G 1/4 Thread Specs
Standard: ISO 228 / ISO 7 (BSP)
Technical parameters and design data for the G 1/4 pipe thread.
Established under standard ISO 228 / ISO 7, this thread uses a pitch of 0.05263 inches and has 19 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
G 1/4
Nominal Diameter
0.518 in(13.16 mm)
Major Diameter
0.518 in(13.16 mm)
TPI (Threads per Inch)
19
Pitch
0.05263 in
Pitch Diameter
0.4843 in(12.3 mm)
Minor Diameter
0.4506 in(11.45 mm)
Tap Drill size
11.8 mm
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Frequently Asked Questions
What is the tap drill size for G 1/4 pipe thread?
The recommended tap drill size for a G 1/4 pipe thread is 11.8 mm.
What is the major diameter of a G 1/4 pipe thread?
For a standard G 1/4 pipe thread, the major diameter at the pipe reference plane is 0.518 inches (approx. 13.16 mm).