N-A5814CM - Miller AccuLock S Copper Nozzle 5/8 Inch Orifice 1/4 Inch Recess

Precision Engineered for Industrial MIG Welding

The Miller AccuLock™ S Large Thread-On Copper Nozzle (SKU: N-A5814CM) represents a critical component in the high-performance AccuLock S consumable ecosystem. Designed specifically for industrial applications utilizing Miller MDX-250 MIG guns and Bernard BTB semi-automatic air-cooled guns, this nozzle is engineered to deliver superior gas coverage and thermal management. The unit features a substantial 5/8-inch (15.9 mm) orifice, which is optimal for applications requiring high gas flow rates to maintain a stable shielding atmosphere, particularly when welding thicker materials or utilizing spray transfer modes. The nozzle is manufactured from high-grade copper, a material selected for its exceptional thermal conductivity. This ensures that heat generated during the welding arc is rapidly dissipated away from the front end, significantly prolonging the service life of both the nozzle and the internal contact tip.

A defining feature of this component is its 1/4-inch (6.4 mm) tip recess. By positioning the contact tip deeper within the nozzle, the design provides an insulating buffer of shielding gas and distance that protects the tip from the intense radiant heat of the arc and minimizes the accumulation of spatter on the tip face. This recess is particularly advantageous in high-amperage scenarios where contact tip overheating can lead to burn-backs or erratic arc characteristics. Furthermore, the thread-on connection mechanism is precision-machined to ensure absolute concentricity. Unlike slip-on nozzles that can tilt or become misaligned, the AccuLock S thread-on design guarantees that the contact tip remains perfectly centered within the nozzle bore. This centering is crucial for maintaining a laminar gas flow pattern, which reduces turbulence and the likelihood of weld porosity caused by atmospheric contamination.

Integration with the AccuLock S system offers systemic benefits beyond the nozzle itself. The system is designed to capture the liner at both the front and back of the gun, preventing liner compression and ensuring a flawless path for the welding wire. When this nozzle is installed over the AccuLock S contact tip and D-MA250 diffuser, it completes a rigid, aligned assembly that promotes smooth wire feeding and consistent electrical conductivity. Industrial fabricators relying on the MDX-250 or Bernard BTB platforms will find this nozzle to be an essential upgrade for maintaining process reliability and weld quality standards.