GOST 11644-75 Rounded-Off Pan-Head Screws, Product Grades A and B. Construction and Dimensions

GOST 11644-75 establishes the construction and dimensions of rounded-off pan-head screws, product grades A and B, with a nominal thread diameter from 2 to 10 mm. The standard fully corresponds to ST SEV 2654-80 and DIN 967.

The construction and dimensions of the screws shall comply with those specified in Tables 1, 2 and the drawing.

ROUNDED-OFF PAN-HEAD SCREWS, PRODUCT GRADES A AND B Construction and dimensions Rounded-off pan-head screws product grades A and B. Construction and dimensions	GOST 11644-75* (ST SEV 2654-80) Supersedes GOST 11644-75

Table 1, mm

Nominal thread diameter d		2	2.5	3	3.5	4	5	6	8	10
Thread pitch P	coarse	0.4	0.45	0.5	0.6	0.7	0.8	1	1.25	1.5
	fine	-	-	-	-	-	-	-	1	1.25
Head diameter D		4	5	6	7	8	10	12	16	20
Head heightr		1.2	1.5	1.8	2.1	2.4	3.0	3.6	4.8	6.0
Head rounding radiusR₂, max		0.8	1.0	1.2	1.4	1.6	2.0	2.5	3.2	4.0
Thread length b	extended	-	18	19	20	22	25	28	34	40
	normal	10	11	12	13	14	16	18	22	26

Table 2, mm

Screw lengthl	Nominal thread diameter d
	2	2.5	3	3.5	4	5	6	8	10
3				-	-	-	-	-	-
4						-	-	-	-
5						-	-	-	-
6							-	-	-
8								-	-
10									-
12
14
16
(18)				Standard lengths
20	-
(22)	-
25	-
(28)	-	-
30	-	-
35	-	-
40	-	-
45	-	-
50	-	-
55	-	-
60	-	-
65	-	-
70	-	-

Notes:

1. Screw lengths given in brackets are not recommended for use.
2. The extended thread length is preferred.
3. Screws with a shank length less than the thread length, including the incomplete thread run-out, shall be manufactured with thread along the entire length of the shank.

*For screws machined by cutting; not specified in other cases.

Example of a designation for a rounded-off pan-head screw, product grade A, thread diameter d=8 mm, coarse thread pitch, thread tolerance class 6g, length l=50 mm, normal thread length b=22 mm, property class 4.8, plain:

Screw A.M8 - 6g´50.48 GOST 11644-75

The same, product grade B, fine thread pitch, extended thread length b=34 mm:

Screw B.M8´1 - 6g´50 - 34.48 GOST 11644-75

Thread — per GOST 24705-81. Thread run-out and incomplete thread — per GOST 10549-80.

Recesses — per GOST 24669-81.

Radius under head — per GOST 24670-81.

Tolerances, methods for inspection of dimensions and deviations in form and position of surfaces — per GOST 1759.1-82.

Surface defects and inspection methods — per GOST 1759.2-82.

The diameter of the plain part d₁ shall be equal to the outer diameter of the thread or equal to the shank diameter for rolling metric thread per GOST 19256-73.

Technical requirements — per GOST 1759.0-87.

The theoretical mass of the screws is given in the appendix.

Appendix (informative). Theoretical mass of screws

Screw length l, mm	Mass of 1000 pcs of steel screws with coarse thread pitch, kg ≈ at nominal thread diameterd, mm
	2	2.5	3	3.5	4	5	6	8	10
3	0.134	0.250	0.415	-	-	-	-	-	-
4	0.152	0.280	0.459	0.671	1.004	-	-	-	-
5	0.171	0.310	0.503	0.730	1.081	-	-	-	-
6	0.190	0.340	0.547	0.790	1.159	2.131	-	-	-
8	0.227	0.400	0.635	0.909	1.314	2.378	3.764	-	-
10	0.264	0.460	0.723	1.029	1.469	2.625	4.117	8.996	-
12	0.302	0.520	0.811	1.148	1.624	2.873	4.470	9.633	17.50
14	0.351	0.595	0.900	1.267	1.779	3.120	4.822	10.27	18.50
16	0.395	0.665	1.016	1.385	1.934	3.367	5.175	10.91	19.50
18	0.439	0.735	1.118	1.506	2.144	3.615	5.528	11.54	20.49
20	-	0.805	1.220	1.625	2.327	3.947	5.881	12.18	21.50
22	-	0.874	1.322	1.744	2.509	4.237	6.233	12.82	22.50
25	-	0.979	1.476	1.923	2.783	4.672	7.004	13.77	24.01
28	-	-	1.630	2.102	3.057	5.107	7.775	14.72	25.52
30	-	-	1.731	2.221	3.240	5.397	8.059	15.83	26.52
35	-	-	1.987	2.520	3.697	6.121	9.113	17.72	29.84
40	-	-	2.242	2.818	4.153	6.846	10.17	19.60	32.80
45	-	-	2.498	3.116	4.610	7.571	11.22	21.48	35.75
50	-	-	2.754	3.414	5.067	8.296	12.28	23.37	38.71
55	-	-	3.009	3.712	5.523	9.020	13.33	25.25	41.67
60	-	-	3.265	4.011	5.980	9.745	14.39	27.14	44.63
65	-	-	3.520	4.309	6.437	10.47	15.44	29.02	47.59
70	-	-	3.776	4.607	6.894	11.19	16.49	30.90	50.55

Note. To determine the mass of screws made from other materials, the mass values given in the table shall be multiplied by a factor of: 0.356 for aluminium alloy; 1.08 for brass.