Tweco 1240-1878 Heavy Duty Mig Nozzle 5/8 Inch Bore

Product Description

The TWECO 1240-1878 is a heavy duty MIG welding nozzle from the Velocity2a series, designed for professional welders who demand consistent performance and reduced downtime. Featuring a 5/8 inch bore, this nozzle uses a single-thread design that pairs brass threads on the nozzle against heat-treated stainless steel threads on the gooseneck. The soft-against-hard thread combination reduces seizing and cross-threading without requiring any tools for installation or removal. This nozzle is sold individually and weighs 0.27 pounds, making it a straightforward drop-in replacement in high-demand shop or field welding environments.

This nozzle is suited for MIG welding applications in both fabrication shops and field settings where heavy duty consumable life and thread reliability are priorities. The fixed threaded design maintains a consistent flush relationship between the nozzle opening and the contact tip, which helps stabilize arc performance across repeated use cycles. Welding professionals working with production runs or structural fabrication will benefit from the tool-free swap and single-thread interface that keeps changeovers fast.

Key Features

• Single-thread design eliminates two of the three thread sets found on typical MIG nozzles, reducing seizing and cross-threading
• Heat-treated stainless steel gooseneck threads resist wear and are built for long service life
• Brass nozzle threads grip securely against stainless and resist loosening under heat and vibration
• Tool-free installation and removal speeds consumable changeovers in production environments
• Fixed threaded configuration maintains consistent flush relationship between nozzle and contact tip
• Heavy duty construction rated for demanding MIG welding applications

Compatibility

Designed as an OEM-style replacement nozzle for compatible TWECO Velocity2a series MIG welding guns requiring a 5/8 inch bore heavy duty nozzle.

Installation Notes

Installation and replacement of MIG nozzles should be performed by a qualified welder or welding technician with the wire feeder and power source fully de-energized before service. Allow the nozzle and contact tip to cool completely before handling to avoid burns. Thread the nozzle by hand to avoid cross-threading, and confirm the nozzle is seated flush before resuming welding operations. Follow all applicable AWS safety guidelines and equipment manufacturer recommendations during consumable replacement.

Technical Specifications

• Bore Size: 5/8 inches
• Series: Velocity2a
• Duty Rating: Heavy Duty
• Thread Material (Nozzle): Brass
• Thread Material (Gooseneck): Heat-treated stainless steel
• Length: 2.25 inches
• Width: 1 inch
• Weight: 0.27 pounds
• Unit of Measure: Each
• Minimum Order Quantity: 2

Standard Information

• Brand: TWECO
• Manufacturer Part Number: 1240-1878