3/4 NPT Thread Specs
Standard: ASME B1.20.1 (NPT)
Technical parameters and design data for the 3/4 NPT pipe thread.
Established under standard ASME B1.20.1, this thread uses a pitch of 0.07143 inches and has 14 threads per inch.
Often used in fluid, hydraulic, or pneumatic systems, NPT/BSP threads require suitable thread sealants to assure leak-tight performance.
Dimensional Specifications
Size Designation
3/4 NPT
Nominal Diameter
1.05 in(26.67 mm)
Major Diameter
1.3046 in(33.14 mm)
TPI (Threads per Inch)
14
Pitch
0.07143 in
Pitch Diameter
1.2582 in(31.96 mm)
Minor Diameter
1.2273 in(31.17 mm)
Tap Drill size
59/64 in
Quick Unit Converter
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Frequently Asked Questions
What is the tap drill size for 3/4 NPT pipe thread?
The recommended tap drill size for a 3/4 NPT pipe thread is 59/64 inches.
What is the major diameter of a 3/4 NPT pipe thread?
For a standard 3/4 NPT pipe thread, the major diameter at the pipe reference plane is 1.3046 inches (approx. 33.14 mm).