GOST 23360-78 Parallel Keys

GOST 23360-78 applies to key joints with parallel keys and establishes dimensions and tolerances for parallel keys and the corresponding keyways on shafts and in hubs.

The standard fully complies with ST SEV 189-79 and corresponds to ISO/R 773-69 recommendation.

Dimensions of keys and their tolerances shall conform to those shown in Fig.1 and Table 1.

Fig. 1

Table 1

mm

Width b (tolerance h9)	Height h (tolerance h11; h9)	Chamfer size s or radius r		Length l (tolerance h14)
		max	min	from	to
2	2			6	20
3	3	0.25	0.16	6	36
4	4			8	45
5	5			10	56
6	6	0.40	0.25	14	70
7	7			16	63
8	7			18	90
10	8			22	110
12	8			28	140
14	9	0.60	0.40	36	160
16	10			45	180
18	11			50	200
20	12			56	220
22	14			63	250
24	14	0.80	0.60
25	14			70	280
28	16			80	320
32	18			90	360
36	20			100	400
40	22			100	400
45	25	1.20	1.00	110	450
50	28			125	500
56	32			140	500
63	32	2.00	1.60	160	500
70	36			180	500
80	40			200	500
90	45	3.00	2.50	220	500
100	50			250	500

Notes:

1. For keys with a height from 2 to 6 mm, the height tolerance corresponds to h9.

2. Keys with lengths outside the specified length ranges are permitted. Lengths over 500 mm shall be selected from the Ra20 series per GOST 6636-69.

3. The smallest chamfer s and radius r are given for critical key joints.

4. At the customer’s request, keys with a height from 2 to 6 mm may be manufactured with tolerances to h11.

5. Keys 7×7 mm and 24×14 mm may only be used for mounting cutting tools.

Example of designation for a Type 1 key with dimensions b=18 mm, h=11 mm, l=100 mm:

Key 18×11×100 GOST 23360-78

Same, for design 2:

Key 2-18×11×100 GOST 23360-78

Key lengths shall be selected from the series: 6; 8; 10; 12; 14; 16; 18; 20; 22; 25; 28; 32; 36; 40; 45; 50; 56; 63; 70; 80; 90; 100; 110; 125; 140; 160; 180; 200; 220; 250; 280; 320; 360; 400; 450-500 mm.

Material — cold-drawn steel for keys to GOST 8787-68. Other steel with a tensile strength of at least 590 MPa (60 kgf/mm) may be used.

Dimensions of keyway cross-sections and their tolerances shall conform to those shown in Fig.2 and Table 2.

Keyways of shaft and hub

Fig. 2

Note. The working drawing shall indicate one dimension for the shaft, t₁ (preferred option), or d-t₁, and for the hub, d+t₂.

Table 2

mm

Shaft diameter d	Key cross-section b*h	Keyway
		Width b					Depth				Radius of curvature r₁ or chamfer s₁×45°
		Free fit		Normal fit		Close fit	Shaft t₁		Hub t₂
		Shaft (H9)	Hub (D10)	Shaft (N9)	Hub Js	Shaft and hub (P9)	Nom.	Limit deviation	Nom.	Limit deviation	Max	Min
From 6 to 8	2×2	+0.025 0	+0.060 +0.020	-0.004 -0.029	+0.012 -0.012	-0.006 -0.031	1.2		1.0
Over 8 to 10	3×3						1.8		1.4		0.16	0.08
Over 10 to 12	4×4						2.5	+0.1 0	1.8	+0.1 0
” 12 ” 17	5×5	+0.030 0	+0.078 +0.030	0 -0.030	+0.015 -0.015	-0.012 -0.042	3.0		2.3
” 17 ” 22	6×6						3.5		2.8		0.25	0.16
Over 22 to 30	7×7; 8×7	+0.036 0	+0.098 +0.040	0 -0.036	+0.018 -0.018	-0.015 -0.051	4.0		3.3
” 30 ” 38	10×8						5.0		3.3
Over 38 to 44	12×8						5.0		3.3
” 44 ” 50	14×9	+0.043 0	+0.120 +0.050	0 - 0.043	+0.021 -0.021	-0.018 -0.061	5.5		3.8		0.4	0.25
” 50 ” 58	16×10						6.0	+0.2 0	4.3	+0.2 0
” 58 ” 65	18×11						7.0		4.4
Over 65 to 75	20×12						7.5		4.9
” 75 ” 85	22×14						9.0		5.4
” 85 ” 95	24×14; 25×14	+0.052 0	+0.149 +0.065	0 -0.052	+0.026 -0.026	-0.022 -0.074	9.0		5.4		0.6	0.4
” 95 ” 110	28×16						10.0		6.4
Over 110 to 130	32×18						11.0		7.4
” 130 ” 150	36×20	+0.062 0	+0.180 +0.080	0 -0.062	+0.031 -0.031	-0.026 -0.088	12.0		8.4
” 150 ” 170	40×22						13.0		9.4
” 170 ” 200	45×25						15.0		10.4		1.0	0.7
” 200 ” 230	50×28						17.0	+0.3 0	11.4	+0.3 0
Over 230 to 260	56×32	+0.074 0	+0.220 +0.100	0 -0.074	+0.037 -0.037	-0.032 -0.106	20.0		12.4
” 260 ” 290	63×32						20.0		12, 4		1.6	1.2
Over 290 to 330	70×36	+0.074 0	+0.220 +0.100	0 -0.074	+0.037 -0.037	-0.032 -0.106	22.0		14.4
” 330 ” 380	80×40						25.0		15.4
Over 380 to 440	90×45	+0.087 0	+0.260 +0.120	0 -0.087	+0.043 -0.043	-0.037 -0.124	28.0		17.4		2.5	2.0
” 440 ” 500	100×50						31.0		19.5

Notes:

1. Any combinations of tolerance zones specified in Table 2 are permitted for the width of the shaft and hub keyway.

2. For heat-treated parts, a tolerance of H11 for the shaft keyway width is permitted, provided this does not affect the functionality of the joint.

3. In critical key joints, the junction of the keyway bottom with the side walls shall be made with a radius, the value and tolerances of which shall be specified on the working drawing.

4. In justified cases (hollow and stepped shafts, transmission of reduced torques, etc.), smaller cross-section sizes of standard keys may be used on shafts of larger diameters, except for shaft extension ends.

When checking dimensions d-t¹ and d+t², tolerances shall conform to those specified in Table 3.

Table 3

mm

Key height	Dimensional tolerances
	d-t₁	d+t₂
From 2 to 6	0 -0.1	+0.1 0
Over 6 to 18	0 -0.2	+0.2 0
Over 18 to 50	0 -0.3	+0.3 0

Tolerances for the shaft keyway length shall conform to tolerance zone H15.

The theoretical mass of keys is given in Appendix 1.

Inspection of keyway dimensions and their location relative to the corresponding cylindrical surfaces — to GOST 24109-80 — GOST 24118-80, GOST 24120-80 and GOST 24121-80.

For products designed before January 1, 1980, the tolerances for key joint dimensions given in Appendix 3 are permitted.

Surface roughness parameters of key joint elements are given in Appendix 2.

APPENDIX 1

For reference

Theoretical mass of keys

Dimensions in mm

b	2	3	4	5	6	7	8
h	2	3	4	5	6	7	7
l	Theoretical mass of 1000 Type 2 keys, kg
6	0.188	0.423
8	0.251	0.565	1.01
10	0.314	0.707	1.26	1.95
12	0.377	0.848	1.51	2.35
14	0.440	0.989	1.76	2.75	3.94
16	0.502	1.13	2.01	3.14	4, 52	6.15
18	0.565	1.27	2.26	3.53	5.09	6.92	7.93
20	0.628	1.41	2.51	3.92	5.65	7.69	8.80
22		1.55	2.76	4.32	6.22	8.46	9.67
25		1.77	3.14	4.91	7.07	9.62	11.0
28		1.98	3.52	5.50	7.91	10.77	12.3
32		2.25	4.02	6.28	9.01	12.31	14.1
36		2.53	4.52	7.06	10.2	13, 85	15.8
40			4.99	7.85	11.3	15.38	17.6
45			5.62	8.83	12.7	17.31	19.8
50				9.75	11.1	19.23	22.0
56				10.9	15.8	21.54	24.6
63					17.7	24.23	27.7
70					19.6	26.82	30.8
80						30.77	34.9
90
100
110
125
140
160
180
200
220
250
280
320
360
400
450
500
For Type 1, the mass is reduced by	0.013	0.045	0.108	0 ,241	0.364	0.58	0.76
For Type 3, the mass is reduced by	0.006	0.022	0.054	0.120	0.182	0.29	0.38

Continued

Dimensions in mm

b	10	12	14	16	18	20	22	24
h	8	8	9	10	11	12	14	14
l	Theoretical mass of 1000 Type 2 keys, kg
6
8
10
12
14
16
18
20
22	13.8
25	15.7
28	17.6	21.1
32	20.1	24.1
36	22.6	27.1	35.6
40	25.1	30.1	39.6
45	28.3	33.9	44.5	56.5
50	31.4	37.7	49.5	62.8	77.7
56	35.2	42.2	55.4	70.2	86.8	104.9
63	39.4	47.4	62.5	78.9	97.9	119	151	166
70	44.0	52.8	69.2	88.0	109	132	168	184
80	50.2	60.3	79.1	100	124	151	192	211
90	56.5	67.8	89.0	113	140	170	216	237
100	62.4	75.4	98.9	126	155	188	240	263
110	68.6	82.9	109	138	171	207	264	290
125		93.6	123	157	194	235	300	329
140		104.8	138	176	218	264	336	369
160			157	201	249	301	384	422
180				226	280	339	432	475
200					311	377	480	527
220						414	528	580
250							600	659
280
320
360
400
450
500
For Type 1, the mass is reduced by	1.35	1.94	2.97	4.31	6.00	8.09	11.2	13.6
For Type 3, the mass is reduced by	0.67	0.97	1.48	2.15	3.00	4.04	5.6	6.8

Continued

Dimensions in mm

b	25	28	32	36	40	45
l	14	16	18	20	22	25
h	Theoretical mass of 1000 Type 2 keys, kg
6
8
10
12
14
16
18
20
22
25
28
32
36
40
45
50
56
63
70	191	246
80		281	361
90	246	317	407	508
100	273	352	452	565	691
110	300	392	502	622	760	968
125	341	441	567	705	864	1100
140	382	492	632	795	967	1240
160	437	562	722	905	1105	1410
180	491	632	812	1015	1240	1590
200	546	703	904	1130	1380	1770
220	600	773	994	1240	1520	1940
250	682	883	1130	1410	1730	2210
280	764	983	1134	1580	1930	2470
320		1125	1447	1806	2171	2781
360			1627	2036	2452	3135
400				2261	2760	3530
450						3971
500
For Type 1, the mass is reduced by	15.1	21.1	31.1	43.7	59.3	85.3
For Type 3, the mass is reduced by	7.5	10.5	15.5	21.8	29.6	42.6

Continued

Dimensions in mm

b	50	56	63	70	80	90	100
h	28	32	32	36	40	45	50
l	Theoretical mass of 1000 Type 2 keys, kg
6
8
10
12
14
16
18
20
22
25
28
32
36
40
45
50
56
63
70
80
90
100
110
125	1375
140	1540	1957
160	1760	2236	2516
180	1980	2516	2830	3560
200	2200	2795	3145	3950	5020
220	2420	3075	3459	4352	5520	6990
250	2750	3494	3932	4950	6280	7948	9810
280	3080	3914	4403	5539	7030	8900	10950
320	3459	4473	5032	6229	7909	10011	12359
360	3901	5032	5661	7023	8918	11286	13934
400	4400	5591	6290	7910	10040	12720	15700
450	4950	6290	7066	8902	11300	14300	17660
500	5500	6989	7862	9890	12560	15890	19625
For Type 1, the mass is reduced by	118	164	208	297	430	614	842
For Type 3, the mass is reduced by	59	82	104	148.5	215	307	421

APPENDIX 2

Recommended

Dependence of surface roughness parameters on dimensional tolerance

Dimensional tolerance by grade	Nominal dimensions
	Up to 18	Over 18 to 50	Over 50 to 120	Over 120 to 500
	Ra, µm, max
IT9	3.2	3.2	6.3	6.3
IT10	3.2	6.3	6.3	6.3
IT11	6.3	6.3	12.5	12.5
IT12, 13	12.5	12.5	25	25
IT14, 15	12.5	25	50	50

Notes:

1. Roughness parameters of surfaces with unspecified tolerances — 20 µm.

2. The roughness parameter of the keyway bottom is recommended to be taken as 6.3 µm.

APPENDIX 3

For reference

Tolerances for key and keyway dimensions shall conform to: for key height h — Ba (OST 1024); for shaft keyway depth t¹ and hub depth t² — A⁵ (OST 1015); for parallel key length t — B⁷ (OST 1010 and GOST 2689-54); for shaft keyway length for parallel key — A⁸ (OST 1010).

Tolerances for key and keyway dimensions on shafts and in hubs (boss) for width b shall conform to those specified in Tables 1 and 2.

Table 1

Type of joint	Dimensional tolerances			Purpose of fits
	key	shaft keyway	hub keyway
Fixed tight fit on shaft, sliding fit in hub			B₃	For single-unit and batch production (general engineering)
Fixed tight fit on shaft, running fit in hub	X₃	PSh	A₃	For mass production (automotive industry)
Fixed snug fit on shaft, running fit in hub	PSh₁		A₃	For guide keys

Table 2

Nominal width of key and keyway, mm	Tolerances of shaft and hub groove dimensions, µm
	PSh		PSh₁
	upper	lower	upper	lower
From 1 to 3	-10	-50	+55	+10
Over 3 to 6	-10	-55	+65	+15
” 6 ” 10	-15	-65	+75	+20
” 10 ” 18	-20	-75	+85	+25
” 18 ” 30	-25	-90	+100	+30
” 30 ” 50	-32	-105	+120	+35
” 50 ” 80	-40	-125	+140	+40
” 80 ” 120	-50	-150	+160	+45

Corresponds to DIN 6885.