The three types of taps are:
1. Taper tap
2. Plug tap
3. Bottoming tap
To produce an internal thread, the taper tap is the first tap to be used because of its ease in entering the hole to commence the threading. Followed by the plug tap and finally the bottoming tap which give the thread the direct pitch, crest and root diameter. The plug and bottoming taps are generally used in a situation where the thread is not a through thread.