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BSPF Threads ( British Standard Pipe Parrallel Fine )

G 1/16" - G 1" G 1 1/8" - G 3" G 3 1/4" - -G 6"

Size Thread Designation Major Dia External Thread Internal Thread Tap Drill
Size pitch Class Major Dia Pitch Dia Minor Dia Class Minor Dia Pitch Dia Major Dia
mm mm TPI Max Min Max Min Max Min Min Max Min Max Min Max mm
G 1/16" BSPF 7.723 0.907 28 A 7.723 7.509 7.142 7.035 6.561 - - 6.561 6.834 7.142 7.249 7.723 - 6.8
G 1/16" BSPF 7.723 0.907 28 B 7.723 7.509 7.142 6.928 6.561 - - - - - - - - -
G 1/8" BSPF 9.728 0.907 28 A 9.728 9.514 9.147 9.04 8.566 - - 8.566 8.848 9.147 9.254 9.728 - 8.8
G 1/8" BSPF 9.728 0.907 28 B 9.728 9.514 9.147 8.933 8.566 - - - - - - - - -
G 1/4" BSPF 13.157 1.337 19 A 13.157 12.907 12.301 12.176 11.445 - - 11.445 11.89 12.301 12.426 13.157 - 11.8
G 1/4" BSPF 13.157 1.337 19 B 13.157 12.907 12.301 12.051 11.445 - - - - - - - - -
G 3/8" BSPF 16.662 1.337 19 A 16.662 16.412 15.806 15.681 14.95 - - 14.95 15.395 15.806 15.931 16.662 - 15.25
G 3/8" BSPF 16.662 1.337 19 B 16.662 16.412 15.806 15.556 14.95 - - - - - - - - -
G 1/2" BSPF 20.955 1.814 14 A 20.955 20.671 19.793 19.651 18.631 - - 18.631 19.172 19.793 19.935 20.955 - 19
G 1/2" BSPF 20.955 1.814 14 B 20.955 20.671 19.793 19.509 18.631 - - - - - - - - -
G 5/8" BSPF 22.911 1.814 14 A 22.911 22.627 21.749 21.607 20.587 - - 20.587 21.128 21.749 21.891 22.911 - 21
G 5/8" BSPF 22.911 1.814 14 B 22.911 22.627 21.749 21.465 20.587 - - - - - - - - -
G 3/4" BSPF 26.441 1.814 14 A 26.441 26.157 25.279 25.137 24.117 - - 24.117 24.658 25.279 25.421 26.441 - 24.5
G 3/4" BSPF 26.441 1.814 14 B 26.441 26.157 25.279 24.995 24.117 - - - - - - - - -
G 7/8" BSPF 30.201 1.814 14 A 30.201 29.917 29.039 28.897 27.877 - - 27.877 28.418 29.039 29.181 30.201 - 28.25
G 7/8" BSPF 30.201 1.814 14 B 30.201 29.917 29.039 28.755 27.877 - - - - - - - - -
G 1" BSPF 33.249 2.309 11 A 33.249 32.889 31.77 31.59 30.291 - - 30.291 30.931 31.77 31.95 33.249 - 30.75
G 1" BSPF 33.249 2.309 11 B 33.249 32.889 31.77 31.41 30.291 - - - - - - - - -
G 1 1/8" BSPF 37.897 2.309 11 A 37.897 37.537 36.418 36.238 34.939 - - 34.939 35.579 36.418 36.598 37.897 - 35.5
G 1 1/8" BSPF 37.897 2.309 11 B 37.897 37.537 36.418 36.058 34.939 - - - - - - - - -
G 1 1/4" BSPF 41.91 2.309 11 A 41.91 41.55 40.431 40.251 38.952 - - 38.952 39.592 40.431 40.611 41.91 - 39.5
G 1 1/4" BSPF 41.91 2.309 11 B 41.91 41.55 40.431 40.071 38.952 - - - - - - - - -
G 1 3/8" BSPF 44.323 2.309 11 - 44.323 - - - - - - - 41.365 42.005 - - - 41.75
G 1 1/2" BSPF 47.803 2.309 11 A 47.803 47.443 46.324 46.144 44.845 - - 44.845 45.485 46.324 46.504 47.803 - 45.25
G 1 1/2" BSPF 47.803 2.309 11 B 47.803 47.443 46.324 45.964 44.845 - - - - - - - - -
G 1 5/8" BSPF 52 2.309 11 - 52 - - - - - - - 49.03 49.67 - - - 49.5
G 1 3/4" BSPF 53.746 2.309 11 A 53.746 53.386 52.267 52.087 50.788 - - 50.788 51.428 52.267 52.447 53.746 - 51
G 1 3/4" BSPF 53.746 2.309 11 B 53.746 53.386 52.267 51.907 50.788 - - - - - - - - -
G 2" BSPF 59.614 2.309 11 A 59.614 59.254 58.135 57.955 56.656 - - 56.656 57.296 58.135 58.315 59.614 - 57
G 2" BSPF 59.614 2.309 11 B 59.614 59.254 58.135 57.775 56.656 - - - - - - - - -
G 2 1/4" BSPF 65.71 2.309 11 A 65.71 65.276 64.231 64.014 62.752 - - 62.752 63.392 64.231 64.448 65.71 - 63.3
G 2 1/4" BSPF 65.71 2.309 11 B 65.71 65.276 64.231 63.797 62.752 - - - - - - - - -
G 2 1/2" BSPF 75.184 2.309 11 A 75.184 74.75 73.705 73.488 72.226 - - 72.226 72.866 73.705 73.922 75.184 - 72.8
G 2 1/2" BSPF 75.184 2.309 11 B 75.184 74.75 73.705 73.271 72.226 - - - - - - - - -
G 2 3/4" BSPF 81.534 2.309 11 A 81.534 81.1 80.055 79.838 78.576 - - 78.576 79.216 80.055 80.272 81.534 - 79.1
G 2 3/4" BSPF 81.534 2.309 11 B 81.534 81.1 80.055 79.621 78.576 - - - - - - - - -
G 3" BSPF 87.884 2.309 11 A 87.884 87.45 86.405 86.188 84.926 - - 84.926 85.566 86.405 86.622 87.884 - 85.5
G 3" BSPF 87.884 2.309 11 B 87.884 87.45 86.405 85.971 84.926 - - - - - - - - -
G 3 1/4" BSPF 93.98 2.309 11 - 93.984 - - - - - - - 91.022 91.66 - - - 91
G 3 1/2" BSPF 100.33 2.309 11 A 100.33 99.896 98.851 98.634 97.372 - - 97.372 98.012 98.851 99.068 100.33 - 97.75
G 3 1/2" BSPF 100.33 2.309 11 B 100.33 99.896 98.851 98.417 97.372 - - - - - - - - -
G 3 3/4" BSPF 106.68 2.309 11 - 106.68 - - - - - - - 103.722 104.3 - - - 104
G 4" BSPF 113.03 2.309 11 A 113.03 112.596 111.551 111.334 110.072 - - 110.072 110.712 111.551 111.768 113.03 - 110.5
G 4" BSPF 113.03 2.309 11 B 113.03 112.596 111.551 111.117 110.072 - - - - - - - - -
G 4 1/2" BSPF 125.73 2.309 11 A 125.73 125.296 124.251 124.034 122.772 - - 122.772 123.412 124.251 124.468 125.73 - 123
G 4 1/2" BSPF 125.73 2.309 11 B 125.73 125.296 124.251 123.817 122.772 - - - - - - - - -
G 5" BSPF 138.43 2.309 11 A 138.43 137.996 136.951 136.734 135.472 - - 135.472 136.112 136.951 137.168 138.43 - 136
G 5" BSPF 138.43 2.309 11 B 138.43 137.996 136.951 136.517 135.472 - - - - - - - - -
G 5 1/2" BSPF 151.13 2.309 11 A 151.13 150.696 149.651 149.434 148.172 - - 148.172 148.812 149.651 149.868 151.13 - 148.5
G 5 1/2" BSPF 151.13 2.309 11 B 151.13 150.696 149.651 149.217 148.172 - - - - - - - - -
G 6" BSPF 163.83 2.309 11 A 163.83 163.396 162.351 162.134 160.872 - - 160.872 161.512 162.351 162.568 163.83 - 161.5
G 6" BSPF 163.83 2.309 11 B 163.83 163.396 162.351 161.917 160.872 - - - - - - - - -