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BSW
/ BSF/ WHITWORTH THREAD SERIES
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| APPLICATION |
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Applications
in imperial systems where clearance between male and female
threads is required to be controlled.
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| SPECIFICATION |
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Basic
Dimensions : B.S. 84-1956
Gauging Practice : B.S. 919 Part II - 1971
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| DIAMETER
– TPI COMBINATION BSW
Series. |
|
Dia
Inch
|
Dia
MM
|
TPI
|
|
1/8"
|
3.175
|
40
|
|
3/16"
|
4.7625
|
24
|
|
¼"
|
6.35
|
20
|
|
5/16"
|
7.9375
|
18
|
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3/8"
|
9.525
|
16
|
|
7/16"
|
11.1125
|
14
|
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½"
|
12.700
|
12
|
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*9/16"
|
14.2875
|
12
|
|
5/8"
|
15.875
|
11
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*11/16"
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17.4625
|
11
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¾"
|
19.05
|
10
|
|
7/8"
|
22.225
|
9
|
|
Dia
Inch
|
Dia
MM
|
TPI
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1"
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25.400
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8
|
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1.1/8"
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28.575
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7
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1.1/4"
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31.750
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7
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1.1/2"
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38.1
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6
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1.3/4"
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44.450
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5
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2"
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50.8
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4.5
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2.1/4"
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57.15
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4
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2.1/2"
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63.50
|
4
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2.3/4"
|
69.850
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3.5
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3"
|
76.200
|
3.5
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*3.1/4"
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82.550
|
3.25
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3.1/2"
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88.900
|
3.25
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*3.3/4"
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95.250
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3
|
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4"
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101.60
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3
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4.1/2"
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114.30
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2.875
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5"
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127.000
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2.75
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5.1/2"
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139.70
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2.625
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6"
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152.40
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2.5
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| DIAMETER
– TPI COMBINATION BSF
Series |
|
Dia
Inch
|
Dia
MM
|
TPI
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|
*#
3/16"
|
4.7625
|
32
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*
7/32"
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5.5563
|
28
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¼"
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6.35
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26
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*9/32
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7.1438
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26
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5/16"
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7.9375
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22
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3/8"
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9.525
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20
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7/16"
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11.1125
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18
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½"
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12.700
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16
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9/16"
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14.2875
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16
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5/8"
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15.875
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14
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*11/16"
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17.4625
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14
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¾"
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19.05
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12
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7/8"
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22.225
|
11
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1"
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25.400
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10
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1.1/8"
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28.575
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9
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1.1/4"
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31.750
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9
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*1.3/8"
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34.925
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8
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Dia
Inch
|
Dia
MM
|
TPI
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|
1.1/2"
|
38.1
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8
|
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*1.5/8"
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41.275
|
8
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1.3/4"
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44.450
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7
|
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2"
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50.8
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7
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2.1/4"
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57.15
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6
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2.1/2"
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63.50
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6
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2.3/4"
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69.850
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6
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3"
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76.200
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5
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3.1/4"
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82.550
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5
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3.1/2"
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88.900
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4.5
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3.3/4"
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95.250
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4.5
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4"
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101.60
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4.5
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4.1/4"
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114.30
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4
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For
any other diameter pitch combination not covered under
BSW & BSF series, use WHITS like e.g. 1" – 12 Whits
(M).
For
Whitworth gauges with diameter in mm use designation,
like W30-12 (M)
Note:
To be dispensed with wherever possible.
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| CLASS
OF FIT |
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For
Plugs - Medium Class (M) & Normal Class (N), Close
Class (C )
For Rings – Close Class (C), Medium Class (M) &
Free Class (F)
Only above classes are recommended as per specification
and no other classes should be used.
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| FORM
OF THREAD |
|
The
included thread angle for Whitworth is 55 degree and
the threads are fullform for GO gauge, i.e. we have
to maintain minor diameter for plug gauges and major
diameter in case of ring gauges and radius at crest
and root of threads as per the specification.
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|
COATED
& UNCOATED THREADS
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|
Type
|
Before
Coating
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After
coating/
Uncoated finish threads
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Internal
threads
(Plug gauges)
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Over
Size by 0.001"/ 0.025mm
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Medium,
Normal Class
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External
threads
(Ring gauges)
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Under
size by 0.001"/0.025mm
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Close,
Medium, Free class.
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| DESIGNATION
/ MARKING SYSTEM |
7/8"
-9 BSW (N)
1" -10 BSF (C )
½" -16 BSF (F)
1.1/2" -16 Whits (M)
W30 -16 (M) |
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