a cutting tool used for repairing, cleaning, and restoring damaged external threads on bolts, rods, and shafts. It features internal cutting edges that re-form existing threads rather than creating new ones from raw material. Die nuts are commonly used in maintenance, automotive, mechanical, and engineering applications to remove burrs, corrosion, or thread damage and ensure proper fastener engagement. They are typically manufactured from high-speed steel (HSS) or alloy steel for durability, wear resistance, and accurate thread restoration.