1 inch NPT Thread Dimensions — ASME B1.20.1
1 inch (DN 25) to ASME B1.20.1: Threads — per inch 11.5 mm; Pitch 2.209 mm; Pipe OD 33.40 mm; Hand-tight 10.16 mm; Effective thread 17.34 mm.
Key to dimensions
1 inch NPT Thread Dimensions — ASME B1.20.1 — all dimensions
NPT basic thread dimensions
| Dimension | Value | Equivalent |
|---|---|---|
| Threads — per inch | 11.5 mm | 0.453 in |
| Pitch | 2.209 mm | 0.087 in |
| Pipe OD | 33.40 mm | 1.31 in |
| Hand-tight — L1 | 10.16 mm | 0.400 in |
| Effective thread — L2 | 17.34 mm | 0.683 in |
| Pitch dia at end — E0 | 30.826 mm | 1.21 in |
| Pitch dia at hand-tight — E1 | 31.461 mm | 1.24 in |
| Tap drill — mm, approx. | 29.37 mm | 1.16 in |
Values are nominal, from NPT Thread Dimensions — ASME B1.20.1. Verify critical dimensions against the current edition of the standard before design, purchase or fabrication.
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Other sizes — NPT Thread Dimensions — ASME B1.20.1
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1 inch NPT Thread Dimensions — ASME B1.20.1: common questions
What are the 1 inch NPT Thread Dimensions — ASME B1.20.1?
1 inch (DN 25) to ASME B1.20.1: Threads — per inch 11.5 mm; Pitch 2.209 mm; Pipe OD 33.40 mm; Hand-tight 10.16 mm; Effective thread 17.34 mm.
Does Teshi Group manufacture 1 inch forged fittings?
Yes. Teshi Group is an OEM manufacturer in India of forged fittings to ASME B1.20.1, in carbon, alloy, stainless, duplex, super duplex, nickel alloys, titanium and Cu-Ni, with EN 10204 3.1 certificates.
Can I download the 1 inch dimensions as a PDF?
Yes. Use “Download PDF for this size” on this page to get a single-size, print-ready PDF with the drawing and every tabulated dimension, or download the full NPT Thread Dimensions — ASME B1.20.1 chart.
Need 1 inch forged fittings?
Teshi Group manufactures them in India — send your size, rating and material and get a quote in 24–48 hours.
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