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

Packaging: pack of 2
$60.76/EA $86.82/pack of 2 only $43.41/EASave 29%

Usually ships within 3-5 business days

OVERVIEW

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.

Additional Information
Brand:Tweco
Item:Nozzle
Packaging Description:2 in a pack
Front End:Tweco
Bore Size:3/8" (9.5 mm)
Series:21 Series
Connection Type:Slip-On
Material:Copper Alloy
Compatible Guns:Tweco No. 1, Tweco No. 2, Tweco Mini-MIG
Part Number:21-37

INCLUDED

  • 2 x Tweco 21-37 Standard Slip-On Nozzles (3/8" Bore)

APPLICATIONS

  • Automotive Body Repair
  • Light to Medium Fabrication
  • General Maintenance and Repair
  • Hobbyist and DIY Welding
  • Sheet Metal Welding
  • Farm and Ranch Equipment Repair

FAQ

The Tweco 21-37 nozzle is designed to fit Tweco Classic No. 1 and No. 2 series MIG guns, as well as the Tweco Mini-MIG gun.

This nozzle has a 3/8-inch (0.375 inch or 9.5 mm) bore opening.

The Tweco 21-37 is a slip-on nozzle, which allows for easy installation and removal without threads.

This product (SKU 12101300) is a package containing 2 nozzles.

It is made of a durable copper alloy designed to withstand high heat and resist spatter.

Yes, you should use the standard gas diffuser/insulator compatible with Tweco 21 series nozzles and No. 1/No. 2 guns.

While you can physically use it, flux-cored welding (FCAW-S) typically does not require a gas nozzle. A gasless nozzle (thread protector) is often preferred to protect the threads and improve visibility, but this nozzle can be used if gas-shielded flux core is being applied.

A 3/8 inch bore is smaller, allowing for better access into tight corners and is generally suitable for lower amperage welding or smaller wire diameters where a massive gas envelope isn't required.