National Pipe Thread (NPT)
National Pipe Thread Profile
- Thread form angle : 60°
- The taper rate of national pipe thread : 1 in 16
- P : Pitch
- n : TPI
- H : Height of fundamental triangle
- h : Height of thread
- f : depth of truncation at crest or root
- D : Major diameter of internal thread
- D1 : Minor diameter of internal thread
- D2 : Pitch diameter of internal thread
- d : Major diameter of external thread
- d1 : Minor diameter of external thread
- d2 : Pitch diameter of external thread
- L1 : Handtight engagement length
- L2 : Effective thread length (external)
- L3 : Wrench makeup length for internal thread
National Pipe Thread Dimension
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Number of threads per inch (TPI) :
n =
0.000
mm
Pitch :
P =
0.000
mm
Height of fundamental triangle :
H =
0.000
mm
Height of thread :
h =
0.000
mm
Crest and root truncation :
Minimum f =
0.000
mm
Maximum f =
0.000
mm
Handtight engagement length :
L1 =
0.000
mm
Effective thread length (external) :
L2 =
0.000
mm
Wrench makeup length for internal thread :
L3 =
0.000
mm
Major diameter (mm)
0.000
0.000
0.000
=
invalid size
Minor diameter (mm)
0.000
0.000
0.000
=
invalid size
Pitch diameter (mm)
0.000
not specified
not specified
=
invalid size
For not specified tolerance, it means zero.
Standard National Pipe Thread
| Size | TPI |
|---|---|
| 1/16 | 27 |
| 1/8 | 27 |
| 1/4 | 18 |
| 3/8 | 18 |
| 1/2 | 14 |
| 3/4 | 14 |
| 1 | 11.5 |
| 1 1/4 | 11.5 |
| 1 1/2 | 11.5 |
| 2 | 11.5 |
| 2 1/2 | 8 |
| 3 | 8 |
| 3 1/2 | 8 |
| 4 | 8 |
| 5 | 8 |
| 6 | 8 |
| 8 | 8 |
| 10 | 8 |
| 12 | 8 |
| 14 O.D. | 8 |
| 16 O.D. | 8 |
| 18 O.D. | 8 |
| 20 O.D. | 8 |
| 24 O.D. | 8 |
Related topic
How to create a taper thread profile with CAD software