What is the difference between a taper and a plug tap?Taper taps are often called "starting" taps because they have more chamfered threads. The chamfer is the angled portion at the front of the tap which helps it start threading. Taper taps have 7 to 10 threads of the chamfer. Plug taps have 3-5 threads of the chamfer. The Taps is made of high-speed steel, which Rockwell hardness is up to HRC58, and excellent for tapping metals such as aluminum, copper, iron, wood, plastic, and so on. Specifications:Material: High Speed Steel(HSS)Rockwell Hardness: HRC.58Size: M3,M4,M5,M6,M8,M10,M12,M14,M15,M16,M18,M20 6Pcs M3-M10=M3,M4,M5,M6,M8,M10 11Pcs M3-M20=M3,M4,M5,M6,M8,M10,M12,M14,M15,M16,M18,M20 Quantity: 2Pc.=Taper Tap + Plug Tap How to use itTo start cutting inside threads lube your hole with cutting oil and start the taper tap with lots of taper run this tap about 2 or 3 turns in then back it out 1/4 turn lube your work go another 2 or 3 turns back it out 1/4 turn keeping your work wet with cutting fluid continue this method until you have completed the cut then use plug tap the tap with the 2nd least amount of taper run this tap through using the same method as above. Care in tapping:Considerable care must be exercised when tapping.Use the tap before they die because the tap is non-adjustable for size, the dies are.Start the tap square.Use a cutting solution where necessary.