12101300 - Tweco 21-37 Slip-On MIG Nozzle 3/8" Bore (2-Pack)

Tweco 21-37 Slip-On Nozzle (Stock #1210-1300)

The Tweco 21-37 (Internal SKU: TWE1210-1300) is a standard gas nozzle designed for use with Tweco Classic No. 1 and No. 2 MIG guns, as well as the Tweco Mini-MIG. This product comes in a convenient package of 2, providing professional fabricators with the necessary consumables to maintain continuous operations. Featuring a 0.375-inch (3/8") bore orifice, this nozzle is optimized for general-purpose MIG welding, offering a focused shielding gas envelope that is critical for protecting the weld pool from atmospheric contamination.

Engineered with the professional in mind, the 21-37 utilizes a slip-on interface that fits securely over the gas diffuser/insulator of the MIG gun. This friction-fit design eliminates the need for threads, which are prone to cross-threading or seizing due to thermal cycling and spatter buildup. The nozzle housing is machined from high-grade copper alloy, chosen for its superior thermal conductivity and durability. This ensures that the nozzle dissipates heat effectively, prolonging the life of the consumable and the front-end parts of the torch.

This nozzle is part of the Tweco 21 Series, which is widely recognized for its reliability in light-to-medium duty industrial applications. The 3/8" bore size is particularly effective for accessing tighter joints where a larger 1/2" or 5/8" nozzle might be too bulky, while still providing adequate gas flow for standard short-circuit MIG welding. It is compatible with standard gas diffusers used in the No. 1 and No. 2 gun series.

Technical Specifications

• Part Number: 21-37 (1210-1300)
• Bore Diameter: 3/8 inch (9.5 mm)
• Connection Style: Slip-On
• Material: Copper Alloy
• Compatibility: Tweco No. 1 (180A) and No. 2 (250A) MIG Guns
• Packaging: 2 Nozzles per Pack

Invest in genuine Tweco consumables to maintain the integrity of your welding equipment. The 21-37 nozzle ensures proper gas laminar flow, reducing the risk of porosity and ensuring high-quality weld beads in mild steel, stainless steel, and aluminum applications.