Whitworth Parallel Pipe Thread
DIN ISO 228 (DIN 259)
BSPP (British Standard Pipe Parallel)

British Standard Pipe Parallel Thread, with sealant compound,(parallel, cylindrical), external = G.
The flank angle is 55°.

Nominal
Diameter
Major
Diameter
Inch
Major
Diameter
mm
Minor Diamter
Nut
mm
Tapping
Drill Size
mm
TPI Pitch
mm
G 1/16" 0.063 7.722 6.843 6.561 28 0.907
G 1/8" 0.125 9.728 8.848 8.565 28 0.907
G 1/4" 0.250 13.157 11.890 11.445 19 1.337
G 3/8" 0.375 16.662 15.395 14.950 19 1.337
G 1/2" 0.500 20.955 19.172 18.633 14 1.814
G 5/8" 0.625 22.911 21.128 20.587 14 1.814
G 3/4" 0.750 26.441 24.658 24.120 14 1.814
G 7/8" 0.875 30.201 28.418 27.877 14 1.814
G 1" 1.000 33.249 30.931 30.292 11 2.309
G 1 1/8" 1.125 37.897 35.579 34.939 11 2.309
G 1 1/4" 1.250 41.910 39.592 38.953 11 2.309
G 1 3/8" 1.375 44.323 42.005 41.365 11 2.309
G 1 1/2" 1.500 47.803 45.485 44.846 11 2.309
G 1 5/8" 1.625 52.883 50.566 49.926 11 2.309
G 1 3/4" 1.750 53.746 51.428 50.788 11 2.309
G 1 7/8" 1.875 56.998 54.681 54.041 11 2.309
G 2" 2.000 59.614 57.296 56.657 11 2.309
G 2 1/4" 2.250 65.710 62.752 63.392 11 2.309
G 2 1/2" 2.500 75.184 73.391 72.227 11 2.309
G 2 3/4" 2.750 81.534 78.576 79.216 11 2.309
G 3" 3.000 87.884 86.289 84.927 11 2.309
G 3 1/2" 3.500 100.330 97.372 98.012 11 2.309
G 4" 4.000 113.030 111.733 110.073 11 2.309
G 4 1/2" 4.500 125.730 122.772 123.412 11 2.309
G 5" 5.000 138.430 137.332 135.473 11 2.309
G 5 1/2" 5.500 151.130 148.172 148.812 11 2.309
G 6" 6.000 163.830 162.732 160.873 11 2.309