Tapping threads
Thread Taps
thread taps are undoubtedly one of the most popular tools in the machine shop industry when it comes to manufacturing internal threads. These small but critically important tools enable the precise and clean cutting of threads into various materials. Cutting thread taps work by removing chips from the material, thus forming the desired thread in a hole. It is important to note that there are two main types of thread taps: bottoming taps and through taps. Each has its own special features, and their use depends on the specific requirements of the machining process.
Bottoming taps are equipped with a spiral fluted design, which is a particularly valuable feature. This flute allows the chips produced during threading to be lifted upward and out of the hole. This is especially important when threads are being made in holes that do not pass through the workpiece. In such applications, it is essential to remove the chips from the hole to maintain both the hole and the tap's condition. The spiral flute design of a bottoming tap enables efficient chip removal, making it an excellent choice for applications where the bottoms of holes are deep in the material and precise, clean threading is required.
Through taps, on the other hand, offer a solution for situations where the threaded holes pass through the material. These types of taps typically have straight flutes that help form short chips, which break easily and are expelled through the hole during work. This feature makes through taps an ideal choice for threading through holes, as it minimizes the need for chip removal from the hole and simplifies the machining process. Thanks to this type of tap, machining is efficient and chip management is easier, which improves production speed and quality.
Choosing between these two types of thread taps largely depends on the structure of the workpiece being machined and the characteristics required for the threads. Bottoming taps are ideal when ensuring that threads cut at the bottom of a hole are as clean and precise as possible. Conversely, through taps are an excellent choice when machining through holes and when aiming to optimize production time.
Regardless of which type of tap is chosen, it is important to remember that high-quality tools and careful machining process planning are key to achieving successful threading work. Cutting thread taps are a significant part of modern manufacturing technology, and their role cannot be underestimated in any machine shop or manufacturing process.
Forming Thread Taps
Forming thread taps, also known as roll taps, offer an alternative method for making internal threads. This method differs from traditional cutting threading as it does not remove material but instead forms the existing material into a new shape. Roll threading uses a specialized tool pressed through the hole to form the material into a thread. This process creates a remarkably strong and uniform thread, as the tool's pressure compacts the material, enhancing its durability and resistance to stress.
Advantages of form threading include producing threads with excellent dimensional accuracy and surface finish, as well as eliminating issues with chip removal and handling since the method does not remove material.
The threads formed by roll threading are more durable and reliable than those produced by traditional cutting methods, making it an excellent choice for applications requiring high strength and durability.
Thread Tap Attachment
Attaching thread taps to a machine tool typically involves using a synchronized tap holder, which includes a slight "micro-floating" movement range, approximately +/- 0.5mm. This tap holder enables better tool life and the production of higher-quality threads because the synchronized holder ensures that the threading tool remains in tight, consistent motion with the spindle.
Compared to the traditionally used quick-change floating tapping chucks, which allow a broader freedom of movement and are suitable for machines without precise spindle synchronization, synchronized holders offer tighter control. Additionally, they enable the use of internal high-pressure cooling systems, at best up to 80 bar pressure, improving tool cooling and effectively removing chips from the working area.
When attaching the tool, it is also essential to consider that when using fixed tap holders, such as an ER collet chuck, a specific ER collet designed for tapping must be used. This collet's square profile prevents the tool from rotating within the collet during threading, providing stable threading.
