What are 3 types of taps?

The three primary types of taps used for cutting internal screw threads are taper, plug, and bottoming taps.

These taps are essential tools in various metalworking and machining applications, each designed for specific stages of thread creation, particularly in blind holes. Understanding their differences is crucial for achieving precise and complete threads.

1. Taper Tap

The taper tap is characterized by a visible and pronounced tapering of its cutting edges, typically extending for 7 to 10 threads. This design facilitates a very gradual and less aggressive cutting action, making it ideal for initiating new threads.

• Key Characteristics:
  • Longest taper among the three types.
  • Starts the thread cutting process, guiding the tap easily into the pilot hole.
  • Removes minimal material per revolution, reducing the risk of breakage, especially when starting threads in tough materials.
  • Often the first tap used, especially for through-holes or as the initial pass in blind holes.

2. Plug Tap

The plug tap (sometimes called a "second tap" or "intermediate tap") has a shorter, less pronounced taper, usually spanning 3 to 5 threads. It is designed to cut threads deeper into a hole than a taper tap, bringing the thread closer to its final depth.

• Key Characteristics:
  • Less taper than a taper tap, allowing it to cut threads further down.
  • Commonly used after a taper tap to deepen the threads in blind holes.
  • Provides a good balance between ease of use and thread depth.
  • Can be used as the primary tap for through-holes where a full thread is not required immediately at the top surface.

3. Bottoming Tap

The bottoming tap (also known as a "finishing tap" or "bottom tap") has almost no taper on its cutting edges, typically only 1 to 1.5 threads. Its primary purpose is to cut full threads to the very bottom of a blind hole after a taper or plug tap has created the initial threading.

• Key Characteristics:
  • Minimal to no taper, enabling it to cut threads all the way to the bottom.
  • Used as the final tap in a set to ensure complete thread depth in blind holes.
  • Should only be used in holes that have already been partially threaded by a taper or plug tap, as its lack of taper makes it difficult to start in an unthreaded hole.
  • Essential for applications requiring maximum thread engagement.

Comparative Overview of Tap Types

Choosing the right tap type or combination of taps ensures that threads are cut precisely, securely, and to the required depth, preventing damage to the workpiece and ensuring proper fastening.