KP2742-1-38S - Lincoln Magnum PRO 350A MIG Nozzle 3/8 Bore 1/8 Stickout

Technical Specifications and Operational Benefits

The Lincoln Electric KP2742-1-38S is a standard-duty gas nozzle engineered for the Magnum PRO 350A MIG gun platform. It is designed to facilitate efficient gas shielding in semi-automatic welding processes ranging from short-circuit to spray transfer modes. The nozzle is constructed with a heavy-duty copper alloy base for superior thermal conductivity, which is then nickel-plated. This plating is not merely aesthetic; it serves a functional purpose by significantly increasing the surface hardness and reducing the adhesion of weld spatter. This feature is particularly beneficial in high-amperage applications where spatter generation is more prevalent, allowing for easier cleaning and longer service life compared to unplated copper nozzles.

Geometry and Fitment
The nozzle features a 3/8-inch (9.5 mm) bore, which is narrower than standard 1/2-inch or 5/8-inch nozzles. This reduced diameter is advantageous when welding in confined spaces or tight corners where a larger nozzle would obstruct the welder's view or fail to fit. The 1/8-inch (3.2 mm) stickout configuration means the contact tip is recessed 1/8 inch inside the nozzle. This recess provides a mechanical shield for the contact tip, reducing the likelihood of the tip shorting against the workpiece and offering protection from radiant heat. It is ideal for applications where the contact tip to work distance (CTWD) needs to be closely managed.

Thread-On Mechanism
The KP2742-1-38S utilizes a coarse thread design for attachment to the diffuser. This design choice is critical for industrial environments. Fine threads can easily cross-thread or seize due to thermal expansion and contraction cycles. The coarse threads on the Magnum PRO series are robust and resist seizing, ensuring that the nozzle can be removed easily for cleaning or replacement even after prolonged welding sessions. It is important to note that this nozzle is compatible only with 350A thread-on diffusers and will not fit slip-on style front ends or 550A series guns.

Application Suitability
Rated for 350 amps at a 60% duty cycle (depending on the gun rating), this nozzle handles wire sizes from .035" up to 5/64". It is suitable for use with mixed gases and 100% CO2. The concentricity provided by the threaded connection ensures laminar gas flow, minimizing turbulence and the risk of atmospheric contamination in the weld pool.