Tap Die Set: M3 x 0.5 metric tap and die set can make new threads or re-thread damaged or jammed threads, good for general purpose applications. Clear threads without burrs, left hand (reverse) tapping direction. Applications: The round die can process, correct or clean the external threads. The thread tap is suitable for processing through hole or shallow hole female threads. Suitable for tapping stainless steel, aluminum alloy, cast iron, copper, iron, aluminum, plastic in maintenance and repair work. Features: High speed steel straight flute tap provides rapid downward chip removal for efficient threading, with combination of hardness and toughness for wear resistance. Alloy tool steel die is with conical locking hole, strong locking, not loose, hardness, high torque, good toughness and wear resistance. Easy to Use: Round dies can be used with die wrench (not included). The fastening screw in the middle of the wrench should be inserted into the slot of the die and tightened. Machine taps are used on drill presses, tapping machines, CNC and milling machines. Tips: Used with tapping oil can get higher quality threads and make taps and dies more durable. Suitable lubricating oil should be added to the cutting edge of dies and taps when tapping. It needs to be reversed every 1/4~1/2 turn to facilitate the chip discharge from the die chip hole.