Common pipe thread types:
1.NPT or NPS (national pipe tapered or straight): Most common in North America
2.MIP or FIP (male or female iron pipe): Same thread dimensions as NPT
3.BSP(T) or BSP(S) (British standard pipe tapered or straight): Most common in Europe
4.Compression: A unique threaded fitting that does not mate with other thread types
5.UNS (National Unified Special): Some compatible with compression fittings
NPT Thread Chart
| NPT Nominal Size | Actual OD | Hand Tight Turns | Wrench Turns |
| 1/8 | 0.405″ | 4.5 | 2.5 |
| 1/4 | 0.54″ | 4 | 3 |
| 3/8 | 0.675″ | 4.5 | 3 |
| 1/2 | 0.84″ | 4.5 | 3 |
| 3/4 | 1.05″ | 4.5 | 3 |
| 1 | 1.32″ | 4.5 | 3.25 |
| 1 1/4 | 1.66″ | 4.5 | 3.25 |
BSP Thread Chart
| BSP Nominal Size | Major Diameter (OD) | Minor Diameter (ID) |
| 1/8 | 0.38″ | 0.34 |
| 1/4 | 0.52″ | 0.45 |
| 3/8 | 0.65″ | 0.59 |
| 1/2 | 0.83″ | 0.73 |
| 3/4 | 1.04″ | 0.95 |
| 1 | 1.30″ | 1.19 |
| 1 1/4 | 1.65″ | 1.53 |
What are the parts of a pipe thread?
1.The thread dimension refers to the major diameter or outside measurement.
2.The pitch is the distance from the peak of one crest to the opposite of another.
3.The thread angle is the difference between the threads or the valley between the peaks.