Taper Tap

A taper tap has quite a lot of taper to help it ease into cutting threads gradually.   Typically, the first 8 to 10 threads are tapered.  Taper Taps are the most common types of taps and are typically what you’ll have in a Tap and Die Set.

Bottoming Tap

A bottoming tap has almost no taper at the end because it is designed to thread all the way to the bottom of its reach.  Only 1 to 1.5 threads will be tapered.

Bottoming Taps are useful for threading blind holes.  It’s desireable to thread most of the hole with a Taper Tap first, and then finish the bottom of the hole with a Bottoming Tap.

Plug Tap

Plug Taps are in between Bottoming and Taper Taps because they have 3-5 threads tapered, which is more than a Bottoming Tap and less than a Taper Tap.