Emuge - 1/2-20 UNF 4 Flute 2B Modified Bottoming Spiral Flute Tap - Cobalt, Oxide Finish, 3-3/8" OAL, Right Hand Flute, Right Hand Thread

Modified bottoming chamfers are similar to bottoming chamfers, but they are longer and have more teeth. They are used for threading blind holes and have 2 to 2-1/2 threads.

Cobalt is harder than high speed steel and provides better wear resistance. It is commonly used on high tensile alloys.

Oxide, also known as black oxide or steam oxide, is a surface treatment that prevents chip building, galling and welding on the workpiece. It is commonly used on low carbons, stainless steel and ferrous metals.