What is Tapping?
Tapping is the process of cutting the thread inside a hole for a cap screw or bolt to be threaded into the hole. The process also can be used to make a thread on nuts. The cutting tool used to create the thread in a hole is called Tap which has cutting edges in the shape of threads. The tap removes unwanted metal and cuts internal thread when it is screwed into the hole. Tapping can be done on the lathe machine, milling machine, tapping machine, or by hand. It is very important that you are using the proper size tap drill for the tapping and chamfered at the end. There are a variety of taps available to match different types of screws. You should choose the right tap based on the type of hole you want to thread. There are two classifications of taps, which are hand taps and power taps. Hand taps are considered the most common types of tap which include taper tap, plug tap, and bottoming tap. Power taps are used for CNC application or manual machining work, including spiral point tap, spiral flute tap, roll tap, etc.
The differences between Tapping and Drilling
Drilling and tapping belong to two different operations. As we mentioned before, tapping is to create a thread inside the hole. While drilling is using drills and motors to create a hole in a material.
The differences between Tapping and Threading
The process of cutting thread using a tap is known as tapping, while the process that uses die to create a thread is known as threading. Tapping is usually used to produce internal threads of a nut, and threading is used for creating external threads outside of the bolts. Additionally, a single tool is enough for the threading process, whereas different sizes of holes to be threaded require different size tap in the tapping process. Switching tapping tools for different size holes also increase the cycle time. Tapping has an advantage on the speed while threading is more flexible and able to control the thread fits.
Common Types of Tapping Tools
The choice of tapping tool depends on the type of hole and material that you want to thread. Taps are normally made of carbon tools steel or high-speed steel. Hand taps have short square-ended shanks that can be used for both machine and hand tapping. For hand tapping, the tap is screwed into the hole with the use of a tap wrench. If there is a large number of holes needed to be tapped, machine tapping becomes the ideal choice. Machine tapping can be done on the drill press with special tapping attachments.
Hand taps cover a set of three which are taper tap, plug tap, and bottoming tap.
- Taper tap is the most commonly used tapping tool as a starter tap for blind holes. They can be easily identified by pronounced and visible tapering of the cutting edges. Taper taps offer a very gradual and less aggressive cutting operation that allows for a straight hole to be cut in. The distinct feature of a taper tap is its 7 to 10 thread chamfered.
- A plug tap has 3 to 5 thread chamfered that can give a gradual cutting action that is more aggressive than the taper tap but less aggressive than the bottoming tap. Plug taps are suitable to be used for through-holes as they are easy to start with and provide a more complete set of threads than a taper tap.
- Bottoming tap only have 1 to 2 thread chamfered. They are best used after the initial thread has been cut with a taper or plug tap.
Spiral Flute Taps
Spiral flute taps are the preferred tool for cutting through soft metals or metal that will not chip. They work like the traditional drill bit that promotes the removal of cut material from the hole. They are also suitable for tapping blind holes. However, spiral flute taps are not as strong as hand taps so it is not recommended to be used for high hardness steel that is over 45 HRC.
Straight Flute Taps
Straight flute taps are strong cutting tools with flutes and have a larger cross-section of the cutting edges that are a great choice for cutting a thread into the hard material. But it requires more patience when using the tool, especially cutting and cleaning thread in the blind hole. Chips that build up below the straight flute tap are likely to lead to breakage and less clean-cut on threads.
Tips for Tapping Process
1. It is important to create a straight and usable tap. When tapping on the lathe or milling machine, the tap is centered and straight automatically. But when you do it manually, it is crucial to use tap guides located with the taps to create a straight tap as human eyes are not as accurate as of the tap guide on centering and straightening the tap.
2. Oil is essential during the tapping operation as it can clean out the chips, prevent overheating, and assist the overall cutting process. Don't forget to add oil before tapping.
3. You will also need a center drill when creating a tapped hole, especially aligning a larger bit to a center. This is because most drill bits aren’t perfectly centered and the center drill can make sure the larger bit will drill correctly that won’t walk across the part.
4. Always remember not to apply an excess downward force that may cause tap breakage. A rational force and pecking method are suggested to avoid tap breakage.
MecHero Malaysia supplies different types of tapping tools for your tapping process. You can always contact us at +6011-7000 7687 or email us at email@example.com for an inquiry about the tapping tools in Malaysia. As a steel and online hardware store in Malaysia, we also supply a wide range of steel materials, general hardware, or mechanical components. Tell us your requirements now and we can advise you accordingly.
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