BS 3692

BS 3692 Specification

BS 3692 Bolts, BS 3692 Screws, BS 3692 Stud Bolts, BS 3692 Nuts

Recommended bolt and nut

Grade of bolt	4.6	4.8	5.6	5.8	6.8	8.8	8.8 A)	10.9	10.9 A)	12.9
Recommended grade of nut	4	4	5	5	6	8	10	10	12	12
The nuts in Table 7 are at least 15% lower in height than ISO metric ‘Regular’ nuts, in BS EN ISO 4032 for example. Therefore they are not capable of withstanding the same tensile loads without the risk of thread stripping (see also Foreword) Nuts of a higher strength grade may be substituted for nuts of a lower strength grade.

Chemical composition

Strength grade designation	Chemical composition limit s (check analy si s)
Strength grade designation	C max. %	Mn min. %	P max. %	S max. %
4, 5 and 6 (See notes)	0.5	0.11	0.15
8	0.58	0.3	0.06	0.15
10 and 12 (See notes)	0.58	0.45	0.048	0.058
Free cutting steel may be used only by special agreement between the purchaser and the supplier. In such cases, the following maximum phosphorus, sulfur and lead contents are permissible: Phosphorus, 0.12%; Sulfur, 0.34%; Lead, 0.35%.

Mechanical properties

Strength grade designation	4	5	6	8	10	12
Proof load stress A> MPa	400	500	600	800	1 000	1 200	– C)
Brinell hardness (HB) max.	302	302	302	302	353	375	All nuts
Rockwell hardness 8> (HRC) max.	30	30	30	30	36	39	All nuts
Vickers hardness (HV) max.	310	310	310	310	370	395	All nuts
A> The proof load is calculated by multiplying the proof load stress by the tensile stress area of the bolt . B> The conversion from Brinell hardness into Rockwell hardness has been calculated in accordance with BS EN ISO 6506-1 BS EN ISO 6506-2 and BS EN ISO 6506-3, and BS EN ISO 6508-1. C> All nuts other than those exempted by agreement between the purchaser and the manufacturer. Nuts with a specified proof load in excess of 500 000 N may be except from proof load test in g. Such nuts shall meet the minimum hardness as agreed between the purchaser and the manufacturer.

Proof loads
Tolerance standard
Tolerance classes
Thread lengths

Nominal size of ut m	Tensile stress area of bolt mm²	Strength grade designat ion
		4	5	6	8	10	12
		Stress under proof load MPa
		400	500	600	800	1000	1200
		Proof load N
M1.6	1.27	510	640	760	1020	1270	1520
M2	2.07	830	1030	1240	1650	2070	2480
M 2.5	3.39	1360	1700	2030	2710	3390	4070
M3	5.03	2010	2520	3020	4000	5000	6000
M4	8.78	3510	4400	5250	7000	8750	10500
M5	14.2	5680	7100	8500	11400	14200	17000
M6	20.1	8040	10000	12000	16000	20000	24000
M8	36.6	14600	18300	22000	29000	36500	43000
M10	58	23200	29000	35000	46000	58000	69500
M12	84.3	33700	42100	50500	67000	84000	100000
M14	115	46000	57500	69000	92000	115000	138000
M16	157	62800	78500	94000	125000	157000	188000
M18	192	76800	98000	115000	154000	192000	230000
M20	245	98000	122000	147000	196000	245000	294000
M22	303	121000	151000	182000	242000	303000	364000
M24	353	141000	175000	212000	282000	353000	423000
M27	459	184000	230000	276000	367000	459000	550000
M30	561	224000	280000	336000	448000	561000	673000
M33	694	278000	347000	416000	555000	694000	833000
M36	817	327000	408000	490000	653000	817000	980000
M39	976	390000	488000	585000	780000	976000	1170000
M42	1120	448000	560000	672000	896000	1120000	1340000
M45	1300	520000	650000	780000	1040000	1300000	1560000
M48	1470	588000	735000	882000	1180000	1470000	1760000
M52	1760	704000	880000	1060000	1410000	1760000	2110000
Proof load = Stress under proof x tensile stress area of bolt For stress under proof load Nuts with a specified proof load above 500 000 N force may be exempted from proof load testing.

Nominal length I	Tolerance	Nominal length I	Tolerance
5	±0.24	90	±0.70
6	±0.24	-95	±0.70
-7	±0.29	100	±0.70
8	±0.29	(105)	± 0.70
-9	±0.29	110	±0.70
10	±0.29	-115	±0.70
-11	±0.35	120	±0.70
12	±0.35	-125	±0.80
14	±0.35	130	±0.80
16	±0.35	140	±0.80
-18	±0.35	150	±0.80
20	±0.42	160	±0.80
-22	±0.42	170	±0.80
25	±0.42	180	±0.80
-28	±0.42	190	±0.925
30	±0.42	200	±0.925
-32	±0.50	220	±0.925
35	±0.50	240	±0.925
-38	±0.50	260	±1.05
40	±0.50	280	±1.05
45	±0.50	300	±1.05
50	±0.50	325	±1.15
55	±0.60	350	±1.15
60	±0.60	375	±1.15
65	±0.60	400	±1.15
70	±0.60	425	±1.25
75	±0.60	450	±1.25
80	±0.60	475	±1.25
85	±0.70	500	±1.25
Lengths shown in brackets are non-preferred. See also Annex D.

Product	Tolerance class
Bolts and screws	6g
Nuts (faced)	6H
Nuts (used with galvanized bolts)	GAZ (in accordance with BS ISO 965-5)

Nominal length of boltI	Length of thread b
Up to and including 125 mm	2d + 6 mm
Over 125 mm up to and including 200 mm	2d+12mm
Over 200 mm	2d + 25 mm

Hexagon bolts and screws
Hexagon bolts and screws
Hexagon nuts and thin nuts
Hexagon slotted nuts and castle nuts
Strength grade

Nominal size and thread diameter d	Pitch of (thread series)	Thread runout a max.	Diameter of shank d		Width across flats s		Width across corners e		Diameter of washer face d
Nominal size and thread diameter d	Pitch of (thread series)	Thread runout a max.	max.	min.	max.	min.	max.	min.	max.	min.
M1.6	0.35	0.8	1.6	1.46	3.2	3.08	3.7	3.48	–	–
M2	0.4	1	2	1.86	4	3.88	4.6	4.38	–	–
M2.5	0.45	1	2.5	2.23	5	4.88	5.8	5.51	–	–
M3	0.5	1.2	3	2.86	5.5	5.38	6.4	6.08	5.08	4.83
M4	0.7	1.6	4	3.82	7	6.85	8.1	7.74	6.55	6.3
M5	0.8	2	5	4.82	8	7.85	9.2	8.87	7.55	7.3
M6	1	2.5	6	5.82	10.0	9.78	11.5	11.05	9.48	9.23
M8	1.25	3	8	7.78	13.0	12.73	15.0	14.38	12.43	12.18
M10	1.5	3.5	10	9.78	17.0	16.73	19.6	18.9	16.43	16.18
M12	1.75	4	12	11.73	19.0	18.67	21.9	21.1	18.37	18.12
(M14)	2	5	14	13.73	22	21.67	25.4	24.49	21.37	21.12
M16	2	5	16	15.73	24	23.67	27.7	26.75	23.27	23.02
(M18)	2.5	6	18	17.73	27	26.67	31.2	30.14	26.27	26.02
M20	2.5	6	20	19.67	30.0	29.67	34.6	33.53	29.27	28.8
(M22)	2.5	6	22	21.67	32	31.61	36.9	35.72	31.21	30.74
M24	3	7	24	23.67	36	35.38	41.6	39.98	34.98	34.51
(M27)	3	7	27	26.67	41	40.38	47.3	45.63	39.98	39.36
M30	3.5	8	30	29.67	46	45.38	53.1	51.28	44.98	44.36
(M33)	3.5	8	33	32.61	50	49.38	57.7	55.8	48.98	48.36
M36	4	10	36	35.61	55	54.26	63.5	61.31	53.86	53.24
(M39)	4	10	39	38.61	60	59.26	69.3	66.96	58.86	58.24
M42	4.5	11	42	41.61	65	64.26	75.1	72.61	63.76	63.04
(M45)	4.5	11	45	44.61	70	69.26	80.8	78.26	68.76	68.04
M48	5	12	48	47.61	75	74.26	86.6	83.91	73.76	73.04
(M52)	5	12	52	51.54	80	79.26	92.4	89.56	–	–
M56	5.5	19	56	55.54	85	84.13	98.1	95.07	–	–
(M60)	5.5	19	60	59.54	90	89.13	103.9	100.72	–	–
M64	6	21	64	63.54	95	94.13	109.7	106.37	–	–
(M68)	6	21	68	67.54	100	99.13	115.5	112.02	–	–
Sizes shown in brackets are non-preferred

Nominal size and thread diameter d	Depth of washer face C	Transition diameter da max.	Radius under head r		Height of head k		Eccentricity of head max.	Eccentricity of shank and split pin hole to the thread max.
Nominal size and thread diameter d	Depth of washer face C	Transition diameter da max.	max.	min.	max.	min.	Eccentricity of head max.	Eccentricity of shank and split pin hole to the thread max.
M1.6	–	2	0.2	0.1	1.23	0.98	0.18	0.14
M2	–	2.6	0.3	0.1	1.53	1.28	0.18	0.14
M2.5	–	3.1	0.3	0.1	1.83	1.58	0.18	0.14
M3	0.1	3.6	0.3	0.1	2.13	1.9	0.18	0.14
M4	0.1	4.7	0.35	0.2	2.93	2.68	0.22	0.18
M5	0.2	5.7	0.35	0.2	3.66	3.35	0.22	0.18
M6	0.3	6.8	0.4	0.25	4.15	3.85	0.22	0.18
M8	0.4	9.2	0.6	0.4	5.65	5.35	0.27	0.22
M10	0.4	11.2	0.6	0.4	7.18	6.82	0.27	0.22
M12	0.4	14.2	1.1	0.6	8.18	7.82	0.33	0.27
(M14)	0.4	16.2	1.1	0.6	9.18	8.82	0.33	0.27
M16	0.4	18.2	1.1	0.6	10.18	9.82	0.33	0.27
(M18)	0.4	20.2	1.1	0.6	12.22	11.79	0.33	0.27
M20	0.4	22.4	1.2	0.8	13.22	12.79	0.33	0.33
(M22)	0.4	24.4	1.2	0.8	14.22	13.79	0.39	0.33
M24	0.5	26.4	1.2	0.8	15.22	14.79	0.39	0.33
(M27)	0.5	30.4	1.7	1	17.22	16.79	0.39	0.33
M30	0.5	33.4	1.7	1	19.26	18.74	0.39	0.33
(M33)	0.5	36.4	1.7	1	21.26	20.74	0.39	0.39
M36	0.5	39.4	1.7	1	23.26	22.74	0.46	0.39
(M39)	0.6	42.4	1.7	1	25.26	22.74	0.46	0.39
M42	0.6	45.6	1.8	1.2	26.26	25.74	0.46	0.39
(M45)	0.6	48.6	1.8	1.2	28.26	27.74	0.46	0.39
M48	0.6	52.6	2.3	1.6	30.26	29.74	0.46	0.39
(M52)	–	56.6	2.3	1.6	33.21	32.69	0.46	0.46
M56	–	63	3.5	2	35.31	34.69	0.54	0.46
(M60)	–	67	3.5	2	38.31	37.69	0.54	0.46
M64	–	71	3.5	2	40.31	39.69	0.54	0.46
(M68)	–	75.0	3.5	2	43.31	42.69	0.54	0.46
All true radius is not essential providing that the curve is smooth and lies wholly within the maximum radius, determined from the maximum transitional diameter and the minimum radius specified.

Nominal size and thread diameter d	Pitch of thread (coarse pitch series)	Width across flats s		Width across corners e		Thickness of normal nut m		Tolerance on squareness of thread to face of nut	Eccentricity of hexagon	Thickness of thin nut t
Nominal size and thread diameter d	Pitch of thread (coarse pitch series)	max.	min.	max.	min.	max.	min.	max.	max.	max.	min
M1.6	0.35	3.2	3.08	3.7	3.48	1.3	1.05	0.05	0.14	–	–
M2	0.4	4	3.88	4.6	4.38	1.6	1.35	0.06	0.14	–	–
M.2	0.45	5	4.88	5.8	5.51	2	1.75	0.08	0.14	–	–
M3	0.5	5.5	5.38	6.4	6.08	2.4	2.15	0.09	0.14	–	–
M4	0.7	7	6.85	8.1	7.74	3.2	2.9	0.11	0.18	–	–
M5	0.8	8.00	7.85	9.2	8.87	4	3.7	0.13	0.18	–	–
M6	1	10	9.78	11.5	11.05	5	4.7	0.17	0.18	–	–
M8	1.25	13	12.73	15	14.38	6.5	6.14	0.22	0.22	5	4.7
M10	1.5	17	16.73	19.6	18.9	8	7.64	0.29	0.22	6	5.7
M12	1.75	19	18.67	21.9	21.1	10	9.64	0.32	0.27	7	6.64
(M14)	2	22	21.67	25.4	24.49	11	10.57	0.37	0.27	8	7.64
M16	2	24	23.67	27.7	26.75	13	12.57	0.41	0.27	8	7.64
(M18)	2.5	27	26.67	31.2	30.14	15	14.57	0.46	0.27	9	8.64
M20	2.5	30	29.67	34.6	33.53	16	15.57	0.51	0.33	9	8.64
(M22)	2.5	32	31.67	36.9	35.72	18	17.57	0.54	0.33	10	9.64
M24	3	36	35.38	41.6	39.98	19	18.48	0.61	0.33	10	9.64
(M27)	3	41	40.38	47.3	45.63	22	21.48	0.7	0.33	12	11.57
M30	3.5	46	45.38	53.1	51.28	24	23.48	0.78	0.33	12	11.57
(M33)	3.5	50	49.38	57.7	55.8	26	25.48	0.85	0.39	14	13.57
M36	4	55	54.26	63.5	61.31	29	28.48	0.94	0.39	14	13.57
(M39)	4	60	59.26	69.3	66.96	31	30.38	1.03	0.39	16	15.57
M42	4.5	65	64.26	75.1	72.61	34	33.38	1.11	0.39	16	15.57
(M45)	4.5	70	69.26	80.8	78.26	36	35.38	1.2	0.39	18	17.57
M48	5	75	74.26	86.6	83.91	38	37.38	1.29	0.39	18	17.57
(M52)	5	80	79.26	92.4	89.56	42	41.38	1.37	0.46	20	19.48
M56	5.5	85	84.13	98.1	95.07	45	44.38	1.46	0.46	–	–
(M60)	5.5	90	89.13	103.9	100.72	48	47.38	1.55	0.46	–	–
M64	6	95	94.13	109.7	106.37	51	50.26	1.63	0.46	–	–
Sizes shown in brackets are non-preferred For tolerances on squareness of thread to face of nut

Nominal size and thread diameter d	Diameter d2		Thickness h		Lower face of nut to bottom of slot m		Width of slot n		Radius (0.25n) r	Nominal size of split pin and nominal drill	Eccentricity of the slots max.
Nominal size and thread diameter d	max.	min.	max.	min.	max.	min.	max.	min.	min.	Nominal size of split pin and nominal drill	Eccentricity of the slots max.
M4	–	–	5	4.7	3.2	2.9	1.45	1.2	0.3	It is intended to provide appropriate values in this column once International agreement has been reached on metric series split cotter pins	0.18
M5	–	–	6	5.7	4	3.7	1.65	1.4	0.35		0.18
M6	–	–	7.5	7.14	5	4.7	2.25	2	0.5		0.18
M8	–	–	9.5	9.14	6.5	6.14	2.75	2.5	0.625		0.22
M10	–	–	12	11.57	8	7.64	3.05	2.8	0.7		0.22
M12	17	16.57	15	14.57	10	9.64	3.8	3.5	0.875		0.27
(M14)	19	18.48	16	15.57	11	10.57	3.8	3.5	0.875		0.27
M16	22	21.48	19	18.48	13	12.57	4.8	4.5	1.125		0.27
(M18)	25	24.48	21	20.48	15	14.57	4.8	4.5	1.125		0.27
M20	28	27.48	22	21.48	16	15.57	4.8	4.5	1.125		0.33
(M22)	30	29.48	26	25.48	18	17.57	5.8	5.5	1.375		0.33
M24	34	33.38	27	26.48	19	18.48	5.8	5.5	1.375		0.33
(M27)	38	37.38	30	29.48	22	21.48	5.8	5.5	1.375		0.33
M30	42	41.38	33	32.38	24	23.48	7.36	7	1.75		0.33
(M33)	46	45.38	35	34.38	26	25.48	7.36	7	1.75		0.39
M36	50	49.38	38	37.38	29	28.48	7.36	7	1.75		0.39
(M39)	55	54.26	40	39.38	31	30.38	7.36	7	1.75		0.39
M42	58	57.26	46	45.38	34	33.38	9.36	9	2.25		0.39
(M45)	62	61.26	48	47.38	36	35.38	9.36	9	2.25		0.39
M48	65	64.26	50	49.38	38	37.38	9.36	9	2.25		0.39
(M52)	70	69.26	54	53.26	42	41.38	9.36	9	2.25		0.46
M56	75	74.26	57	56.26	45	44.38	9.36	9	2.25		0.46
(M60)	80	79.26	63	62.26	48	47.38	11.43	11	2.75		0.46
M64	85	84.13	66	65.26	51	50.26	11.43	11	2.75		0.46
M68	90	89.13	69	68.26	54	53.26	11.43	11	2.75		0.46
For width across flats and widths across corners, Sizes shown in brackets are non-preferred

Strength grade designation	4	5	6	8	10	12
Proof load stress MPa	400	500	600	800	1000	1200

Finishes

Strength grade designation	4	5	6	8	10	12
Proof load stress A> MPa	400	500	600	800	1 000	1 200	– C)
Brinell hardness (HB) max.	302	302	302	302	353	375	All nuts
Rockwell hardness 8> (HRC) max.	30	30	30	30	36	39	All nuts
Vickers hardness (HV) max.	310	310	310	310	370	395	All nuts
A> The proof load is calculated by multiplying the proof load stress by the tensile stress area of the bolt . B> The conversion from Brinell hardness into Rockwell hardness has been calculated in accordance with BS EN ISO 6506-1 BS EN ISO 6506-2 and BS EN ISO 6506-3, and BS EN ISO 6508-1. C> All nuts other than those exempted by agreement between the purchaser and the manufacturer. Nuts with a specified proof load in excess of 500 000 N may be except from proof load test in g. Such nuts shall meet the minimum hardness as agreed between the purchaser and the manufacturer.

Marking of nuts

Strength grade designation	8	10	12
Marking symbol	181	1101	1121

Coating Specifications

Renowned Brands

Marking

Product Shall be Marked with our manufacturing trade mark Adfast Component LTD along with the designated Grade.
Grade and manufacturer’s identification symbols shall be applied to one end of studs and to the heads of bolts and screws of all sizes. (If the available area is inadequate, the grade symbol may be marked on one end and the manufacturer’s identification symbol marked on the other end.) For bolts and screws smaller than 1⁄4 in. [6 mm] in diameter and studs smaller than 3⁄8 in. [10 mm] in diameter and for 1⁄4 in. [6 mm] in diameter studs requiring more than a total of three symbols, the marking shall be a matter of agreement between the purchaser and the manufacturer.

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