431-1890 - MK Products 7-Inch Jump Liner for Tweco Power Pins

Technical Overview of the MK Products 431-1890 Liner

The MK Products 431-1890 is a specialized replacement liner designed for use within Tweco-style power pin assemblies. Often referred to as a "jump liner" or "power pin liner," this component plays a critical role in the wire feeding system of push-pull MIG guns, such as the MK Cobra or Python series, when adapted for use with feeders requiring a Tweco connection. Measuring 7 inches in length, it is engineered to bridge the short distance inside the power pin adapter, guiding the welding wire from the feeder's drive rolls into the main conduit of the gun cable.

Proper maintenance of the power pin liner is essential for consistent arc stability. Over time, these short liners can become clogged with shavings or worn by the abrasive action of the wire, leading to increased friction and potential feedability issues like birdnesting. The 431-1890 is manufactured to precise OEM specifications by MK Products, ensuring perfect alignment and concentricity with the mating components. It is compatible with standard Tweco-style adapters used in conjunction with MK wire feeding systems.

Installation involves inserting the liner into the power pin assembly and, if necessary, trimming it to the exact length required for the specific feeder setup to ensure minimum gap between the liner and the drive rolls. This attention to detail in the wire path minimizes unsupported wire length, which is particularly important when feeding softer wires like aluminum.