Merit Brass K419-64 Pipe Locknut 4 in 304 Ss Threaded

Product Description

The MERIT BRASS K419-64 is a 4-inch pipe locknut designed for threaded pipe assemblies in commercial and industrial plumbing applications. Manufactured from 304 stainless steel, it delivers corrosion resistance in wet, chemical-exposed, or outdoor environments. The female NPT straight locknut (FNPSL) end connection meets ISO standards and carries a 150 psi pressure rating. At 5-5/32 inches in length and weighing 1.71 pounds, this locknut is built to secure pipe fittings firmly against panels, bulkheads, and enclosures. Licensed plumbers and pipefitters are the typical installers for this component.

This locknut is suited for 4-inch threaded pipe installations in commercial plumbing, industrial process piping, and mechanical systems where stainless steel construction is required for corrosion resistance or sanitary compliance. The FNPSL threading makes it compatible with standard NPT straight-thread pipe ends. It is appropriate for both new construction and retrofit work in systems operating at or below 150 psi.

Key Features

• 304 stainless steel construction for corrosion resistance in demanding environments
• FNPSL (female NPT straight locknut) end connection for standard threaded pipe compatibility
• 150 psi pressure rating suitable for a wide range of commercial and industrial systems
• Meets ISO standards for dimensional and performance compliance
• 5-5/32 inch length accommodates bulkhead and panel mounting applications

Compatibility

Designed as an OEM-style replacement or new-installation locknut for 4-inch threaded pipe systems using NPT straight-thread connections in commercial and industrial plumbing.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter following applicable IPC or local plumbing code requirements. Shut off and depressurize the pipe system completely before removing or installing any threaded fittings. Use appropriate pipe wrenches sized for 4-inch fittings and apply thread sealant or tape as required by the system and code. Do not exceed the 150 psi rated working pressure of this fitting.