Screw Thread d				M4	M5	M6	(M7)	M8	M10	M12	(M14)	M16	(M18)	M20	(M22)	M24	(M27)	M30	(M33)	M36	(M39)	M42	(M45)	M48	(M52)
P		Pitch		0.7	0.8	1	1	1.25	1.5	1.75	2	2	2.5	2.5	2.5	3	3	3.5	3.5	4	4	4.5	4.5	5	5
a		max		2.1	2.4	3	3	3.75	4.5	5.25	6	6	7.5	7.5	7.5	9	9	10.5	10.5	12	12	13.5	13.5	15	15
c		min		0.15	0.15	0.15	0.15	0.15	0.15	0.15	0.15	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.3	0.3	0.3	0.3	0.3
		max		0.4	0.5	0.5	0.5	0.6	0.6	0.6	0.6	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	0.8	1	1	1	1	1
da		max		4.7	5.7	6.8	7.8	9.2	11.2	13.7	15.7	17.7	20.2	22.4	24.4	26.4	30.4	33.4	36.4	39.4	42.4	45.6	48.6	52.6	56.6
dw		Grade A	min	5.9	6.9	8.9	9.6	11.6	15.6	17.4	20.5	22.5	25.3	28.2	30	33.6	-	-	-	-	-	-	-	-	-
		Grade B	min	5.7	6.7	8.7	9.4	11.4	15.4	17.2	20.1	22	24.8	27.7	29.5	33.2	38	42.7	46.5	51.1	55.9	59.9	64.7	69.4	74.2
e		Grade A	min	7.66	8.79	11.05	12.12	14.38	18.9	21.1	24.49	26.75	30.14	33.53	35.72	39.98	-	-	-	-	-	-	-	-	-
		Grade B	min	7.5	8.63	10.89	11.94	14.2	18.72	20.88	23.91	26.17	29.56	32.95	35.03	39.55	45.2	50.85	55.37	60.79	66.44	71.3	76.95	82.6	88.25
k		Nominal Size		2.8	3.5	4	4.8	5.3	6.4	7.5	8.8	10	11.5	12.5	14	15	17	18.7	21	22.5	25	26	28	30	33
		Grade A	min	2.68	3.35	3.85	4.65	5.15	6.22	7.32	8.62	9.82	11.28	12.28	13.78	14.78	-	-	-	-	-	-	-	-	-
			max	2.92	3.65	4.15	4.95	5.45	6.56	7.68	8.98	10.18	11.72	12.72	14.22	15.22	-	-	-	-	-	-	-	-	-
		Grade B	min	2.6	3.26	3.76	4.56	5.06	6.11	7.21	8.51	9.71	11.15	12.15	13.65	14.65	16.65	18.28	20.58	22.08	24.58	25.58	27.58	29.58	32.5
			max	3	3.74	4.24	5.04	5.54	6.69	7.79	9.09	10.29	11.85	12.85	14.35	15.35	17.35	19.12	21.42	22.92	25.42	26.42	28.42	30.42	33.5
k1		min		1.9	2.28	2.63	3.19	3.54	4.28	5.05	5.96	6.8	7.8	8.5	9.6	10.3	11.7	12.8	14.4	15.5	17.2	17.9	19.3	20.9	22.8
r		min		0.2	0.2	0.25	0.25	0.4	0.4	0.6	0.6	0.6	0.6	0.8	0.8	0.8	1	1	1	1	1	1.2	1.2	1.6	1.6
s		max=nominal size		7	8	10	11	13	17	19	22	24	27	30	32	36	41	46	50	55	60	65	70	75	80
		Grade A	min	6.78	7.78	9.78	10.73	12.73	16.73	18.67	21.67	23.67	26.67	29.67	31.61	35.38	-	-	-	-	-	-	-	-	-
		Grade B	min	6.64	7.64	9.64	10.57	12.57	16.57	18.48	21.16	23.16	26.15	29.16	31	35	40	45	49	53.8	58.8	63.1	68.1	73.1	78.1

Related Knowlege : The 5.8 grade fasteners is also produced from middle carbon steel, meeting the required hardness and other mechanical characters, which material are all from china state-owned big manufacturer.