Whitworth's Standard Threads for Pipes (in)

Written by Matt Milbury. Posted in Thread Datasheets

Nominal

Bore of

Pipe

Diameter

of Pipe

Diameter

at Bottom

of Thread

Number

of Threads

per Inch

1/8 0.382 0.336 28
1/4 0.518 0.451 19
3/8 0.656 0.589 19
1/2 0.826 0.734 14
5/8 0.902 0.811 14
3/4 1.04 0.949 14
7/8 1.189 1.097 14
1 1.309 1.192 11
1 1/8 1.492 1.375 11
1 1/4 1.65 1.533 11
1 3/8 1.745 1.628 11
1 1/2 1.882 1.765 11
1 5/8 2.022 1.965 11
1 3/4 2.16 2.042 11
1 7/8 2.245 2.128 11
2 2.347 2.23 11
2 1/8 2.467 2.351 11
2 1/4 2.587 2.47 11
2 3/8 2.794 2.678 11
2 1/2 3 2.882 11
2 5/8 3.124 3.009 11
2 3/4 3.247 3.13 11
2 7/8 3.367 3.251 11
3 3.485 3.368 11
3 1/4 3.698 3.581 11
3 1/2 3.912 3.795 11
3 3/4 4.125 4.008 11
4 4.340 4.223 11