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.

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