42V75 - ESAB ST-21M MIG Gun Liner for 1/16 Wire

Technical Overview of the ESAB 42V75 Conduit Liner

The ESAB 42V75 Conduit Liner is a precision-engineered component designed to facilitate the smooth transfer of welding wire through the cable assembly of ST-21M series MIG guns. Specifically manufactured to accommodate 1/16-inch (1.6mm) diameter wire, this liner plays a pivotal role in the overall performance of the welding system. By providing a consistent, low-friction path from the wire feeder to the contact tip, it minimizes the mechanical resistance that can lead to feeding issues such as stuttering, burn-back, or irregular arc characteristics.

Constructed from high-grade wound steel monocoil, the 42V75 offers the ideal balance of flexibility and rigidity. This construction allows the liner to navigate the curvature of the gun cable without collapsing or kinking, which is essential for maintaining a constant wire speed during operation. Over time, liners can become clogged with copper flaking, shop dust, and other debris, or they may develop wear spots that increase friction. Replacing the liner with a genuine ESAB 42V75 restores the gun to its factory specifications, ensuring that the drive rolls can push the wire effectively without slippage or birdnesting at the feeder.

This component is critical for industrial applications where 1/16-inch wire is utilized for higher deposition rates. The liner's internal diameter is strictly toleranced to support the wire while preventing excessive play that could lead to wandering at the contact tip. Proper maintenance of the conduit liner is a fundamental aspect of welding equipment upkeep, directly influencing weld quality and operator efficiency. The ESAB 42V75 is the OEM-specified replacement, guaranteeing compatibility with the gas diffuser and gun handle geometry of the ST-21M model.