NPT pipe thread measurements can get confusing, here's a handy chart to help you fit all your parts together seamlessly.

OD Actual (Inches) Pipe Thread Size Threads Per Inch
5/16" 1/16" 27
32/79" 1/8" 27
27/50" 1/4" 18
27/40" 3/8" 18
21/25" 1/2" 14
1 1/20" 3/4" 14
1 23/73" 1" 11-1/2
1 33/50" 1 1/4" 11-1/2
1 9/10" 1 1/2" 11-1/2
2 3/8" 2" 11-1/2
2 7/8" 2 1/2" 8
3 1/2" 3" 8
4" 3 1/2" 8
4 1/2" 4" 8
5 49/87" 5" 8
6 5/8" 6" 8
8 5/8" 8" 8
10 3/4" 10" 8
12 3/4" 12" 8
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