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 6.837 6.561 28 0.907
G 1/8" 0.125 9.728 8.841 8.565 28 0.907
G 1/4" 0.250 13.157 11.863 11.445 19 1.337
G 3/8" 0.375 16.662 15.389 14.950 19 1.337
G 1/2" 0.500 20.955 19.200 18.633 14 1.814
G 3/4" 0.750 26.441 24.772 24.120 14 1.814
G 1" 1.000 33.249 31.014 30.292 11 2.309
G 1 1/4" 1.250 41.910 39.819 38.953 11 2.309
G 1 1/2" 1.500 47.803 45.712 44.846 11 2.309
G 2" 2.000 59.614 57.722 56.657 11 2.309
G 2 1/2" 2.500 75.184 73.391 72.227 11 2.309
G 3" 3.000 87.884 86.289 84.927 11 2.309
G 4" 4.000 113.030 111.733 110.073 11 2.309
G 5" 5.000 138.430 137.332 135.473 11 2.309
G 6" 6.000 163.830 162.732 160.873 11 2.309