Tweco 1040-1129 Mig Gun 400A 25 Ft Miller

Product Description

The TWECO 1040-1129 is a Professional No. 4 Classic Series air-cooled MIG gun rated at 400 amps with a 60% duty cycle using CO2 gas. Designed for semi-automatic MIG welding, it accepts wire sizes from 0.035 to 0.045 inches and ships with a 25-foot lead cable featuring a Miller-style rear connection. The conductor tube is a 60-degree metal jacket design with three-layer construction — copper tube, silicon-resin glass insulator, and outer metal jacket — for durability under sustained heat loads. The handle is an oval-shaped, high-impact crush-resistant plastic balanced to pivot at its center, reducing grip fatigue during extended use. Licensed HVAC and welding professionals in medium- to heavy-duty fabrication environments are the primary installers and operators.

This gun is suited for medium and heavy-duty fabrication, maintenance and repair, and production welding applications. The Miller-style rear connection makes it a direct replacement or upgrade option for shops already running Miller wire feeders. The fully insulated Mig-Kwik connection allows fast hookup and disconnection at the wire feeder, which shortens changeover time in production settings. The interchangeable front-end consumables are shared across the Tweco Spray Master series and Tweco Professional No. Series, reducing the variety of tips and nozzles a shop must stock.

Key Features

• 400A rating at 60% duty cycle with CO2 gas for sustained medium- and heavy-duty welding
• Accepts wire sizes 0.035 to 0.045 inches with a 25-foot cable for reach flexibility
• Three-layer conductor tube construction: copper tube, silicon-resin glass insulator, and metal jacket
• Silver-plated trigger contacts with self-cleaning action on every actuation
• Steel spring strain relief on the rear of the handle minimizes wire feed issues at the Cablehoz exit point
• Two ball-point screws secure the Cablehoz and conductor tube; split-half handle case allows field repair without additional connectors
• 60-degree metal jacket conductor tube swivels 360 degrees around the handle for quick replacement and positioning

Compatibility

Designed for use with Miller-style wire feeders via the Miller-style rear connection. Front-end consumables are interchangeable with the Tweco Spray Master series and Tweco Professional No. Series guns.

Installation Notes

Installation and setup should be performed by a qualified welding technician or industrial electrician familiar with MIG welding equipment. Power down and disconnect the wire feeder from its power source before connecting or disconnecting the gun. Verify that the wire feeder's drive roll groove matches the wire size in use before feeding wire through the gun. Follow the equipment manufacturer's guidelines and applicable ANSI or AWS safety standards when setting up or servicing MIG welding equipment.

Technical Specifications

• Amperage: 400 amps
• Duty Cycle: 60% with CO2 gas
• Wire Size Range: 0.035 to 0.045 inches
• Cable Length: 25 feet
• Conductor Tube Angle: 60 degrees
• Rear Connection Style: Miller
• Cooling Method: Air-cooled
• Package Length: 23 inches
• Package Width: 14.6 inches
• Package Height: 3.5 inches
• Weight: 17 pounds
• UPC: 608246012698

Standard Information

• Brand: TWECO
• Manufacturer Part Number: 1040-1129