GOST 7811-70 Hexagon Reduced Head Bolts with Guide Neck, Product Grade A. Construction and Dimensions

GOST 7811-70 applies to hexagon reduced head bolts with guide neck, product grade A, with thread diameter from 6 to 48 mm.

HEXAGON REDUCED HEAD BOLTS WITH GUIDE NECK, PRODUCT GRADE A Construction and dimensions Hexagon reduced head bolts with guide neck product grade A. Construction and dimensions	GOST 7811-70

The design and dimensions of bolts shall conform to those shown in the drawing and in Tables 1 and 2.

Thread — per GOST 24705. Thread runout and incomplete thread — per GOST 27148. Bolt ends — per GOST 12414.

Radius under the head — per GOST 24670.

Tolerances on dimensions, form and position deviations, and inspection methods not established by this standard — per GOST 1759.1.

Permissible surface defects of bolts and inspection methods are per GOST 1759.2.

By agreement between the manufacturer and the customer, it is permitted to manufacture:

• bolts of types 1 and 2 with head height equal to k₁;
• bolts with nominal thread diameter from 36 to 48 mm with thread pitch of 2 mm.

The head design variant is determined by the manufacturer.

For marking purposes, it is allowed to manufacture bolts of types 1 and 2 with a recess on the end face of the head, with dimensions that do not reduce the strength of the head; the recess depth must not exceed 0.4 k.

Technical requirements — per GOST 1759.0.

The mass of bolts is given in Appendix 1.

Table 1

mm

Nominal thread diameter d		6	8	10	12	(14)	16	(18)	20	(22)	24	(27)	30	36	42	48
Thread pitch	coarse	1	1.25	1.5	1.75	2		2.5			3		3.5	4	4.5	5
	fine	-	1	1.25		1.5					2			3
Shank diameter d₁ h13		6	8	10	12	14	16	18	20	22	24	27	30	36	42	48
Guide neck height h, min		3	4	5	6	7	8	9	10	11	12	14	15	18	21	24
Width across flats S		10	12	14	17	19	22	24	27	30	32	36	41	50	60	70
Head height k		4	5	6	7	8	9	10	11	12	13	15	17	20	23	26
Head height k₁		4.2	5.3	6.4	7.5	8.8	10.0	12.0	12.5	14.0	15.0	17.0	18.7	22.5	26.0	30.0
Circumscribed circle diameter e, min		11.0	13.2	15.5	18.9	21.1	24.5	26.8	30.1	33.5	35.7	40.0	45.6	55.8	67.0	78.3
d w, min		8.9	10.6	12.6	15.6	17.4	20.6	22.5	25.3	28.2	30.0	33.6	38.4	46.9	56.3	65.8
h w	min	0.15				0.20									0.25
	max	0.6				0.8
Diameter of hole in shank d₃		1.6	2.0	2.5	3.2		4.0			5.0			6.3		8.0
Diameter of hole in head d₄ H15		2.0	2.5		3.2		4.0							5.0
Distance from bearing surface to axis of hole in head l₂ js15		2.0	2.8	3.5	4.0	4.5	5.0	6.0	6.5	7.0	7.5	8.5	9.5	11.5	13.0	15.0

Note. Bolt dimensions shown in parentheses are not recommended for use.

Table 2

mm

Bolt length l	Thread length b and distance from head bearing surface to axis of hole in shank l₁, at nominal thread diameter d
	6		8		10		12		(14)		16		(18)		20		(22)		24		(27)		30		36		42		48
	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b	l ₁	b
(28)	24	18	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
30	26	18	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
(32)	28	18	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
35	31	18	31	22	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
(38)	34	18	34	22	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
40	36	18	36	22	36	26	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
45	41	18	41	22	41	26	40	30	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
50	46	18	46	22	46	26	45	30	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
55	51	18	51	22	51	26	50	30	50	34	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
60	56	18	56	22	56	26	55	30	55	34	54	38	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
65	61	18	61	22	61	26	60	30	60	34	59	38	59	42	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
70	66	18	66	22	66	26	65	30	65	34	64	38	64	42	64	46	-	-	-	-	-	-	-	-	-	-	-	-	-	-
75	71	18	71	22	71	26	70	30	70	34	69	38	69	42	69	46	68	50	-	-	-	-	-	-	-	-	-	-	-	-
80	76	18	76	22	76	26	75	30	75	34	74	38	74	42	74	46	73	50	73	54	-	-	-	-	-	-	-	-	-	-
(85)	81	18	81	22	81	26	80	30	80	34	79	38	79	42	79	46	78	50	78	54	-	-	-	-	-	-	-	-	-	-
90	86	18	86	22	86	26	85	30	85	34	84	38	84	42	84	46	83	50	83	54	82	60	-	-	-	-	-	-	-	-
(95)	-	-	91	22	91	26	90	30	90	34	89	38	89	42	89	46	88	50	88	54	87	60	-	-	-	-	-	-	-	-
100	-	-	96	22	96	26	95	30	95	34	94	38	94	42	94	46	93	50	93	54	92	60	91	66	-	-	-	-	-	-
(105)	-	-	-	-	101	26	100	30	100	34	99	38	99	42	99	46	98	50	98	54	97	60	96	66	-	-	-	-	-	-
110	-	-	-	-	106	26	105	30	105	34	104	38	104	42	104	46	103	50	103	54	102	60	101	66	-	-	-	-	-	-
(115)	-	-	-	-	111	26	110	30	110	34	109	38	109	42	109	46	108	50	108	54	107	60	106	66	105	78	-	-	-	-
120	-	-	-	-	116	26	115	30	115	34	114	38	114	42	114	46	113	50	113	54	112	60	111	66	110	78	-	-	-	-
(125)	-	-	-	-	121	26	120	30	120	34	119	38	119	42	119	46	118	50	118	54	117	60	116	66	115	78	-	-	-	-
130	-	-	-	-	126	32	125	36	125	40	124	44	124	48	124	52	123	56	123	60	122	66	121	72	120	84	-	-	-	-
140	-	-	-	-	136	32	135	36	135	40	134	44	134	48	134	52	133	56	133	60	132	66	131	72	130	84	128	96	-	-
150	-	-	-	-	146	32	145	36	145	40	144	44	144	48	144	52	143	56	143	60	142	66	141	72	140	84	138	96	138	108
160	-	-	-	-	156	32	155	36	155	40	154	44	154	48	154	52	153	56	153	60	152	66	151	72	150	84	148	96	148	108
170	-	-	-	-	166	32	165	36	165	40	164	44	164	48	164	52	163	56	163	60	162	66	161	72	160	84	158	96	158	108
180	-	-	-	-	176	32	175	36	175	40	174	44	174	48	174	52	173	56	173	60	172	66	171	72	170	84	168	96	168	108
190	-	-	-	-	186	32	185	36	185	40	184	44	184	48	184	52	183	56	183	60	182	66	181	72	180	84	178	96	178	108
200	-	-	-	-	196	32	195	36	195	40	194	44	194	48	194	52	193	56	193	60	192	66	191	72	190	84	188	96	188	108
220	-	-	-	-	-	-	215	49	215	53	214	57	214	61	214	65	213	69	213	73	212	79	211	85	210	97	208	109	208	121
240	-	-	-	-	-	-	235	49	235	53	234	57	234	61	234	65	233	69	233	73	232	79	231	85	230	97	228	109	228	121
260	-	-	-	-	-	-	255	49	255	53	254	57	254	61	254	65	253	69	253	73	252	79	251	85	250	97	248	109	248	121
280	-	-	-	-	-	-	-	-	275	53	274	57	274	61	274	65	273	69	273	73	272	79	271	85	270	97	268	109	268	121
300	-	-	-	-	-	-	-	-	295	53	294	57	294	61	294	65	293	69	293	73	292	79	291	85	290	97	288	109	288	121

Note. Bolts with lengths shown in parentheses are not recommended for use.

Example of designation for a design 1 bolt with thread diameter d = 12 mm, length l = 60 mm, coarse pitch thread with tolerance class 6g, property class 5.8, plain:

Bolt M12-6g×60.58 GOST 7811-70

Same, design 2, with fine pitch thread with tolerance class 6g, property class 10.9, made of steel grade 40Kh, with coating 01, thickness 6 µm:

Bolt 2M12×1.25-6g×60.109.40Kh.016 GOST 7811-70

Mass of steel bolts (design 1) with coarse pitch thread

Bolt length l, mm	Theoretical mass of 1000 bolts, kg, at nominal thread diameter d, mm
	6	8	10	12	14	16	18	20	22	24	27	30	36	42	48
28	8.236	-	-	-	-	-	-	-	-	-	-	-	-	-	-
30	8.589	-	-	-	-	-	-	-	-	-	-	-	-	-	-
32	8.942	-	-	-	-	-	-	-	-	-	-	-	-	-	-
35	9.472	17.25	-	-	-	-	-	-	-	-	-	-	-	-	-
38	10.020	18.21	-	-	-	-	-	-	-	-	-	-	-	-	-
40	10.360	18.84	30.27	-	-	-	-	-	-	-	-	-	-	-	-
45	11.240	20.44	32.78	50.11	-	-	-	-	-	-	-	-	-	-	-
50	12.120	22.03	35.29	53.75	-	-	-	-	-	-	-	-	-	-	-
55	13.010	23.63	37.81	57.38	79.81	-	-	-	-	-	-	-	-	-	-
60	13.890	25.22	40.32	61.02	84.79	116.6	-	-	-	-	-	-	-	-	-
65	14.780	26.81	42.83	64.66	89.77	123.3	157.6	-	-	-	-	-	-	-	-
70	15.660	28.41	45.35	68.30	94.74	130.0	165.8	213.7	-	-	-	-	-	-	-
75	16.540	30.00	47.86	71.94	99.72	136.6	174.1	224.1	281.7	-	-	-	-	-	-
80	17.420	31.60	50.37	75.58	104.70	143.3	182.4	234.5	294.5	353.2	-	-	-	-	-
85	18.310	33.19	52.88	79.22	109.70	150.0	190.7	245.0	307.3	368.2	-	-	-	-	-
90	19.190	34.78	55.40	82.87	114.70	156.6	198.9	255.6	320.1	383.2	509.8	-	-	-	-
95	-	36.38	57.91	86.51	119.60	163.3	207.2	265.8	332.9	398.2	529.2	-	-	-	-
100	-	37.97	60.42	90.15	124.60	170.0	216.5	276.2	345.8	413.2	548.5	709.5	-	-	-
105	-	-	62.93	93.79	129.60	176.6	223.7	286.6	358.5	428.2	567.9	733.2	-	-	-
110	-	-	65.45	97.43	134.50	185.3	231.7	297.0	371.3	443.2	587.2	757.0	-	-	-
115	-	-	67.96	101.10	139.50	190.0	240.3	307.4	384.1	458.2	606.6	780.7	1198	-	-
120	-	-	70.47	104.80	144.50	196.6	248.6	317.9	396.9	473.2	625.9	804.4	1232	-	-
125	-	-	72.99	108.40	149.50	203.3	256.8	328.3	409.7	488.2	645.3	828.1	1267	-	-
130	-	-	75.50	112.00	154.50	210.0	265.1	338.7	422.5	503.2	664.7	851.8	1301	-	-
140	-	-	80.52	119.00	164.40	223.3	281.7	359.5	448.1	533.2	703.7	899.2	1370	1985	-
150	-	-	85.52	126.60	174.40	236.6	298.2	380.4	473.8	563.2	762.0	946.1	1439	2080	2864
160	-	-	90.57	133.90	184.40	250.0	314.7	401.2	499.4	593.2	800.8	994.1	1508	2174	2988
170	-	-	95.59	141.20	194.40	263.3	331.3	422.0	525.0	623.2	819.6	1041.0	1577	2268	3111
180	-	-	100.70	148.40	204.20	286.6	347.8	442.9	550.6	653.2	858.3	1089.0	1646	2362	3235
190	-	-	105.70	155.70	214.20	290.0	364.4	463.0	576.2	683.2	897.0	1136.0	1714	2456	3358
200	-	-	110.70	163.00	224.10	303.3	380.9	484.5	601.3	713.2	935.7	1184.0	1783	2551	3482
220	-	-	-	177.50	244.00	330.0	414.0	526.2	653.1	773.2	1013.0	1279.0	1921	2739	3729
240	-	-	-	192.20	263.90	356.6	447.1	567.9	704.3	833.2	1091.0	1373.0	2059	2927	3976
260	-	-	-	206.70	283.80	383.3	480.2	609.5	755.5	893.3	1168.0	1468.0	2196	3116	4223
280	-	-	-	-	303.70	410.0	513.3	651.2	806.7	953.3	1246.0	1563.0	2334	3304	4471
300	-	-	-	-	323.60	426.6	546.4	692.9	858.0	1014.0	1323.0	1658.0	2472	3493	4718

To determine the mass of bolts made of other materials, the mass values given in the table should be multiplied by the following coefficients: 0.356 for aluminium alloy; 1.080 for brass.

Referenced regulatory and technical documents are given in Table 5.

Designation of the referenced regulatory document	Clause number	Designation of the referenced regulatory document	Clause number
GOST 1759.0-87	6	GOST 24670-81	3a
GOST 1759.1-82	3 ,	GOST 24705-81	3
GOST 1759.2-82	3v	GOST 27148-86	3
GOST 12414-94	3

Corresponds to DIN 15237.