#3 Steel B Nut

The #3 Steel B Nut is a precision tube fitting connector designed for high-pressure fluid and fuel line applications in automotive, aerospace, and industrial systems. Built to connect 3/16-inch diameter tubing using AN (Army-Navy) standard specifications, this nickel-plated steel nut ensures reliable, leak-free connections in demanding environments. Technicians and engineers choose B-series nuts for their superior holding power and vibration resistance compared to standard fittings.

Manufactured from hardened steel and finished with nickel plating, the #3 Steel B Nut offers corrosion resistance and extended service life in both wet and dry applications. The AN3 size class accommodates 3/16-inch tubing with a secure threaded connection that prevents accidental loosening under vibration and thermal cycling. The nickel-plated finish protects against oxidation while maintaining aesthetic appeal in visible installations, and the robust design withstands pressure spikes common in fuel injection systems, hydraulic circuits, and pneumatic lines.

This fitting is essential for restoration work on classic vehicles, race car fuel systems, and custom fabrication projects where OEM-quality connections are non-negotiable. The pair format allows technicians to complete dual-line applications without additional purchases. Installation requires a wrench that properly engages the hex body, ensuring torque is applied without deforming the nut or damaging the tubing seat, making it compatible with standard -3 AN hose and tube assemblies across domestic and import platforms.