ASME B1.20.1 Pipe Thread Tolerances
Pipe Thread Standards for Taper Thread Fittings Manufactured Per ASME B1.20.1 (1983) ASME STANDARD, B1.20.1* TAPER PIPE THREAD DIMENSIONS** | ||||
|---|---|---|---|---|
| NOMINAL PIPE SIZE | NUMBER OF THREADS PER INCH | OUTSIDE DIAMETER OF PIPE "D" | PITCH DIAMETER AT BEGINNING OF EXTERNAL THREAD "E" | LENGTH OF EFFECTIVE THREAD, EXTERNAL "F" |
| 1/8" | 27 | .405 | .36351 | .2639 |
| 1/4" | 18 | .540 | .47739 | .4018 |
| 3/8" | 18 | .675 | .61201 | .4078 |
| 1/2" | 14 | .840 | .75843 | .5337 |
| 3/4" | 14 | 1.050 | .96768 | .5457 |
| 1" | 11.5 | 1.315 | 1.21363 | .6828 |
| 1-1/4" | 11.5 | 1.660 | 1.55713 | .7068 |
| 1-1/2" | 11.5 | 1.900 | 1.79609 | .7235 |
| 2" | 11.5 | 2.375 | 2.26902 | .7565 |
| 2-1/2" | 8 | 2.875 | 2.71953 | 1.1375 |
| 3" | 8 | 3.500 | 3.34062 | 1.2000 |
| 3-1/2" | 8 | 4.000 | 3.83750 | 1.2500 |
| 4" | 8 | 4.500 | 4.33438 | 1.3000 |
| * For more information on the complete ASME specification consult your penn machine representative. ** ALL DIMENSIONS ARE IN INCHES. ** The dimensions given here do not allow for variations in tapping or threading. Standard gaging tolerance equals plus or minus one thread on both male and female threads. | ||||