ASME STANDARD TAPER PIPE THREAD DIMENSIONS
Nominal
Pipe Size |
Outside
Diameter of Pipe D |
Number of
Threads Per Inch |
Pitch
Diameter at Beginning of External Thread E0 |
Length2of
Effective Thread, External L2 |
Varnish
Threads V |
Handtight Engagement
|
Wrench Make-up Length for
Internal Thread |
Total Nominal
Engagement5 L1 +L3 |
||
Diam.3
E1 |
Length4
L1 |
Diam
E3 |
Length
L3 |
|||||||
1/8
|
.405
|
27
|
.36351
|
.2639
|
.1285
|
.37360
|
.1615
|
.35656
|
.1111
|
.2726
|
1/4
|
.540
|
18
|
.47739
|
.4018
|
.1928
|
.49163
|
.2278
|
.46697
|
.1667
|
.3945
|
3/8
|
.675
|
18
|
.61201
|
.4078
|
.1928
|
.62701
|
.240
|
.60160
|
.1667
|
.4067
|
1/2
|
.840
|
14
|
.75843
|
.5337
|
.2478
|
.77843
|
.320
|
.74504
|
.2143
|
.5343
|
3/4
|
1.050
|
14
|
.96768
|
.5457
|
.2478
|
.98887
|
.339
|
.95429
|
.2143
|
.5533
|
1
|
1.315
|
11-1/2
|
1.21363
|
.6828
|
.3017
|
1.23863
|
.400
|
1.19733
|
.2609
|
.6609
|
1-1/4
|
1.660
|
11-1/2
|
1.55713
|
.7068
|
.3017
|
1.58338
|
.420
|
1.54083
|
.2609
|
.6809
|
1-1/2
|
1.900
|
11-1/2
|
1.79609
|
.7235
|
.3017
|
1.82234
|
.420
|
1.77978
|
.2609
|
.6809
|
2
|
2.375
|
11-1/2
|
2.26902
|
.7565
|
.3017
|
2.29627
|
.436
|
2.25272
|
.2609
|
.6969
|
2-1/2
|
2.875
|
8
|
2.71953
|
1.1375
|
.4337
|
2.76216
|
.682
|
2.70391
|
.2500
|
.9320
|
3
|
3.500
|
8
|
3.34052
|
1.2500
|
.4337
|
3.38850
|
.766
|
3.32500
|
.2500
|
1.016
|
3-1/2
|
4.000
|
8
|
3.83750
|
1.2500
|
.4337
|
3.88881
|
.821
|
3.82188
|
.2500
|
1.071
|
4
|
4.500
|
8
|
4.33438
|
1.3000
|
.4337
|
4.38712
|
.844
|
4.31875
|
.2500
|
1.094
|
5
|
5.563
|
8
|
5.39073
|
1.4063
|
.4337
|
5.44929
|
.937
|
5.37511
|
.2500
|
1.187
|
6
|
6.625
|
8
|
6.44609
|
1.5125
|
.4337
|
6.50597
|
.958
|
6.43047
|
.2500
|
1.208
|
8
|
8.625
|
8
|
8.43359
|
1.7125
|
.4337
|
8.50003
|
1.063
|
8.41797
|
.2500
|
1.313
|
Dimensions are in inches (metric not provided).
1 The basic dimensions of the ASME Taper Pipe Thread are given in inches to four or five decimal places. While this implies a greater degree of precision than is implies a greater degree of precision than is ordinarily attained, these dimensions are the basis of gauge dimensions and are so expressed for the purpose of eliminating errors in computations
2 Also length of plug gauge.
3 Also pitch diameter at gauging notch (handtight plane).
4 Also length of thin ring gauge and length from gauging notch to small end of plug gauge.
5 Dimensions given do not allow for variations in tapping or threading. Standard gauging tolerance equals plus or minus one thread on both male and female threads.
The above information taken from the American National Standards Institute, Inc. for pipe threads, ASME B1.20.1. Metric version not available.