Dimensions for ISO 14581 Hexalobular socket countersunk flat head screws

Thread d	p	b	dk			kc	r	Inner Hexalobular
			teoretic	actual				hexalobular number	A	t
		min	max	nom=max	min.	nom.=max	max		ref.	max	min
M 2	without mounting shaft	25	4.4	3.8	3.5	1.2	0.5	6	1.75	0.64	0.51
M 2.5		25	5.5	4.7	4.4	1.5	0.6	8	2.4	0.79	0.66
M 3		25	6.3	5.5	5.2	1.65	0.8	10	2.8	0.83	0.7
M 3.5		38	8.2	7.3	6.94	2.35	0.9	15	3.35	1.32	1.16
M 4		38	9.4	8.4	8.04	2.7	1	20	3.95	1.53	1.14
M 5	Stepped shaft	38	10.4	9.3	8.94	2.7	1.3	25	4.5	1.51	1.12
M 6		38	12.6	11.3	10.87	3.3	1.5	30	5.6	1.78	1.39
M 8		38	17.3	15.8	15.37	4.65	2	45	7.95	2.54	2.15
M 10		38	20	18.3	17.78	5	2.5	50	8.98	2.8	2.41