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Do you need more information about thread types or are you looking for a special solution? Please contact our Sales Engineers.


電話: +886-(0)3-5600560
傳真: +886-3-5600525

The most common types of pipe thread are:

  • NPT - American Taper Pipe Thread  = National Pipe Taper
  • NPTF - American Taper Pipe Thread for dryseal joint without sealant compound = National Pipe Taper Fuel

NPT GAS thread

NPT and NPTF appear to be identical. Both have the same pitch diameter at the top of the hole of the internal thread or end of the pipe on external threads and both have the same thread lengths or depths. However, there is a subtle difference in the root and crest diameters of the threads.

NPT threads are also sometimes referred to as:

  • MIP (Male Iron Pipe)
  • FIP (Female Iron Pipe)
  • IPT (Iron Pipe Thread)
  • FPT (Female Pipe Thread)
  • MPT (Male Pipe Thread)

Note that these references are somewhat casual, and might possibly be used in reference to NPS instead of NPT thread. NPS thread (National Pipe Straight) is not interchangeable with NPT thread.

If you have any questions please contact us or check out our fittings with NPT thread.


Thread size Major diameter (mm) TPI
1/16" - 27 NPT 7,938 27
1/8" - 27 NPT 10,287 27
1/4"- 18 NPT 13,716 18
3/8" - 18 NPT 17,145 18
1/2" - 14 NPT 21,336 14
3/4" - 14 NPT 26,670 14
1" - 11½ NPT 33,401 11,5
2" - 11½ NPT 60,325 11,5

Flank angle is 60 °.
Female and male thread are both tapered at equal angles.
Flank angle NPT / NPTF