GOST 24071-97 Woodruff Keys and Keyways

Foreword

1 Developed by Technical Committee TC 258 “Gears and Structural Elements of Machine Parts”.

Submitted by Gosstandart of Russia.

2 Adopted by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 12-97 dated November 21, 1997).

The following voted in favor of adoption:

Name of state	Name of national standardization body
Republic of Tajikistan	Tajikgosstandart
Republic of Armenia	Armgosstandart
Republic of Belarus	Gosstandart of Belarus
Republic of Kazakhstan	Gosstandart of the Republic of Kazakhstan
Kyrgyz Republic	Kyrgyzstandart
Republic of Moldova	Moldovastandart
Russian Federation	Gosstandart of Russia
Republic of Uzbekistan	Uzgosstandart
Ukraine	Gosstandart of Ukraine

3 This standard is the complete authentic text of ISO 3912-77 “Woodruff Keys and Keyways” and contains additional requirements reflecting the needs of the national economy.

4 By Decree of the State Committee of the Russian Federation for Standardization and Metrology No. 409-st dated November 17, 1999, the interstate standard GOST 24071-97 (ISO 3912-77) was put into effect directly as the national standard of the Russian Federation on July 1, 2000.

5 Supersedes GOST 24071-80.

Informational data

Referenced regulatory and technical documents

Designation of the referenced regulatory document	Clause number
GOST 8786-68	A.1
GOST 24109-80	A.8
GOST 24110-80
GOST 24111-80
GOST 24115-80
GOST 24116-80
GOST 24117-80
GOST 24119-80
GOST 24120-80
OST 1015	B.1
OST 1024
OST 1025

1 Purpose

This standard establishes the dimensions and tolerances of Woodruff keys and the corresponding keyways in shafts and hubs, as well as the relationship between shaft diameter and key cross-section for torque transmission and positional fixing.

Additional requirements reflecting the needs of the national economy are given in Appendices A, B, C and D.

The requirements of the standard and Appendix A are mandatory.

2 Field of application

This standard applies to general-purpose cylindrical shafts and cylindrical shaft ends.

3 Dimensions and tolerances of keys

The dimensions and tolerances of keys are given in Figure 1 and Table 1.

* Applied by agreement of the interested parties.

**h²=0.8h¹ (the value may be rounded to 0.1 mm).

Figure 1

Table 1

mm

b		h¹		D		s
Nom.	Tol. h9*	Nom.	Tol. h11	Nom.	Tol. h12	min	max
1.0	-0.025	1.4	-0.060	4	-0.120	0.16	0.25
1.5		2.6		7	-0.150
2.0		2.6		7
2.0		3.7	-0.075	10
2.5		3.7		10
3.0		5.0		13	-0.180
3.0		6.5	-0.090	16
4.0	-0.030	6.5		16		0.25	0.40
4.0		7.5		19	-0.210
5.0		6.5		16	-0.180
5.0		7.5		19	-0.210
5.0		9.0		22
6.0		9.0		22
6.0		10.0		25
8.0	-0.036	11.0	-0.110	28		0.40	0.60
10.0		13.0		32	-0.250
* A different tolerance may be adopted by agreement of the interested parties.

4 Material

Material - steel with a tensile strength of not less than 590 N/mm² after final treatment (unless otherwise agreed between the interested parties).

5 Shape, dimensions and tolerances of keyways

The dimensions and tolerances of keyways are given in Figure 2 and Table 2.

Figure 2

Table 2

mm

	Width b				Depth
	Nom.	Tolerances			Shaft t¹		Hub t²		Radius R
Dimensions of normal- or low-form keys		Normal fit		Close fit
		Shaft N9	Hub Js9	Shaft and hub P9	Nom.	Limit deviation	Nom.	Limit deviation	max	min
1.0×1.4×4	1.0	-0.004; -0.029	±0.012	-0.006; -0.031	1.0	+0.1	0.6	+0.1	0.16	0.08
1.5×2.6×7	1.5				2.0		0.8		0.16	0.08
2.0×2.6×7	2.0				1.8		1.0		0.16	0.08
2.0×3.7×10	2.0				2.9		1.0		0.16	0.08
2.5×3.7×10	2.5				2.7		1.2		0.16	0.08
3.0×5.0×13	3.0				3.8	+0.2	1.4		0.16	0.08
3.0×6.5×16	3.0				5.3		1.4		0.16	0.08
4.0×6.5×16	4.0	-0.030	±0.015	-0.012; -0.042	5.0		1.8		0.25	0.16
4.0×7.5×19	4.0				6.0		1.8		0.25	0.16
5.0×6.5×16	5.0				4.5		2.3		0.25	0.16
5.0×7.5×19	5.0				5.5		2.3		0.25	0.16
5.0×9.0×22	5.0				7.0	+0.3	2.3		0.25	0.16
6.0×9.0×22	6.0				6.5		2.8		0.25	0.25
6.0×10.0×25	6.0				7.5		2.8	+0.2	0.25	0.16
8.0×11.0×28	8.0	-0.036	±0.018	-0.015; -0.051	8.0		3.3		0.40	0.25
10.0×13.0×32	10.0				10.0		3.3		0.40	0.25

6 Relationship between shaft diameter and key dimensions

Table 3 gives two series of relationships between shaft diameter and key size: series 1 - for torque transmission, series 2 - for positional fixing of parts (with a fixed fit, where torque transmission is achieved by friction).

Table 3 - Dependence of shaft diameter on key size

Shaft diameter d, mm				Key size, mm, normal form or equivalent low form
Series 1		Series 2
Over	Up to	Over	Up to
3	4	3	4	1.0×1.4×4
4	5	4	6	1.5×2.6×7
5	6	6	8	2.0×2.6×7
6	7	8	10	2.0×3.7×10
7	8	10	12	2.5×3.7×10
8	10	12	15	3.0×5.0×13
10	12	15	18	3.0×6.5×16
12	14	18	20	4.0×6.5×16
14	16	20	22	4.0×7.5×19
16	18	22	25	5.0×6.5×16
18	20	25	28	5.0×7.5×19
20	22	28	32	5.0×9.0×22
22	25	32	36	6.0×9.0×22
25	28	36	40	6.0×10.0×25
28	32	40	-	8.0×11.0×28
32	38	-	-	10.0×13.0×32

7 Designation

The designation of a key indicates its width, height and the standard designation.

Examples:

Designation of a normal-form key with cross-section b×h¹=5×6.5 mm:

Key 5×6.5 GOST 24071-97

Designation of a low-form key with cross-section b×h²=5×5.2:

Key 5×5.2 GOST 24071-97

Appendix A (mandatory)

Additional requirements reflecting the needs of the national economy

A.1 This standard does not apply to joints designed before this standard came into effect, nor to keyed joints assembled by fitting or selection of keys.

A.2 Key material - bright-drawn steel for Woodruff keys to GOST 8786-68 or to Section 4.

A.3 In technically justified cases (hollow and stepped shafts, transmission of reduced torques, etc.), it is permitted to use smaller key cross-sections than specified in Table 2 for shafts of larger diameters, except for shaft output ends.

A.4 For non-critical joints, it is permitted to make the junction of the keyway bottom with the side walls as a 45° chamfer equal to radius R.

A.5 A free fit of the key with the shaft and hub is permitted. The tolerances for the free-fit keyway width b must correspond to the tolerance zones: H9 for the shaft, D10 for the hub.

A.6 Any combinations of tolerance zones specified in Table 2 are permitted for the keyway width b of the shaft and hub.

A.7 For heat-treated parts, tolerance limits of the shaft keyway width corresponding to tolerance zone H11, and of the hub keyway width - D10, are permitted.

A.8 Inspection of keyway dimensions and their location relative to the corresponding cylindrical surfaces shall be carried out in accordance with GOST 24109 - GOST 24111; GOST 24115 - GOST 24117; GOST 24119; GOST 24120.

A.9 Series 2 (Table 3) may also be used for non-critical joints (transmitting low torques at low rotational speeds that do not affect the service life of the parts; short-term operation of the joint, etc.).

A.10 Depending on the machining and measurement datum adopted, the working drawing may show, instead of t¹, the nominal size for the shaft d-t¹ with the tolerance limit for t¹ per Table 2, and for the hub, instead of t², the size d-t² with the tolerance limit for t² per Table 2.

A.11 The mass of keys is given in Annex B.

A.12 For products designed before 01.01.80, the tolerance limits of keyed joint dimensions given in Annex C are permitted.

A.13 Surface roughness parameters of keyed joint elements are given in Annex D.

Annex B (informative)

Theoretical mass of 1000 normal-form keys

Table B.1

Key size	Mass of 1000 keys, kg
1.0×1.4×4	0.031
1.5×2.6×7	0.152
2.0×2.6×7	0.204
2.0×3.7×10	0.414
2.5x3.7x10	0.510
3.0×5.0×13	1.050
3.0×6.5×16	1.600
4.0×6.5x16	2.120
4.0×7.5×19	3.240
5.0×6.5×16	2.680
5.0×7.5×19	4.040
5.0×9.0×22	5.660
6.0×9.0×22	6.780
6.0×10.0×25	8.480
8.0×11.0×28	13.800
10.0×13.0×32	24.100

Annex C (informative)

Tolerance limits of keyed joint dimensions for products designed before 01.01.80

C.1 Tolerances for key and keyway dimensions:

for key height h¹ - B⁴ OST 1024;

for the depth of the shaft keyway t¹ and the hub keyway t² - A⁵ OST 1015;

for the diameter of the segment key D - B⁵ OST 1025;

for the diameter of the shaft keyway for a segment key, with a plus deviation from the nominal - no more than 8% of the key diameter.

C.2 Tolerance limits of the dimensions of keys and keyways in shafts and hubs with respect to width b shall comply with those given in Tables C.1 and C.2.

Table C.1

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

Table C.2

	Tolerance limit of shaft and hub keyway dimensions, µm
Nominal width of key and keyway, mm	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 6888 and ISO 3912.