What is the NPT pipe thread according to ANSI B 1.20.1-1983?

The NPT pipe thread is a self-sealing thread with a flank angle of 60°, used for pressure-tight connections in pipeline systems.

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Data Table for NPT Pipe Threads ANSI B 1.20.1-1983

Here you will find the dimensions of the self-sealing NPT pipe thread according to ANSI B 1.20.1-1983 with a flank angle of 60°.

Thread	Pitch	Diameter outside [mm]	Core hole diameter at the thin end of the pipe [mm]	Number of threads per 25.4 mm
1/16“ – 27 NPT	0.941	7.895	6.00	27
1/8“ – 27 NPT	0.941	10.242	8.25	27
1/4“ – 18 NPT	1.411	13.616	10.70	18
3/8“ – 18 NPT	1.411	17.055	14.10	18
1/2“ – 14 NPT	1.814	21.223	17.40	14
3/4“ – 14 NPT	1.814	26.568	22.60	14
1“ – 11 1/2 NPT	2.209	33.228	28.50	11.5
1 1/4“ – 11 1/2 NPT	2.209	41.985	37.00	11.5
1 1/2“ – 11 1/2 NPT	2.209	48.054	43.50	11.5
2“ – 11 1/2 NPT	2.209	60.092	55.00	11.5
2 1/2“ – 8 NPT	3.175	72.699	65.50	8
3“ – 8 NPT	3.175	88.608	81.50	8
3 1/2“ – 8 NPT	3.175	101.316	94.30	8
4“ – 8 NPT	3.175	113.973	107.00	8
5“ – 8 NPT	3.175	141.300	134.384	8
6“ – 8 NPT	3.175	168.275	161.191	8
8“ – 8 NPT	3.175	219.075	211.673	8
10“ – 8 NPT	3.175	273.050	265.311	8
12“ – 8 NPT	3.175	323.850	315.793	8

Thread table: NPT pipe thread ANSI B 1.20.1-1983 (105.64 KB)

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