Milwaukee Tool 49-57-5308 Hex Rethreading Die 4-40 Unc

Product Description

The MILWAUKEE TOOL 49-57-5308 is a hex rethreading die designed to restore damaged or corroded external threads quickly in the field. Built from carbon steel, this die cuts right-hand threads to the 4-40 UNC standard, making it suitable for restoring small-diameter fastener threads common in electrical enclosures, control panels, and light mechanical assemblies. The hex body measures 1.0 inches across and follows the Hex-LOK series design, allowing it to seat securely in a standard rethreading die handle or wrench. At 0.07 pounds, it is compact enough to carry in a service bag without adding bulk. Electricians, HVAC technicians, and general maintenance mechanics reach for this die when a bolt or stud thread is too damaged to accept a nut but replacement is not practical.

This die is intended for use on 4-40 UNC threaded fasteners found in residential and light commercial equipment. Typical applications include restoring machine screw threads on control board mounting studs, panel screws, and small-frame electrical components. The fixed, non-adjustable design ensures consistent thread geometry with every pass, reducing rework on the job site. It is sold as a single die and is well-suited for technicians who carry individual dies matched to the fastener sizes common in their trade.

Key Features

• 4-40 UNC right-hand thread standard for compatibility with common small-diameter machine screws
• Carbon steel construction provides durability for repeated field use
• 1.0-inch hex body fits standard Hex-LOK die handles and wrenches
• Fixed, non-adjustable design ensures consistent thread depth and pitch on every pass
• Lightweight at 0.07 pounds — easy to carry in a tool pouch or service kit
• Hex-LOK series design seats securely to prevent slipping during operation

Compatibility

Designed for use with Hex-LOK series rethreading die handles and standard 1.0-inch hex die stocks. Restores 4-40 UNC right-hand external threads on machine screws, studs, and bolts.

Installation Notes

Rethreading dies are installed by a mechanic, electrician, or HVAC technician performing thread restoration on fasteners in place or removed from the assembly. Power down and de-energize any equipment before attempting thread repair on installed fasteners. Apply a thread-cutting lubricant to the die before starting to reduce friction and extend die life. Turn the die in small increments, backing off periodically to clear chips, following standard hand-tapping practice.