Thread data
NPTF thread chart and dimensions
American Dryseal tapered pipe thread. It has the NPT taper and pitch, but the crests and roots are controlled so they crush together and seal without tape or sealant. Specified on fuel, hydraulic and air ports where sealant could contaminate the system.
- Standard
- SAE J476, ASME B1.20.3 Dryseal
- Seals by
- Dryseal taper, thread crests and roots crush to seal without sealant
- Used for
- Fuel, hydraulic and air ports where sealant is not allowed
- Sizes
- 1/16 to 3
NPTF dimensions
The dimensions we machine to. Pressure values are nominal working ratings for steel at room temperature.
| Size | Male | Female | Threads per inch | Pipe OD | Pitch dia E0 | Pitch dia E1 | Hand tight L1 | Effective L2 | Taper | Tap drill | Thread class | Rated to |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/16 | 1/16-27 NPTF | 1/16-27 NPTF | 27 | 7.94 mm | 6.89 mm | 7.14 mm | 4.06 mm | 6.63 mm | 1:16 on diameter | C (6.15 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 10,000 psi |
| 1/8 | 1/8-27 NPTF | 1/8-27 NPTF | 27 | 10.29 mm | 9.23 mm | 9.52 mm | 4.57 mm | 6.70 mm | 1:16 on diameter | R (8.61 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 10,000 psi |
| 1/4 | 1/4-18 NPTF | 1/4-18 NPTF | 18 | 13.72 mm | 12.13 mm | 12.44 mm | 5.08 mm | 10.21 mm | 1:16 on diameter | 7/16 (11.11 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 8,000 psi |
| 3/8 | 3/8-18 NPTF | 3/8-18 NPTF | 18 | 17.14 mm | 15.55 mm | 15.93 mm | 6.10 mm | 10.36 mm | 1:16 on diameter | 37/64 (14.68 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 6,000 psi |
| 1/2 | 1/2-14 NPTF | 1/2-14 NPTF | 14 | 21.34 mm | 19.26 mm | 19.77 mm | 8.13 mm | 13.56 mm | 1:16 on diameter | 23/32 (18.26 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 6,000 psi |
| 3/4 | 3/4-14 NPTF | 3/4-14 NPTF | 14 | 26.67 mm | 24.58 mm | 25.12 mm | 8.61 mm | 13.86 mm | 1:16 on diameter | 59/64 (23.42 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 5,000 psi |
| 1 | 1-11.5 NPTF | 1-11.5 NPTF | 11.5 | 33.40 mm | 30.83 mm | 31.46 mm | 10.16 mm | 17.34 mm | 1:16 on diameter | 1 5/32 (29.36 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 5,000 psi |
| 1 1/4 | 1 1/4-11.5 NPTF | 1 1/4-11.5 NPTF | 11.5 | 42.16 mm | 39.55 mm | 40.22 mm | 10.67 mm | 17.95 mm | 1:16 on diameter | 1 1/2 (38.10 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 3,000 psi |
| 1 1/2 | 1 1/2-11.5 NPTF | 1 1/2-11.5 NPTF | 11.5 | 48.26 mm | 45.62 mm | 46.29 mm | 10.67 mm | 18.38 mm | 1:16 on diameter | 1 47/64 (44.04 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 3,000 psi |
| 2 | 2-11.5 NPTF | 2-11.5 NPTF | 11.5 | 60.32 mm | 57.63 mm | 58.33 mm | 11.07 mm | 19.22 mm | 1:16 on diameter | 2 7/32 (56.36 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 2,500 psi |
| 2 1/2 | 2 1/2-8 NPTF | 2 1/2-8 NPTF | 8 | 73.02 mm | 69.08 mm | 70.54 mm | 23.50 mm | 28.89 mm | 1:16 on diameter | 2 5/8 (66.67 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 2,000 psi |
| 3 | 3-8 NPTF | 3-8 NPTF | 8 | 88.90 mm | 84.85 mm | 86.36 mm | 24.13 mm | 30.48 mm | 1:16 on diameter | 3 1/4 (82.55 mm) | Dryseal: truncation controlled so crests and roots seal without sealant | 1,500 psi |
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