21749 - ESAB MT-140 Replacement Liner 12ft .023-.030 Wire

Technical Overview: ESAB 21749 Liner for MT-140

The ESAB 21749 is a specialized replacement liner designed for the MT-140 series of MIG welding guns. This component is critical for the proper maintenance of the wire feeding system, acting as the conduit through which the welding wire travels from the drive rolls to the contact tip. It is engineered to accommodate solid steel wires with diameters ranging from 0.023 inches (0.6 mm) to 0.030 inches (0.8 mm), providing the precise internal clearance necessary to minimize friction while preventing wire buckling.

Constructed from high-tensile wound steel, this liner offers excellent flexibility and durability. The 12-foot length is tailored to fit standard MT-140 cable assemblies, though it can be trimmed to exact length during installation if required. A degraded liner is a leading cause of erratic arc performance and feeding issues; replacing it with the correct OEM-specification part ensures that the welding parameters remain consistent. This liner is particularly effective in general fabrication environments where small diameter wires are used for sheet metal or light structural work.

Installation of the 21749 liner restores the mechanical integrity of the gun's feed path. By maintaining a smooth internal surface, it reduces the drag coefficient on the wire, thereby reducing the load on the wire feeder motor and preventing slippage at the drive rolls. This component is an essential spare part for operators utilizing the MT-140 platform for MIG (GMAW) applications.