BSW (British Standard Whitworth) A coarse thread devised and standardised at Manchester in 1841 by British Engineer Sir Joseph Whitworth (1803 - 87). It is used in many types of engineering particularly in aluminium. Angle of Thread = 55 Degrees Sizes range from 1/16" to 2-1/2"

 

Actions Size Outside Dia Inch Tpi Pitch Inch Core Dia Inch Radius Inch Thread Depth Thou Hex A/flats Inch Head Depth Inch Washer Face Dia Inch Standard Nut Depth Inch Lock Nut Depth Inch Tapping Drill Size Inch Tapping Drill Size Mm Letter Or Number Id
1/16 0.063 60.000 0.017 0.041 0.002 11 0.047 1.1 56 1
3/32 0.094 48.000 0.028 0.067 0.003 13 0.070 1.8 50 2
1/8 0.125 40.000 0.025 0.093 0.003 16 0.338 0.098 2.5 40 3
5/32 0.156 32.000 0.031 0.116 0.004 20 0.120 3.1 31 4
3/16 0.188 24.000 0.042 0.134 0.006 27 0.445 0.146 3.7 27 5
7/32 0.219 24.000 0.042 0.165 0.006 27 0.173 4.4 17 6
1/4 0.250 20.000 0.050 0.186 0.007 32 0.525 0.176 0.428 0.200 0.185 0.201 5.1 8 7
5/16 0.313 18.000 0.056 0.241 0.008 36 0.600 0.218 0.508 0.250 0.210 0.256 6.5 E 8
3/8 0.375 16.000 0.063 0.295 0.009 40 0.710 0.260 0.582 0.312 0.260 0.313 8.0 5/16 9
7/16 0.438 14.000 0.071 0.346 0.010 46 0.820 0.302 0.690 0.375 0.275 0.362 9.2 23/64 10
1/2 0.500 12.000 0.083 0.393 0.011 53 0.920 0.343 0.800 0.437 0.300 0.413 10.5 Z 11
9/16 0.563 12.000 0.083 0.456 0.011 53 1.010 0.375 0.900 0.500 0.333 0.476 12.1 31/64 12
5/8 0.625 11.000 0.091 0.509 0.013 58 1.100 0.417 0.985 0.562 0.375 0.532 13.5 17/32 13
11/16 0.688 11.000 0.091 0.571 0.013 58 1.200 0.594 15.0 19/32 14
3/4 0.750 10.000 0.100 0.622 0.014 64 1.300 0.500 1.175 0.687 0.458 0.641 16.3 41/64 15
13/16 0.813 10.000 0.100 0.684 0.014 64 1.390 0.713 18.1 23/32 16
7/8 0.875 9.000 0.111 0.733 0.015 711 1.480 0.583 1.273 0.750 0.500 0.750 19.3 3/4 17
15/16 0.938 9.000 0.111 0.795 0.015 71 1.575 0.828 21.0 53/64 18
1 1.000 8.000 0.125 0.840 0.017 80 1.670 0.666 1.453 0.875 0.583 0.866 22.0 55/64 19
1 - 1/8 1.125 7.000 0.143 0.942 0.020 92 1.860 0.750 1.620 1.000 0.666 0.974 24.8 31/32 20
1 - 1/4 1.250 7.000 0.143 1.067 0.020 92 2.050 0.830 1.795 1.125 0.750 1.094 27.5 1 - 3/32 21
1 - 3/8 1.375 6.000 0.167 1.162 0.023 107 2.220 0.920 1.985 1.250 0.833 1.188 30.0 1 - 3/8 22
1 - 1/2 1.500 6.000 0.167 1.287 0.023 107 2.410 1.000 2.155 1.375 0.916 1.319 33.5 1 - 5/16 23
1 - 5/8 1.625 5.000 0.200 1.369 0.028 128 2.580 1.375 35.0 1 - 3/8 24
1 - 3/4 1.750 5.000 0.200 1.494 0.028 128 2.760 1.170 2.495 1.625 1.083 1.535 39.0 1 - 17/32 25
1 - 7/8 1.875 5.000 0.222 1.590 0.031 142 1.625 41.0 1 - 5/8 26
2 2.000 5.000 0.222 1.715 0.031 142 3.150 1.330 2.675 1.750 1.166 1.752 44.5 1 - 3/4 27