Tweco 1240-1404 Mig Nozzle 3/8 Inch Bore 450A Coarse Thread

Product Description

The TWECO 1240-1404 is a coarse-threaded copper MIG welding nozzle designed for medium to heavy duty welding applications rated up to 450 amps. Machined from a solid 145 tellurium copper alloy bar, it delivers consistent dimensional stability and efficient heat dissipation during high-demand weld cycles. The nozzle measures 1.75 inches in length with a 3/8 inch (0.375 inch) bore and a 1.07 inch outer diameter. The two-piece design separates the nozzle housing from the nozzle insulator, allowing independent replacement of each component. The part number is rolled and stamped on the outer surface for fast field identification. Sold in a pack of 2.

This nozzle is used in medium to heavy duty MIG welding operations where consistent arc performance and thermal management are critical. The recessed contact tip relationship of 0.125 to 0.156 inches makes it suited for higher heat applications, longer electrical stick-out requirements, and situations where the nozzle may contact the workpiece during tack, spot, or stitch welding. It is rated for use with Tweco No. 4 MIG guns at up to 450 amps. The coarse thread pattern engages the nozzle insulator, which threads onto the conductor tube and provides electrical insulation between the nozzle housing and the gun body. The nozzle insulator and nozzle housing are sold separately from this listing.

Key Features

• Machined from solid 145 tellurium copper alloy bar for consistent dimensional stability and heat dissipation
• Coarse thread design threads onto a separate nozzle insulator for two-piece assembly
• Recessed contact tip relationship of 0.125 to 0.156 inches for high-heat and contact welding scenarios
• Part number rolled stamped on outer surface for easy identification in the field
• Rated up to 450 amps for medium to heavy duty MIG welding
• Sold as a pack of 2

Compatibility

Designed for use with Tweco No. 4 MIG guns rated up to 450 amps. Nozzle housing and nozzle insulator are sold separately and required for complete assembly.

Installation Notes

Installation is performed by qualified welders or MIG gun service technicians. Disconnect and de-energize the welding power source before replacing any front-end consumables. The nozzle housing threads onto the nozzle insulator, which must already be installed on the conductor tube before seating the nozzle. Inspect the conductor tube and insulator for wear or damage before installing new nozzle components.

Technical Specifications

• Bore Size: 0.375 inches
• Nozzle Length: 1.75 inches
• Outer Diameter: 1.07 inches
• Recessed Tip Relationship: 0.125 to 0.156 inches
• Current Rating: 450 amps
• Thread Type: Coarse thread
• Material: 145 tellurium copper alloy
• Design: Two-piece (nozzle housing and nozzle insulator)
• Weight: 0.13 pounds
• Sold As: 2 per pack

Standard Information

• Brand: TWECO
• Manufacturer Part Number: 1240-1404