Deli 12Pcs Tap And Die Set Metric Wrench Cut Hand Threading Tool Tungsten Carbide Tap Die Screw Thread Making Tool Bit SetDeli 12Pcs Tap And Die Set Metric Wrench Cut Hand Threading Tool Tungsten Carbide Tap Die Screw Thread Making Tool Bit Set Taps and dies are tools used to create screw threads in all kinds of metalwork projects. 'Tap' is used to cut or form a thread on the inside surface of a hole creating effectively a nut, whilst a 'die' is used to cut or form matching bolts. Both tools can also be used, with a cutting oil, to clean up dirty, rusted, or worn threads