing and acceptance specificatons, see ASME B18.3.1M-1986.