A Complete Guide on Types of Taps for Threading

What is threading, and why is it essential to know about the different types of taps for threading? To put it simply, threading is the process of creating helical ridges on the inside or outside of a cylindrical object. These ridges, known as threads, allow for the screwing in of bolts, nuts, and other fasteners. Taps are tools used to create these threads, and there are various types of taps designed for different threading needs.

Hand Taps

Hand taps are the most common type of tap used for threading. They are typically used for creating threads in small holes or in situations where power tools are not practical. Hand taps come in various styles, including taper taps, plug taps, and bottoming taps.

Taper taps have a more gradual cutting edge, making them suitable for starting threads in a hole. Plug taps have a slightly more pronounced cutting edge than taper taps and are used for threading to a moderate depth. Bottoming taps have a very short cutting edge and are excellent for tapping holes to the bottom.

When using hand taps, it is essential to use them with the correct tapping handle to ensure that the tap is held securely and straight. This will help prevent the tap from getting stuck or breaking during the threading process.

Machine Taps

Machine taps are designed for use with power tools such as drill presses, lathes, or CNC machines. These taps are typically made from higher quality materials and have a more precise cutting edge than hand taps. Machine taps also come in various styles, including spiral point taps, spiral flute taps, and thread forming taps.

Spiral point taps, also known as gun taps, have a spiral flute design that pushes chips forward as the tap moves into the hole. This design makes them suitable for through-hole threading. Spiral flute taps have the opposite design, with the flutes spiraling in the opposite direction, making them ideal for blind hole threading. Thread forming taps do not have cutting edges like traditional taps. Instead, they work by displacing the material to create threads.

When using machine taps, it is essential to use the correct speed and feed rate to prevent overheating and premature wear. Lubrication is also crucial to ensure smooth cutting and prevent chip buildup.

Pipe Taps

Pipe taps are specifically designed for creating threads in pipes and fittings. These taps have a tapered end to match the taper of pipe threads and are available in styles such as taper pipe taps, plug pipe taps, and bottoming pipe taps.

Taper pipe taps have a more gradual taper and are used to start threads in a pipe. Plug pipe taps have a slightly shorter taper than taper pipe taps and are used to cut threads to a moderate depth. Bottoming pipe taps have a very short taper and are used to tap threads to the bottom of a hole.

When using pipe taps, it is essential to use them with the proper cutting fluid to prevent overheating and ensure clean, smooth threading. It is also important to use a pipe tap wrench designed for use with pipe taps to prevent damage to the tap.

Specialty Taps

Specialty taps are designed for specific threading applications and are less common than general-purpose taps. These taps come in a variety of styles, including thread mills, interrupted thread taps, and pulley taps.

Thread mills are used for creating threads in materials where traditional tapping may be difficult or impossible, such as hardened steel or exotic alloys. Interrupted thread taps have special grooves that prevent the tap from binding in materials with interrupted or uneven threads. Pulley taps have a longer shank and are designed for tapping holes located deep within a workpiece, such as those in pulleys or gears.

When using specialty taps, it is essential to follow the manufacturer's recommendations for cutting speeds, feeds, and lubrication to ensure successful threading. Specialty taps are often more expensive than general-purpose taps, so it is crucial to use them only when necessary.

Thread Repair Taps

Thread repair taps are used to fix damaged or stripped threads in existing holes. These taps have a unique design that allows them to cut new threads next to the damaged ones, creating a fresh thread path for bolts or screws.

There are various types of thread repair taps, including helical coil taps, solid thread inserts, and thread chasers. Helical coil taps use a coiled wire insert to create a new thread in the hole. Solid thread inserts are threaded metal inserts that are installed into the hole to provide new threads. Thread chasers are used to clean up existing threads and remove any debris that may be causing the threading issues.

When using thread repair taps, it is essential to ensure that the damaged threads are cleaned and free of debris before using the tap. It is also crucial to use the correct size and type of thread repair tap for the specific threading problem.

In conclusion, understanding the different types of taps for threading is essential for anyone working with metalworking or other materials that require threaded connections. Whether using hand taps for small projects, machine taps for precision work, or specialty taps for unique applications, having the right tap for the job is crucial for successful threading. By following the manufacturer's recommendations for speed, feed, and lubrication, as well as using the correct tapping tools, you can ensure clean, accurate threads every time.