Merit Brass X119-04 Brass Pipe Locknut 1/4 in Fnpt

Product Description

The MERIT BRASS X119-04 is a 1/4 inch brass pipe locknut designed to secure fittings and fixtures in threaded pipe assemblies. It connects using female NPT (FNPT) threads on both ends and is rated at 125 psi, placing it in the Class 125 pressure category. The locknut is machined from brass, which provides corrosion resistance in a wide range of fluid-handling applications. Licensed plumbers and pipefitters install this hardware as a mechanical fastener to lock a fitting body against a panel, tank wall, or manifold surface, preventing rotation and maintaining a leak-free seal under sustained system pressure.

This locknut is suited for use in residential and light commercial plumbing systems where 1/4 inch FNPT threaded connections are required. Typical applications include panel-mount fittings, gauge connections, valve assemblies, and low-pressure fluid distribution lines. Its compact size and standard thread make it a common stock item in service vans and shop inventory for quick-turn repair and installation work.

Key Features

• 1/4 inch FNPT threaded connection for standard pipe assemblies
• Class 125 pressure rating at 125 psi for low-to-moderate pressure systems
• Brass construction provides natural corrosion resistance without additional coating
• Locknut design prevents fitting rotation when mounted through panels or tank walls
• Lightweight at 0.03 pounds for easy handling and high-volume installation

Compatibility

Designed as an OEM-style replacement or new-installation locknut for 1/4 inch FNPT threaded pipe fittings in Class 125 plumbing and fluid-handling systems.

Installation Notes

Installation is performed by licensed plumbers or qualified pipefitters. Shut off system pressure and drain the line before removing or installing any threaded fittings. Hand-tighten first, then use an appropriate wrench to achieve a snug, leak-free fit — do not overtighten brass fittings, as the material is softer than steel and can crack under excessive torque. Verify that thread standards match before assembly and test the connection under working pressure before returning the system to service.