Hydraulic Plumbing systems use different ways of sealing depending on the geographical region, size of the pressure system and the environment. There are regional differences in sealing types as well as industry preferences. For example, most European Espresso Machines and Coffee Makers use BSPP adapters while most plumbing installations in North America use NPT fittings.
Use the charts below to measure and identify your fittings.
BSPT & BSPP SIZE & PITCH |
DASH SIZE |
BSPT MALE THREAD OD |
BSPP MALE THREAD OD |
BSPT FEMALE THREAD ID |
BSPP FEMALE THREAD ID |
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inch – TPI | mm | inch | mm | inch | mm | inch | mm | inch | |
1/8 – 28 | -02 | 9,5 | 0.37 | 9,6 | 0.38 | 8,4 | 0.33 | 8,6 | 0.34 |
1/4 – 19 | -04 | 12,8 | 0.50 | 13,0 | 0.51 | 11,2 | 0.44 | 11,9 | 0.47 |
3/8 – 19 | -06 | 16,3 | 0.64 | 16,5 | 0.65 | 14,7 | 0.59 | 15,2 | 0.60 |
1/2 – 14 | -08 | 20,4 | 0.80 | 20,8 | 0.82 | 18,3 | 0.72 | 19,1 | 0.75 |
5/8 – 14 | -10 | 22,5 | 0.89 | 22,8 | 0.90 | 20,6 | 0.81 | 20,8 | 0.82 |
3/4 – 14 | -12 | 25,9 | 1.02 | 26,3 | 1.04 | 23,9 | 0.94 | 24,6 | 0.97 |
1 – 11 | -16 | 32,6 | 1.28 | 33,1 | 1.30 | 29,7 | 1.17 | 30,7 | 1.21 |
BSPT (British Standard Pipe Thread) is similar to NPT except there are important differences. The angle across the flanks of threads (if you sliced the fitting in half long-ways and measured the angle from root to crest to root) is 55 degrees instead of 60 degrees as it is for NPT.
NPT THREAD SIZE & PITCH |
DASH SIZE |
MALE THREAD MINOR OD |
FEMALE THREAD ID |
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inch – TPI | mm | inch | mm | inch | |
1/8 – 27 | -02 | 9,9 | 0.39 | 8,4 | 0.33 |
1/4 – 18 | -04 | 13,2 | 0.52 | 11,2 | 0.44 |
3/8 – 18 | -06 | 16,6 | 0.65 | 14,7 | 0.58 |
1/2 – 14 | -08 | 20,6 | 0.81 | 17,8 | 0.70 |
3/4 – 14 | -12 | 26,0 | 1.02 | 23,4 | 0.92 |
1 – 11.1/2 | -16 | 32,5 | 1.28 | 29,5 | 1.16 |
NPT stands for National Pipe Tapered threads, also known as ANSI/ASME B1. 20.1 pipe threads. It is a U.S. standard for measuring tapered threads on threaded pipes and fittings. Threaded pipes can give an effective seal for pipes using hydraulic fluids.
Thread Dimension of Compression Fitting
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