Taper Taps

Taper taps have the longest thread chamfer, from 7 to 10 threads. They are particularly useful for starting threads, and tapping through holes |
Plug Taps

This style, witha a 3 to 5 thread chamfer, is widely used in through holes, and where there is enough room at the bottom of a closed hole. This is commonly a general purpose tap. |
Bottoming Taps

Bottoming taps have only a 1 to 2 thread chamfer. These are made to thread blind or "closed" holes close to the bottom of the hole |