BRITISHSTANDARD
46 : Part 1 : 1958
CONFIRMEDOCTOBER
1985
KEYS AND KEYWAYS
@
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BRITISH STANDARD SPECIFICATION
KEYS AND
KEYWAYS
B.S. 46 : Part 1 : 1958 Incorporating amendments issued May 1959 (PD 3375), January 1%1 and January 1964 (PD 5124)
CONFIRMEDOCTOBER
(PD 4022)
1985
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B.S. 46 : Part 1 : 1958
THIS BRITISHSTANDARD, having been approved by the Mechanical Engineering Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council on 30th May, 1958. First published (as B.S. 46), September, 1909. First revision (as B.S. 46, Part l), October, 1924. Second revision, April, 1929. Third revision, February, 1953. Fourth revision, May. 1958. The Institution desires to call attention to the fact that this British Standard does not purport to include all the necessary provisions of a contract.
.
.
In Order to keep abreast of Progressin the industries concerned, British Standards are subject to periodical review. Suggestions for improvements will be recorded and in due Course brought to the notice of the committees charged with the revision of the Standards to which they refer. A complete list of British Standards, numbering over 9,000,
fully indexed and with a note of the contents of each, will be found in the BSI Catalogue whichmaybe purchased from BSI Sales Department. The Catalogue may be consulted in many public libraries and similar institutions. This Standard makes reference to the followingBritish Standards : B.S. 308. Engineering drawing practice. B.S. 350. Conversion factors and tables. B.S. 970. Wrought steels. B.S. 1916. Limits and fits for engineering. British Standards arerevised, when necessary, by the issue either of amendment Slips or of revised editions. It is important that Users of British Standards should ascertain that they are in possession of the latest amenainents or editions.
T h e following B.S.I. references relate to the work on this Standard :Committee referenus, MEE/4. MEE/4/4 Draft Tor cornrnent CX(MEE) 6855
2
B.S. 46 :Part 1 : 1958
CO-OPERATING ORGAMZATIONS The Mechanical Engineering IndustryStandardsCommittee, under whose supervisionthis British Standard was prepared. consistsofrepresentativesfromthe following Government departments and scientific and industrial organizations :*Admiralty Air Ministry Associated Officers' Technical Committee Association of Consulting Engineers (Incorporated) British Chemical Plant Manufacturers' Association British Compressed Air Society *British Electrical and Allied Manufacturers' Association *British Engineers' Association *British Gear Manufacturers' Association *British Internal Combustion Engine Manufacturers' Association *British Iron and Steel Federation British Railways, The British Transport Commission Crown Agents for Oversea Governments and Administrations *D.S.I.R.-Mechanical Engineering Research Laboratory Electricity Council, the Generating Board and Area Boards in England and Wales *Engineering Equipment Users' Association Gas Council *High Commission of India Institdte of Marine Engineers Institute of Petroleum Institution of Civil Engineers Institution of Gas Engineen InstitJtion of Heating and Ventilating Engineers *Institution of Mechanical Engineers Institution of Mechanical Engineers (Automobile Division) *Institution of Production Engineers *Locomotive and Allied Manufacturers' Association of Great Britain Machine Tool Trades Association Ministry of Labour and National Service (Factory Inspectorate) Ministry of Power *Ministry of Supply Ministry of Trcnsport and Civil Aviation Ministry of Works National Coal Board National Physical Laboratory (D.S.I.R.) Radio Industry Council War Office Theorganizationsmarked with anasterisk in theabove list. togetherwiththe following. were directly represented on the Committee entrusted with the preparation of this Standard :Association of Crane Makers Bright Steel Bar Association British Cycle and Motor Cycle Industries' Association British Internal Combustion Engine Research Association British Shipbuilding Research Association Gauge and Tool Makers' Association Institution of Engineers and Shipbuilders in Scotland Keyrnakers' Association Milling Cutter and Reamer Association North East Coast Institution of Engineen and Shipbuilders Society of British Aircraft Constructon Steelworks Plant Association Tapcr Pin Manufacturers' Association
3
B.S. 46 : Part 1 : 1958
CONTENTS Page Co-Operating organizations
3
Foreword
6
0
SPECIFICATION 1.
SOPe
7
2. Materials
8
3. The application of keys and keyways
a. Parallel keys b. Taper keys C. Tangential keys keys d. Woodruff
8
8 9 9
4. Dimensions and tolerancea of parallel and
taper keys and keyways
0
9
5. Dimensions and toleranw of ‘Woodruff keys and keyways 10 6. Dimensions of tangential keys and
keyways
24
7. Dimensions of keys and keyways for 26
marine tailshafts
8. Keys and keyways for tapcrcd shaft ends 28
TAB= 1. Rectangular parallel keys, keyways and
keybars
12
2. Square parallel keys, keyways and keybars 14
3. Rectangular tapcr keys and keyways, gib-hcad or plain
0
16
4. Square taperkeys and keyways, gib-head
or plain
18
5. Woodruff keys and keyways
20
6. Comparison of Woodruf€ key numbers (Whitney, British and Amrican)
22
4
0
B.S. 46 : Part 1 : 1958 TABLES-ontinued. Page keys7. Tangential
25
8. Rectangular parallel keys for marine
tailshafts
26
9. Preferred lengths of plain keys, rectangular
or square section, parallel or taper
30
10. Preferred lengths of gib-head keys
rectangular or square section
31
APPENDICES
units
A. Preferred lengths of keys
29
B. Approximateequivalents of metricand inch
32
5
B.$. 46 : Part 1 : 1958 BRITISH STANDARD FOR
KEYS AND KEYWAYS FOREWORD Thestandardization ofkeys and keywayswasfirstconsidered by the Engineering Standards Committee (the original name and form of the present B.S.I.). As a result Standard Specification No. 46, dealing only in with rectangular parallel keys, keybars and keyways,waspublished 1909.
In subsequent revisions, other types of keys wereadded to theStandard and Parts 2 and 3 of B.S. 46 were prepared for parallel splines and taper pins respectively. Parts 2 and 3 have since been further revised and Part 2 has been published as B.S. 2059. This revision of B.S. 46, Part 1 for Keys and keyways has been prepared under the authority of7’he Mechanical Engineering Industry Standards Committee in response to requests for larger manufacturing tolerances. The various types of keys and keyways now have consistent dimensions and tolerances for each size as b r as possible, and this will enable a Standard range of Cutters to be used for the machining of the various types of keyways. The increased tolerances recommended in this Standard may entail more fittingof keys into keyways than was envisaged in the 1953 edition. This is inevitable with an increase in tolerance on the keys and keyways. Carefulconsiderationhas been given to various requests for increases in tolerances and also for decreases in tolerances but the Committee have come to the conclusion that the tolersnces now given are those most acceptable to industry at the present time. The Committee responsible for this revision of B.S. 46, Part 1, gave earnest consideration to the specification of limits and fits to B.S. 1916 for the keys and keyways specified. It was decided not to introduce these limits and fits as the key and keyway Standard does not represent finished articles for prescribed conditions of assembly. It recommends dimensions and tolerances from which required fits can be obtained by fitting to meet most design requirements. The Committee wasinfluenced in reaching this decision by the absence of a Standard range of Cutters for machining to B.S. 1916 and the non-availability of keybar to these limits at the time the revision of this Standard was being prepared. This decision will be reviewed in the light of circumstances existing when further revision is contemplated. The principle of the dimensions and tolerances recommended is to provide for each key to be retained in the shaft rather more securely than in the mating hub but this can be varied to meetSpecial applications within the dimensional limits recommended in this Standard.
6
B.S. 46 : Part 1 : 1958
0
The tables of preferred key lengths given in Appendix A havebeen revised to conform withpresent-day requirements andthe key sizes have been brought into accord with tables 1, 2, 3 and 4. Whilst the details of radii and charnfers are not a mandatory Part of this specification the recomrnendations shown are in graduated steps of nominal value instead of by formulae, as with the forrnulae of former issues a Special Cutter radius was required for each size of keyway. Each radius recomrnended now applies to a range of keyway sizes. Owing to the difficulties of obtaining keybar in thirty-seconds of inch, keys formerly of these sizes have been replaced by those which are more readilyavailable. Minor changes in the range of shaft sizeshave been made to accornmodate this. The revised table for -keys and keyways for marine tailshafts has been compiled by the British Shipbuilding Research Association from a survey of thc current practice of British shipbuilding and marine engineering firms and frorn theoretical and experimental studies. Thc table of Woodruff keys and keyways has been extended into the range of snlaller sizes to rneet requirements for instrument and similar purposes. To facilitate the changeover to the recomrnended Woodruff key designation as shown in Table 5 , the obsolete key and Cutter nurnbers have been given in Table 6 . The notes relating to keys and keyways for tapered shaft ends have been retained unaltered. A requirement has been stated for tangential keys and the Type A tangential keyof the 1929 issue of B.S. 46 has beenreinsertedin this revision. SPECIFICATION SCOPE
1. This British Standard relates to the following : n. Rectangular parallel keys and keyways.
b. Square parallel keys and keyways. C. Rectangular taper keys and keyways, piain and gib-head. (1. Square taper keys and keyways, plain and gib-head. e . Woodruff keys and keyways. f : Tangential keys and keyways. ,L'. Keys and keyways for marine tailshafts. 11. Keys and keyways for tapered shaft ends. Decimal values in the tables have been rounded off to three significant figures. NOTE.Thisspecification is based on British units. For theconvenience of users approxirnate equivalents in metricunitsaregiven in Appendix B. More accurate conversions should he obtained from the tables in B.S. 350 ' Conversion factors and tablcs.'
7
B.S. 46 : Part 1 : 1958 MATERIALS
2. a. Keys and keybarcomplying
AI altered
/UR.. I964
with Tables 1 to 7 of this British Standard shall be manufactured from steel to En 6A, En 8 or En 9 of B.S. 970, ' Wrought Steels,' and those complying with Table 8 from steel to En 4 or En 5. It is recommended that En 6A and En 8 steels should be cold drawn for keys in sections up to 2 in. square and hot rolled (En 8 in condition NGC 1 (Normalized)) for larger sections, and that En 9 steek should not be cold drawn for keys of sections larger than % in. Square. b. Bright keybar is not normally available in sections over 1 % in. THE APPLICATION OP KEYS AND
I
M
3
KEYWAYS
3. As it is not possible to foresee the combination of design considerations for any given application, the selection of the proper type of key must rest with the design authority. The following are general recommendations for use when circumstances permit and when keying is preferred to other methods of transmitting torque (e.g. splines). U. Purullel keys. For use for transmitting unidirectional torques on transmissions not subject to heavy starti,.g loadsand where periodic withdrawal or sliding of the hub memkr may be required. In many instanccs, particularly couplings, a gib-head cannot be accommodated, and therc is insufficient room to drift out the key from behind. In these c8sts it is necessary to withdraw thecomponent over the key and a parallel key is essential. Parallel square and rcctangularkeys are normally side fitting with top clearance and are usually retained in the shaft rather more securely than in the hub. (i) Rectungulur. The general purpost key for shafts greater than 1 in. diametcr. (ii) S q w e . For use with shafts up to and including 1 in. diameter or for shafts upto 6 in. diamcter where it is desirable to have a greater key depth than is provided by rectangular keys. In cases of stepped shafts the larger diameters an usually required by considerations other than torque e.g. resistancc to bending. Where components such as fans, gears, impcllers etc., are attached to thc larger shaft diameter, the usc of a key d e r than Standard for that diametcr may bc permissible. As this results in u n q u a l disposition of the key in the shaft and its related hub the dimcnsions H and h must be recalculated to maintain thc T/2 relationship. b. Tuper keys. For transmitting hcavy unidirectional, rcversing or vibrating torques and in applications where periodic withdrawal ofthe key may bc a nccessity. For transmitting unidircctional torquts taper keys arc top fitting. but may be top and side fittingw k r e For transmitting rcversing or vibratory torques taper keys may be top
rcquircd. 8
B.S. 46 : Part 1 : 1958
and side fitting where required. In this case the keyway in the hub should have the Same width value as the keywayin the shaft (Le., Columns 8 and 9 of Tables 3 and 4). Taper keys cannot be used in applications requiring a sliding hub member. (i) RecrangularundSquare. Taper keys of rectangular section are for general purposes and are of less depth than square keys. Taper keys of square section are for usewith shafts up to and including 1 in. diameter or for shafts up to 6 in. diameter where it is desirable to have greater key depth. (ii) Gib-hend. Gib-heads are provided to facilitate the withdrawal of keys. (iii) Pluirr. Where little or no protuberance is permissible. Tangential ~ P Y S .For the transmission of reversing torque, usually under conditions of heavy loading. C.
d. Woodruj'keys. For light applications, or angular location of associated parts on tapered shaft ends. These keys are not recommended for other applications, but if so used Corner radii in the shaft and hub keyways are advisable to reduce stress concentration. DIMENSIONS AND TOLERANCES OF PARALLEL A N D TAPER KEYS AND KEYWAYS
4. The dimensions and tolerances for key and keywaywidthsgivenin Tables I , 2, 3 and 4 are based on the width of the key W and provide a fitting allowance. The fitting allowance is designed to permit an inter-
ferencebetween the key and the shaft keyway anda slightly easier condition between the key and the hub keyway. The maxirnum and minimum values in Tables 1, 2, 3 and 4 are based 011 the following : Width ofkey and keybar, W = Nominal size with a plus tolerance. Width of keyway in shaft, W, = Nominal size with a minus tolerance. Width of keyway in hub, W h = Nominal size with a plus tolerance. Minimumwidth of key = Maximum width ofkeywayin shaft. a. Parallel keys und keyways. (i) The dimensions and tolerances for side-fitting keys of rectangular parallel section. and for the appropriate keybar and keyways shall be as given in Table 1. (ii) The dimensions and tolerances for side-fittingkeysof square parallel section and for the appropriate keybar and keyways shall be as given in Table 2. b. Taper keys und keywap. (i) The dimensions and tolerances for taper keys of rectangular section with or without gib-heads shall be as given in Table 3. (Seealso Clause 36). 9
B.S. 46 : Part 1 : 1958 (ii) The dimensions and tolerances for taper keys of square section with or without gib-heads shall be as given in Table 4. (See also Clause 3h). (iii) The basic taper for all taper keys and keyways in hubs shall be 1 in 100. C. DeptJz o f k e y w u p . The depth of the keyway shall be obtained by measuring from the circumference of the shaft diametrically opposite, or from the bore of the hub to the root of the keyway along the centre line diametrically opposite and shall not be measured from the sideCorner. The method of dimensioning keywaysin shafts and hubs on drawings should conform to the recommendations of B.S. 308, ' Engineering drawing practice.' To obtain the dimensions for recording on the drawing, the keyway depths and tolerances shall be applied to the basic shaft diameter.
d. Radii und chanrfers. Corner radii are recommended for keyways, as Stress concentration in Corners may lead to failure. Keys and keybar are not normally chamfered or radiused in the condition as supplied, but this may be done atthe time of fitting. or, by arrangement between the purchaser and the manufacturer, during manufacture. Radiiand chamfers are shown as nominal values in columns of Tables 1,2,3 and 4. The chamfer on the key should in each case be of the minimum value to clear the actual radius in the keyway. NOTE. In the case of shrink and heavy force fits i t may be found necessary to depart from the width and depth tolerances laid down for keys and keyways. Any Variationin the width of keyway rnust be such that the greatest width is at the end from which the key enters. Any Variation in the depth of keyway rnustbe such that the greatest depth is at the end from which the key enters. Any Variation in the thickness of the key must be such that the greatest thickness U at the end from which the key is driven.
This specification d e s not take account of misalignment and or ofiset greater than that provided for in the size tolerance. i n the case of shrink and heavy force fits, true alignment must be ensured. DIMENSIONSANDTOLERANCES
OP WOODRUFF KEYS AND KEYWAYS
5. The dimensions and limits of tolerances for British Standard Woodruff keys and keyways shall be as shown in Table 5. Provision is made in Table 5 for an optional alternative design of WoodrufF key which difTers
from the normal form in its depth as shown at H in the Sketch and Table. a. The designation of Woodruf key numbers. The following system is applied to Woodruff keys and Woodruff keyCutters. The British and American designations are identical. Each key is designated by three or more significant digits. The last two digits give the nominal diameter in eighths of an inch. The digit or digits preceding the last two give the nominal width (thickness) in thirty-seconds of an inch 10
0
B.S. 46 : Part 1 : 1958 Thus No. 204 refers to a key z i X~ ','a in., or 1 6 in. thick X 4/2 in. diameter, similarly, 1210 refers to a key ' % 2 X " ' 8 in., or ?6 in. thick X 1 % in. diameter.
b. Depth of keywuy. The depth of a Woodruif keyway shall be measured along the centre line from theperipherv of the shaft, or the circumference of the hub bore, to the root of the keyway. The depth of the keyway in a tapered shaft shali be measured normal to the shaft surface. (This is illustrated in B.S. 308, ' Engineering drawing practice '). NOTE ON KEYSL AFSR OHG RAEFRT S The sizes of shafts shown in Tables 1, 2, 3 and 4 of this Standard are those for which the respective types of keys are considered to be normallyappropriate. For larger shafts, it is considered that tangential keys, multiple keys or splines would be rnore appropriate. However. if it is decided to useSingle parallel keys on shafts larger than those considered normal for such keys in this Standard,the following formulae niay be applied to establish (nominal) values related to the shaftdiameter ' d '. (For the purposes of the tables, ' d ' is the diarneter of the largest shaft for each key size i.e. ' d ' corresponds to column 2 of the tables. For intermediate shaft diameters or shaft diarneters larger than those of the tables, H should, of Course. be calculated frorn (iii), using for ' d * the nominal shaft diameter.) d (i) Key width W = 4 (ii) Key thickness T
or
d
=gfor =
d
T for
Tables 1 and 3 Tables 2 and 4
(In Tables 1 and 3, T has in some sizes been rounded off to maintain the inch fractional sizes.) T d (iii) Keyway depth in shaft H =T +T - W'
4:
+
(iv) For parallel keys, keyway depth in hub h = (T - H) X where X is a clearance such that X min. = H min. h min. - T max. X max. = H max. $- h max. - T min. The incremental Pattern by which the tolerances (and clearance X) increase with shaft size may be Seen from a n inspection of the tables, but it should be noted that a Point will be reached at which any further increase in tolerance (with increase in shaft size) would be neither necessary in manufacture nor acceptable in use.
+
11
AE 1964
TABU 1. RECTANGULAR PARALLEL KEYS, KEYWAYS AND KEYBARS
?i
i
Over
1 1% 1%
I
0
0
--
.- -.-. -.
I
2%'
W
oddrd
Ja., JPM
.~
. . .
~
j
1
1
~
~
i
~
!
!
i
1
3% 4 5
0.8770.875 0.629 10.625 0.874 0-875 0-370 0.376 ' 0.875 I 0.876 0.264 0-270 0-062 D.877 0.8750.629 0-625 1.0031.000 0.7540.750 0.999 1-ooO 0,441 0.447 ' 1.00~ i 1-001 0-318 0.324 0.062 1.003 1 O .O O 0.754 0.750 1.248 1.250 0-518 0.524 1.253 1-250 0.8790.875 0.366 0-372 0.062 1.253 1.250 0-879 0.875 1.250 1.252
5 7
6 7 8
1.006 1.000 1.498 1.500 0-599 0.605 1.m 1-502 0.4120.418 1.5041.500 1.748 1.750 0.740 0.7461.7501.752 1.754 1-750 1.2561.250 0.5260.532 2,0052.000 1.3811.375 1.998 2.000 0.818 0-824 2.000 2-002 0.5730.579
8 9
9 10
10
11
2.248 2-250 0.897 0.905 2.2502.252 2.2552.250 1.5061.500 0.619 0 627 0.125 2.498 2.500 0.975 0.983 2-500 2.502 0-666 0-674 0.187 1.631 1.625 2.505 2.500 2.7552.750 1.881 1.875 2.748 2.750 1.114 1.122 2.7502.752 0.187 0.7770.785
11 12 13
12 13 14
3.0063.000 3.2563.250 3.5063.500
2.0082.000 2.1332.125 2.3832.375
14 15 16
15 16 17
3.7563.750 4.0084.000 4.2584.250
3.748 3-750 1,492 1-502 3-750 3.752 1.0261 1.036 2.5082.500 2.6332.625 3.998 4.000 1.571 1.581I 4.000 4.002 2-883 2.875 4.248 4.250 1.711 1.721 4.250, 4.252
17 18 19
18 19 20
4.5084.500 4.7584.750 5.008 5-000
Aa
.
3 3% 4
6
n
3
..
0.499 0.500 i 0.190 0.196 ' 0.500 0.501 0.131 10.137 0.020 0.502 0.500 ! 0.315 0.312 0.441 0.438 0.624 0.625 0.260 0.266 i 0.625 0.626 0.185 j 0.191 0.020 0-627 0.625 0.441 0.438 I 0.503 0.500 0.749 I 0*750,0.299 0.305 ! 0.750 j 0.751 0.209 0.215 Oa20 0.752 0 750 0.503 0.500
0-502 0.500 0.3150.312 0.6270.625 0.7520.750
.. . I
~
1
1
~
!
0.062 0.125 0.125
1400 ~.
Bright keybar is not normally available in sections larger than the above.
2.998 3.000 1.195 1.203 3*000 3.002 0.8230.831 0.187 3.248 3.250 1.273 1.281 3.2503.252 0-187 0.8700.878 3.498 3.500 1.413 1.4213-50013.502 0.980 0.988 0.250
i
1 1
~
1
0.250 0.250 0.312
1
4.498 4.500 1.791 1.801 4.5004.502 1.229 1.239 0.312 I 4.750 1 1.868 4.748 1.8784.7504.752 1.277 1 1.287 0.312 i 4.998 5.000 2.010 2.020 5.000 5.002 1.3851.395 0.312
1
iI 2-
c 'NOTE. The koy chunfer thall be the minimum to cleu the keywry ndius. Nomlnrl values ~ f given. For largor shafts see the note following Clruse 5.
1
W
V,
%: .. a
..
L
L
OL
TABLE 2. SQUARE PARALLELKEYS,KEYWAYS KEYBARS
L
P
t
AND
All dlmensions are in inchts
Ilf
3
Over
u p to and ncluding
--
~
7
1
8
'
9
!
Keyway h shaft Key size
I
6 ~. -~ -.
Diameter of Shaft -
iWidth W aad Thickwss T __-~
W xT
Max.
Width WS
_ _- .I Min.
Depth H
Max.
Min.
,I
I-
; Bright keybar
~
__ '
Nominal
-
~
___
..
Min.
- __
Keyway in hub
Max.
Min.
Max.
hlin.
- __-
- __
. ..-.
?4 ?4 1
0.127 0.125 0-124 0.125 0.072 0.078 0.125 0-126 0.190 0.188 0.187 0.188 0.107 0.113 0.188 0.189 0.252 0.250 0.249 0.250 0.142 0.148 0.250 0.251 0.115
1% 1% 1%
' 0.312 0.010 ' 0.377 0.375 0.020 , 0.440 0.438 I 0.020 0.502 0.500
2 2% 3
0.314 0.312 0.311 0-312 0.177 0.183 0.312 0.313 0.142 0.377 0.375 0-374 0.375 0.213 0.219 0.375 0.376 0.169 0.175 0.440 0.438 0.437 0.438 0.248 0.254 0.438 0.439 0-197 0.203 0.230 II 0.502 0-500 0.499 0.500 0.283 0.289 0.500 0501 0.224 0.627 0.625 0.624 0.625 0.354 0.360 0.625 0.626 0.278 0.284 0.752 0.750 0-749 0.750 0.424 0.430 0-750 0.751 0.333 0.339
3% 4 5
0.877 0.875 0-874 0.875 0-495 0.501 0.875 0876 0.387 0-393 1.003 1.OOO 0.999 1.OOO 0-566 0.572 1.OoO 1.001 0.442 0.448 1.253 1.250 1.248 1.250 0.707 0.713 1-250 1.252 0.551 0.557
0.062 0.062 0.062
0.125 0.188
0.250
1 ~
~
6
~
-
1
-- - - -
0.020
0.627 0.625 0.020 0.752 0.750 ~
1.504 1*500 1.498 1.500 0.848 0.854 1.500 1.502 0.661 0.667
.. e
W ul Q)
B.S.46 : Part
1 : 1958
TABLE 3. RECTANGULAR TAPER KEYS
tA-tD! I
0
,
1
L" 1 f
t a p e r I in 100 on t h i s f a c e t
Basic,
T i Gib-head key
All dimensions
Section at deep end of keyway in hub 3
Key size
~~~
Max. ~
3 3%
3%
~
4
,
5
4 5
6
1%7 6 7
8 9 10 11
8
9 10
11
7/e
'
'
12
,
Y
5/8
1 X % 1%X 7/a 1% X 1 X 1% 2 X 1% 2% X 1% 2% X 1% 2% X 1%
3
X2
~
Min.
-.~
~~
Max. : Min. ~~
0.249 0.314 0-312 0.254 0.249 0.377 0.375 0.254 0.440 0.438 0.316 ' 0.311 0.502 0.500 0.316 0.311 0.627 0.625 0.442 0.437 0-752 0.750 0.504 0.499 0.877 0.875 ' 0.630 0-624 1.003 1-OOO' 0755 0 749 1.253 1.250 0.880 0.874 1.007 1.504 1.500 0.999 1.754 1.750 1.257 ' 1.249 2.005 2000 ' 1.382 1.374 2.255 , 2.250 1.509 1.499 2.505 2.500 1.634 1.624 2.755 , 2.750 1.884 1.874 3.006 ' 3.000 ' 2.014 1-999
~
~~
~
Min.
Max.
Mo. ~
~
~
Max. ~
.~
0-311 0.312 ! 0-3120.313 0.3740.375 1 0.375 0.376 0.437 I 0.438 0.4380.439 0.499 0-500 ' 0.500 0.501 0.624 ' 0.6250.6250.626 0.749- 0.750 0.750 0.751 0.87< 0.875 0.875 0.8'16 . Oo 1.000 1.001 0.999 1O 1.248 1.250 1.250 1,252 1.498 1.500 1.500 1.502 1.748 1.750 1.750 1.752 1.998 2*000 2400 2.002 2.250 2.252 2.248 1 2.250 2.498 2.500 2.500 2.502 2.748 2.750 2.750 2.752 2.998 ' 3.000 3.000 3.002 ~
NOTE. *Th(: k y chamfer ßhall be the minimum to clear the keyway radius. Nominal values shall 16
0
BS. 46 :Part 1 :1958 A N D KEYWAYS, GIB-HEAD
O R PLAIN
R
Basic taper Iin
'
(
R
100 on this f a c e t
1
AI dtered
May.
Alternativedesign showing a parallel extension with a drilled hole to facilitate extraction Plain taper key
t See B.S. 308--'Engineering drawing practice' for explanation of dimsnrioning tapen.
Depth in hub at deep end of keyway h
Depth in shaft H -
Mia
_--
I
-1--
~~
Max.
--
- ..-
Min.
~
,
~
~
0-599 0.605
0.384
0.740 0.746 0.818 0.824 0.897 0.905 0.975 ' 0.983 1.114 1.122 1.1951.203 1
0.493 0.539 0.581 0.628 0.738 0-782
~
1
~
Gibbead . .. .
B
~ . .
0.096 0.092
0-010 0.010
0.118
0.020 0.020 0.020
0.114 0.168
0.191 0.245 0.299 0.346 0.390 0-499 0.545 0.589 0.636 0.746 0-790
.-
~
Max. ~.
---
0.146 0-152 0.090 I 0.150 0.156 0.086 0.186 0.192 0.112 0.190 ' 0.196 0.108 0.260 0-266 0.162 0.299 0.305 0.185 0-370 0.376 0.239 0.441 0.447 0.293 0.518 0.524 0.340
Nominal 1 keyway : radius j andkey I_cbamfer r* 1
0.020 0.062 0.062 0.062
0-062 0.125 0.125 0.125 0.187 0.187 0-187
be given. For plain keys Columns 17 to 21 do not apply.
17
i
i
C
I
1959
B.S. 46 : Part 1 : 1958 TABLE 4. SQUARE TAPER KEYS AND
L--A --/+D4 Basic
/
t a p e r I in 100 on this f a c e t
-
f T
t Gib-head key
t-
/
Section at deep end in of keyway hub
/' r l
I
All dimensions
Z ~
Diameter of shaft
,
I
Key size
I1
-
--..___-
Keyway in shaft Width WS ~.
-.
1
Keyway in hub
,
1 _Width Wh _ _ ~ ~
Max. Mia. j Max. ____ ~
Min. 0-124 1 0-125 1 0.125 0-126 0.18710.188 0.1880.189 0.249 0.250 0.2500.251 ~
~
1
%6
X
5/16
NOTE. *The key chamfer shall be
~
0.3140.3120.316
! 0.311 0.3110.312 0.3740.375
1
~
~
'
0.312 ' 0.313 0.3750.376
the minimum to clear the kcyway radius. Nominal values ar18
0
B.S. 46 : Part 1 : 1958 KEYWAYS, GIB-HEAD OR PLAIN
Basic taper I in 100 on this f a c e t
r
I ,
4
'
1
!
I
'
Alternative design showing a parallel extension wlth a drilled. hole to facilitate extractlon Plain taper key
0
t See B.S. 3Ol-'Engineering are in inches
1
12 -~ __
13 -.
-
shaft aod hub _____
1
14
I
drawing practicc' for explanation of dimensioning tapers.
15
16
Nominrl
I
D e & i 1 atDepth in hub deep end of keyway h
ehaft H
Mo. I, Max. 0.072 j 0.078
0.283 1 0.354 1 0.424 0-495 0.566 I 0.707 0.848 I ~
~
I
Min.
i
-
I
i-
Max.
1-----1--
0.039 j 0.045
0.289 0.202 i 0.360 I 0.256 0.430 ' 0.310 I 0.501 ' 0.364 i 0.572 1 0.418 i 0.713 0.526 i 0.854 1 0-635
1
1
Gibbcid
kemy rndius Pnd Leg chamfer r*
~
1
0.010 0.010 0.010 0.010 0.010 0.020 0.020 0.020 0.020 0.062
0.208 0.262 0.316 0.370 0.424 OX62 0.5320.062 0.641 0462
1
1
D
0.1 0.2 0-2
1
1946
1x6
given. For plain keys Columns 17 to 21 d o not apply.
19
-i
0.3 0-3 0.4 0.4 0.5 0.5 0.6 0-6 0.7 0.7
..
B.S. 46 : Part 1 : 1958
TABLE 5. WOODRUFF
0
All dimensiona ara I
1 ~
.
..-.
2- ___/- -.3
4 1 5
. .
~
Nominal fractional size of key
KeY and cutter No.
i
- 1i
304
1I
Width
1
I-
Dia.
204 i 404
305 405 505 406 506 606 507 607 807 608 808
i
i
I
1008 609 809 1009
810 1010 1210 1011 1211 812 1012 1212
8
/
9
Diameter of key
Depth of key
Ihickness of key
A
B
C
I
403
203 303
~~______
5/16
i I
I ~
j I
Max.
Mio.
Max.,
0.375 0.370 0-375 0-370 .-Oe375 0.370 0.490 0.490 0.490 0.615 0.615 0.615 0.750 0.740 0.750 0.740 0.750 0.740 0.875 0.865 0.875 0.865 0.875 0.865 l*OOO 0.990 1.OOO 0.990 1 W O 0.990 1.125 1.115 1.125 1.115 1.125 1.115 1.250 1.240 1.250 1.240 1.250 1.240 1.375 1.365 1.375 1.365 1.500 1.490 1.490 i 1.490
-
Min.
0.166 0.166 0-166 0.198 0.198 0.203 0.198 0.250 0-245 0.250 0-245 0.250 0.245 0.313 0.308 0-313 0.308 0.313 0.308 0.375 0.370 0.375 0.370 0-375 0.370 0.4-3 0.433 0.438 0-433 0-438 0.433 0.484 0.479 0-484 0.479 0.484 0.479 0.547 0-542 0.547 0.542 0-547 0-542 0.594 0.589 0.594- 0.589 0.641 0.636 0.641 0.636 0.641 10.636 0.171 0.171 0.171 0-203 0.203
Max.
0.063
-1
0-095 0.126 0.063
0.095 0.126 0.095 0-126 0.157 0.126 0.157 0.189 0-157 0.189 0.251 0.189 0.251 0.313 0.189 0.251 0.313 0.251 0-313 0-376 0.313 0.376 0.251 0.313 0.376
-- -
Width of keyway in shaft D __
Min.
..-
.
~~
Min.
Max.
___
0.062 0.061 0.063 0.094 0.093 0.095 0.125 0.124 0.126 0.062 0.061 0.063 0.094 0-093 0-095 0.125 0-124 0.126 0.094 0493 0.095 0.125 0.124 0-126 0.156 0.155 0.157 0.125 0.124 0.126 0.156 0.155 0.157 0.188 0.187 0.189 0.156 0.155 0.157 0.188 0.187 0.189 0.250 0.249 0-251 0.188 0.187 0.189 0.250 0.249 0.251 0.312 0-311 0.313 0.188 0.187 0.189 0-250 0.249 0.251 0.312 0.311 1 0.313 0-250 0.249 0.251 0.312 0.311 0.313 0-375 0.374 0.376 0-312 0.311 0-313 0.375 0.374 1 0.376 0.250 0.249 0.251 0.312 0.311 I 0.313 0.375 0.374I 0.376 ~
~
~
~
NOTE. For details of obsolete Woodruff key and cutter numbem referena lould be made to
20
0
B.S. 46 : Part 1 : 1958
LRadius
0.005
o.olo
OptionalDesign
given in inches
1
12
13
14
1
i: 1 16
15
-_
T
17
_.
Depth 01k e m y
Width 01keyway ln hub or boss
Depth of keyray in shaft
in hub at e n t r e line
E
P
G
MlU.
Mln.
____
___-
0-063 0.095 0-126 0.063 0.095 0.126 0.095 0.126 0-157 0.126 0.157 0.189 0.157 0-189 0.251
0.189 0.251 0.313 0.251 0.313 0.376 0.313 0.376 0.251 0.313 0.376
i
0.065 0.097 0.128 0.065 0-097 0.128 0.097 0-128 0.159 0.12% 0.159 0.191 0.159 0.191 0.253 0.191 0.253 0.315 0.191 0.253 0.315 0.253 0.315 0.378 0.315 0.378 0.253 0.315 0-378
Min.
Mal.
Min.
0.135 0.119 0.104 0.167 0.151 0.136 0-198 0.182 0.167 0-246 0.230 0.214 0-292 0.276 0.245 0-339 0.308 0.277 0.385 0.354 0.323 0.417 0.386 0.354 0.433 0.402 0.511
0.140 0.124 0.109 0.172 0.156 0-141 0.203 0.187 0.172 0.251 0.235 0.219 0-297 0.281 0.250 0-344 0.313 0.282 0.390 0-359 0-328 0.422 0.391 0.359 0.438 0.407 0.516
0.480
0485
0.448
0-453
0.042 0.057 0.073 0.042 0-057 0.073 0-057 0.073 0.089 0.073 0.089 0.104 0.089 0.104 0.136 0.104 0.136 0.167 0.104 0.136 0.167 0.136 0.167 0-198 0-167 0-198 0.136 0-167 0.198
__- __ ___ -
Tab!e 6.
21
Depth 01key (optioaal design)
-~
Dime* sioa J
____-
Max.
Max.
Min.
0.047 0.062 0.078 0.047 0.062 0.078 0-062 0.078 0.094 0.078 0.094 0.109 0.094 0.109 0.141 0.109 0.141 0.172 0.109 0.141 0.172 0.141 0.172 0.203 0-172 0.203 0.141 0-172 0-203
0.162 0.162 0.162 0.194 0.194 0.194 0.240 0.240 0-240 0.303 0.303 0-303 0.365 0.365 0.365 0.428 0.428 0-428 0.475 0.475 0.475 0.537 0.537 0.537 0.584 0.584 0.631 0-631 0.631
0-156 0.156 0-156 0188 0.188 0.188 0.234 0.234 0.234 0.297 0.297 0.297 0.359 0.359 0.359 0.422 0.422 0.422 0.469 0.469 0.469 0.531 0-531 0-531 0.578 0.578 0.625 0.625 0.625
___
20
19
___.-
H ~
.
1I
18
NOUI. 5/64 364 %4 764 964
964
Xe
f10 f10 3-56 3-56
Xe
416 ?46
Xe
?46
X6
?46 5/64 764 5/64 5/64 5/64 764
342
Y52 7/64
-764
764
B.S. 46 : Part 1 : 1958
TABLE 6. COMPARISON OF WOODRUFF KEY NUMBERS (WHITNEY, BRITISH AND AMERICAN) NOTE. This table has been prepared for reference, to help readers to substitute the new numbers (column 4) for the obsolete numbers given in columns 1. 2 and 3. It is stronglyrecommended thatthe obsolete numben should besuperseded by the key and Cutter numbers designated in Table 5 of the Specification. 1
2
4
5
British Standard key and Cutter number and American Cutter oumber
Width :thicLaess) C
3
Britisb Original Britisb Standard Standard Wtwp Cutter Cutter and key numbe~ number key nmnber (obsolete) (obsolete)
211 212 213
-
203 303 403
1 2 3
1 2 3
204 304 404
4 5 6
4 5 6
305 405
505
-
-
7
406
8
506
9 91 10
9 10
606
11 12
-
11
607
A
A
807
13 14 15
-
13
608
15
808
B
B
-
1008
152 141 16 17 18
-
16
609
18
809
C
-
C
1009
61 7 8
161
19
-
507
-
-
22
6
B.S. 46 : Part 1 : 1958 2
1
British I Standard key numbe (obsolete)
4
6 i k e of key
British Standard key and cutter number and Amerlcan Cutter aumber
20 21 D E
22 23
F 24 25 G 126 127
128 129 26 27 28 29
Rx
sx
Tx ux
vx R
S T U
V 30 31
32 33 34 35 36
23
Diameter A
B.S. 46 : Part 1 : 1958 DLMENSIONS OP TANGENTIAL KEYS AND KEYWAYS
0
6. Thedirncnsions of tangentialkeysandkeywaysshall be as given in Table 7. The width of the key (W) is 350 (0.3) of the diameter of the shaft, in which case the thickness of the key (T) becomes ?40 (0.1) of the diameter of the shaft. Tangential keys should be provided with an extra length for driving. This should not be less than the width of the pair of keys.
0
0
24
0
B.S. 46 : Part 1 : 1958
PABLE 7. TANGENTIAL KEYS in. rad on kcywayr
1
t
Tapcr 1 in 100
Peralkl asscmbled width
3/32
in. chamftr a t 4S0on k
-
All dimeosions m in inches I
-
Dia-
Dt-
of sb.ft
Df Ib.ft
meter
m e t a
D
D
4 4% 4%
10%
4% 5 5%
11 11% 12
24 25
5% 5%
27
6
12% 13 13%
6% 6% 6%
14 14% 15
30 31 32
7 7% 8
16 17
33 34 35
8%
19 20
21
9% 10
22 23
26 28 29
18
9
36
-
I
Theabove dimemions are based on theformulae W = 0.3D and T = 0-1Dbut for an intermediate diameter of shaft the key section shall bc the same as that for the next size larger shaft in the above List. 25
B.S. 46 : Part 1 : 1958 DIMENSIONS OP KEYS AND KEYWAYS POR MARINE TAILSHAPTS
7. a. General. The dimensions of keys and keyways for marine tailshafts shall be as shown in Table 8 and Fig. 2. NOTE. The dimensionsof keys formarine diameters obtained by Lloyd's rule.
tail-shafts should behased
on shaft
b. Depth at forward end. The keyway in the tailshaft shall be produced
in such a manner that, at the forward end of the keyway, the total depth at the side is half the thickness of the key. C. Position on shaft. The Position of the keyway in the shaft and its relation to the Position of the propeller boss shall be as shown in Fig. 4. d. Pul1 up on taper. After the propeller nut has been tightened by hand the propeller shall be pulled up on the shaft taper fora distance of 0.006 in. per inch of shaft diameterif the shaft taper is 1 in 12 and 0-008in. per inch of shaft diameter if the shaft taper is 1 in 16. e. Sealing arrangements. Sealing arrangements at the forward and after ends of the propeller boss shall be sufficient to prevent ingress of corrosive materials to the tail-shaft under all conditions of Service.
TABLE 8. RECTANGULAR PARALLEL KEYS FOR MARINE TAILSHARS (All dimensions are given in inches) Nominal diameter of shaft at after end On parallel portion under liner D
I Nominal dimensions of key
llrickness
Width W
T
inclusive 6 to 6% 7 to 7% 8 to 8% 9 to 9% 10 to 10% 11 to 11% 12 to 12% 13 to 13% 14 to 14% 15 to 15% 16 to 16% 17 to 17% 18 to 18% 19.to 19% 20 to 20% 21 to 21% 22 to 22% 23 to 23% 24 to 24% 25 to 2 5% 26 to 2 6% 27 to 27% 28 to 28% 29 to 30
26
Fillet radius in keyway and chamfer On key R
B.S. 46 : Part 1 : 1958
I
cutter
Type 1. Sled runner key (preferred method)
Liner
______-------
I
lllllllll!lll
Tailshdf t
I
Type 2. Rognd ended keyuay (alternative method)
Fig. 2. Types of key and Position of keyway in shaft
27
B.S.46 : Part 1 : 1958 KEYS AND KEYWAYS FOR TAPERED SHAFI’ ENDS
8. U. Shufi tupers. The taper on the diameter of the shaft shall be one of those listed below :
Where a self-releasing taper is required. Generallyused for locomotive Piston rods, etc. DieselenginefuelinjectionPumps. Popular in automobile practice ; usedby the Society of Motor Manufacturers and Tradersandthe Society of Automotive Engineers (American). : General taper of decimalform.
1 in 3.428 : I in 4 : 1 in 5 : 1 in 8 :
1 in 10 I in 12 and 1 in 16
}
: Alternatives used for marine shafting.
6. Keywuys. The keyway shall lie parallel to the side of the cone.
As a result of the Change of section of the shaft along the cone, the depth of keyway at the sides will not be constant. This is illustrated diagrammatically in Fig. 1. (B.S. 308, ‘ Engineering drawing practice,’ Shows the recommendedmethodofdimensioningkeywaysin tapered shaft ends).
‘prgc h a l l diamcttr Fig. 1. Variation in keyway depth in taper shaft ’\,
/
/
diamtttr
Width of key. Height of key side at large end of taper. HS = Height of key side at small end of taper. K L = Depth of keyway at large end of taper. KS Depth ef keyway at small end of taper. NOTE. KL decreases to KS, and HL increases 10 HS as the diameter ot thz shatt diminishes. W
HL
= =
-
C. Dimensions und toferunces. For the purpose of detenniningthe correct size of key, the nominal diameter of the shaft shall be that of the iarger end of the cone. Except in the case of marine tail shaft applications, the dimensions and tolerances of the keys and keyways for coned shafts shall be as shown in Table 1 for keys and keyways of rectangular section, Table 2 for keys and keyways of Squaresection andTable 5 for Woodruffkeys and keyways .
28
B.S. 46 : Part I : 1958 APPENDIX A
PREFERREDLENGTHS OF KEYS The details of the availability and preferred lengths of plain and gibheadkeys,which are givenin Tables 9 and 10, havebeencompiled following an investigation of manufacturing records and are included for reference purposes. Ir should be noted that no lengths are included for a number of the key sizes which appear in Tables 1, 2, 3 and 4, the reason h i n g that such keys are not normally stocked, and are supplied to customer’s requirements.
29
B.S. 46 : Part 1 : 1958
TABLE 9. PREFERRED LENGTHS OF PLAINKEYS, RECTANGULAR OR SQUARE SECTION, PARALLEL OR TAPER
1
n All dimensions are in inches
T
Overall length L
1
%
I
3i
‘/ 4
3
i?4 4
1
- -
X X X
X
X
X
X
X
X
X
X
X
s
X
X
X
X
X
X
X
X
X
X
X
r;
X
X
X
X
X
X
X
X
X
X
X
X
N
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
not generally stocked butare I
NOTE. Larger sizes than those given in this table are manufactured to customcr’s individual requirements.
30
B.S. 46 : Part 1 : 1958 TABLE 10. PREFERRED LENGTHS OF GIB-HEAD KEYS RECTANGULAR OR SQUARE SECTION
T
L------
t
L
, m ------4 Lw4
All dimensions are in inches Overall length L
1
:
~
NOTE. Larger or smaller sizes than those given in this table are not generally stocked butare manufactured to customer's individual requirements.
31
B.S. 46 : Part 1 : 1958
APPENDIX B APPROXIMATE EQUIVALENTS OF METRIC AND INCH UNITS
T
Inches
Inches
mm Fractional
%4
%2
364
?4s
Fractional
Decimal
0.001 0-002 0.003
0.025 0.051 0.076
0.004 0.005 0.006
0.102 0.127 0.152
0.007 0.008 0.009
0.178 0.203 0.229
0.010 0.015 6 0.0200
0.254 0.397 0.508
0.030 0.031 3 0-040
0.762 0.794 1.016
0.046 9 0.050 0.060
1.191 1.27 1.524
0.062 5
1.588 1.778 1.984
0.070 964
0.078 1
2.286
%n
0-080 0.090 0.093 8
0.100 0.109 4 0.110
2.54 2.78 2-79
0.120 0.125
3.05 3-18
764
M
0.130
3.30
0.140 0.140 6 0.150
3.56 3.57 3-81
0-1563 0.160 0-170
3.97 4.06 4.32
0.171 9 0.180 0.187 5
4.36
0.190 0.200 0.203 1
2.032 2.381
32
mm
Decimal
4.76
5-08 5-16
5.56
0.218 8 0-2344 0.250
5-95 6-35
0-2656 0.2813 0.296 9
6.75 7.14 7.54
0.300 0.312 5 0.375
7.62 7.94 9.53
0.400 0.437 5 0.500
10-16 11.11 12.70
0.5625 0.600 0-625
14.29 15.24 15.88
06875
1746
B.S. 46 :Part 1 : 1958 D IC k mm
mm Fractional
W 'X6 76
'X6 1
Decimal
Fractional
Deetmpl
0.700 0.750
17-78 19.05
24 25
610 635
0.800 0.812 5 0.875
20.32 20.64 22.23
26 27 28
660
686 711
0.900
22.86 23-81 25.4
29 30 31
737 762 787
50.8
32 33 34
838 864
35 36
889 914
0-9375 1.00 2 3 4 5
6 7
76.2 101.6 127 152 178
8 9 10
229
11 12 13
279 305 330
14 15 16
356
17 18 19
432 457
20 21 22
508 533 559
W
584
203 254
381 406
483
33
813
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9104-6-0.2k-B
