1/4" NPT Thread Size
Complete thread specifications for 1/4 inch NPT threads. Widely used for instrumentation, pressure gauges, and pneumatic fittings.
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NPT threads follow ASME B1.20.1 standard with 1:16 taper
Note: This page shows 1/4" NPT dimensions. Use the dropdown above to explore other sizes.
Thread Specifications
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1/4" NPT Thread Specifications
The 1/4 inch NPT thread is a standard size for instrumentation and control applications. With 18 TPI and compact 0.5400" major diameter, it's perfect for pressure gauges, temperature sensors, and pneumatic quick-connects.
Key Dimensions
- Major Diameter: 0.5400" (13.72 mm)
- Minor Diameter: 0.4795" (12.18 mm)
- Threads Per Inch: 18 TPI
- Drill Tap Size: 7/16" (11.11 mm)
Common Applications
- Pressure gauges and transducers
- Pneumatic air tools and fittings
- Temperature sensors and thermowells
- Instrument panel connections
- Compressed air quick-disconnects