N-M58XTC - Miller AccuLock MDX Thread-On Nozzle 5/8" Bore 1/8" Stickout

Technical Overview of the Miller AccuLock MDX N-M58XTC Nozzle

The Miller N-M58XTC is a premium copper MIG welding nozzle designed as an integral component of the AccuLock™ MDX™ consumable system. Engineered specifically for the MDX-250 and MDX-250 EZ-Select™ MIG guns, this nozzle addresses common failure points in industrial welding environments: thermal loosening and wire feed misalignment. The nozzle features a 5/8-inch (15.9 mm) orifice, which is the standard size for general-purpose fabrication, providing an optimal balance of shielding gas coverage and accessibility. The 1/8-inch (3.2 mm) tip extension, or stickout, allows the contact tip to protrude slightly beyond the nozzle face, enhancing arc visibility and allowing for tighter access in fillet welds.

A defining technical feature of the N-M58XTC is its thread-on connection mechanism reinforced with a steel retaining ring. Unlike traditional slip-on nozzles that rely on friction springs or O-rings—which can degrade under high heat—the AccuLock thread-on design maintains a rigid mechanical connection to the diffuser. This ensures the nozzle remains concentric and tight even during prolonged welding cycles at high amperages. The copper construction facilitates rapid heat transfer away from the front end, prolonging the life of both the nozzle and the internal contact tip.

The AccuLock MDX system itself is designed to optimize wire feeding. When this nozzle is installed, it works in conjunction with the AccuLock contact tip and diffuser to center and lock the liner in position. This concentric alignment creates a flawless path for the welding wire from the feeder to the weld pool, significantly reducing drag and the likelihood of bird-nesting or burnback. For maintenance, repair, and operations (MRO) professionals, this translates to reduced downtime for consumable changes and troubleshooting.

This nozzle is compatible with the standard MDX-250 MIG guns found on machines such as the Millermatic® 212, 252, 255, and Multimatic® series when equipped with the MDX-250 platform. It is not compatible with the smaller MDX-100 guns or the heavy-duty industrial AccuLock S series, ensuring that users must verify gun model compatibility before procurement.