N-A5818CM - Miller AccuLock S Copper Nozzle, 5/8" Orifice, 1/8" Recess

Industrial-Grade Performance with AccuLock S Technology

The Miller N-A5818CM is a specialized copper nozzle designed for the MDX-250 series MIG guns, integrating the advanced AccuLock S consumable system. This system is engineered to solve common wire feeding issues by centering and locking the liner into position at the front of the gun. The nozzle itself plays a critical role in this assembly, providing the necessary shielding gas coverage and thermal protection for the front-end consumables.

Technical Specifications & Design
This nozzle features a 5/8-inch (15.9 mm) orifice, which provides a broad umbrella of shielding gas, making it ideal for medium-to-high amperage applications where oxidation protection is critical. The 1/8-inch (3.2 mm) tip recess places the contact tip slightly back inside the nozzle. This recess is beneficial for short-circuit MIG welding as it helps prevent the contact tip from shorting against the workpiece and reduces the accumulation of spatter on the tip face. The body is machined from industrial-grade copper, chosen for its high thermal conductivity, which rapidly dissipates heat away from the front end, prolonging the life of both the nozzle and the internal insulation.

Thread-On Stability
A key advantage of the AccuLock S design is the thread-on mechanism. The nozzle threads directly onto the D-M250 diffuser, which features a steel retaining ring. This metal-on-metal engagement ensures concentricity between the contact tip and the nozzle orifice. Concentricity is vital for uniform gas flow; an off-center tip can lead to turbulent gas flow and porosity in the weld. Furthermore, the threaded connection prevents the nozzle from vibrating loose or falling off, a common annoyance with spring-loaded slip-on nozzles in heavy-duty environments.

Application & Compatibility
Designed specifically for the MDX-250, this nozzle is optimized for the 250-amp range. It is the standard replacement for the original equipment nozzle supplied with MDX-250 guns. Welders looking to maintain the original performance specifications of their torch or upgrade from standard consumables to the more robust S-series will find the N-A5818CM to be an indispensable component of their welding setup.