Uxcell 1/4-20 Unc Tap And Die Set With 20Mm Round Die Stock Handle Wrench, High Tap and Die Set: 1/4-20 UNC thread tap and round die. 20mm die stock fits 11mm-20mm / M3-M4 capacity, with adjustable screws. Suitable for making or repairing male and female threads. Good for general purpose applications. Application: Can re-thread existing threads in hard materials like metal, or make new threads in soft material like plastic. Used to process mild steel, aluminum, stainless steel, iron, cast iron, alloy steel, and hard plastics, etc. Special Design: High-speed steel machine tap is with high hardness and toughness for wear resistance. Features just the base substrate without any additional coatings. With adjustable screws, the die stock can securely hold round dies Easy to Use: The positioning groove of the die should be aligned with the fastening screw in the middle of the die wrench, and the screw should be inserted into the slot of the die and tightened. Tips: It needs to be reversed every 1/4~1/2 turn to facilitate the chip discharge from the chip hole. Suitable lubricating oil should be added to the cutting edge of the die when tapping threads.