Threading

Thread manufacturing is an essential part of the machine-tool industry, since threads are a necessary feature in many machines and structures, providing detachable yet secure connections between components. Threads can be manufactured using a variety of methods, two of the most common being cutting and forming.

Cutting Taps

Cutting taps are among the most common tools used to produce internal threads. In this method, a cutting tap removes material to cut a thread into the hole. There are two main types of taps: bottoming taps and through-hole taps.

A bottoming tap is equipped with spiral flutes that allow the chips generated during the threading process to move up and out of the hole. This feature makes bottoming taps an excellent choice for applications in which the hole does not pass through the workpiece, making effective chip evacuation especially important. A through-hole tap, on the other hand, typically has straight flutes, which cause the chips to break into short pieces and exit through the hole. Through-hole taps are therefore particularly well suited for threading through holes.

Forming Taps (Roll-Forming Taps)

Another common method of producing internal threads is thread forming, also known as roll forming. Unlike the cutting method, thread forming does not remove material. Instead, a tool presses the material into the desired shape to form the thread in the hole. A thread formed in this way provides high dimensional accuracy and excellent surface quality. In addition, formed threads have a stronger structure, and the process does not involve problems related to chip evacuation.

Thread Milling

Thread milling is an effective method for producing both external and internal threads. This method can be performed using either solid-carbide thread mills or thread mills equipped with indexable inserts. Thread mills are particularly useful when machining large threads and hard materials. Thread milling also requires relatively little power from the machine tool and allows the thread size to be adjusted using the machine tool.

Producing External Threads

Several methods are used to produce external threads. Although high-speed steel thread dies are one way to produce external threads, this method is now primarily used for cleaning or restoring existing threads. The most common methods for producing external threads are thread turning and thread milling.

Thread Turning

Thread turning is a metalworking process that enables the production of complex thread profiles by turning. This process is important for manufacturing various threaded components, such as screws, nuts, and bolts. By using specialized turning tools, thread turning enables the precise and repeatable production of thread forms, which is essential in many industrial applications. To ensure quality and accuracy, advanced CNC lathes provide automatic control and high repeatability. When carefully controlled, thread turning can produce components that meet strict technical requirements, making it an essential technique in modern manufacturing. In thread turning, a turning tool corresponding to the thread profile machines the thread with a feed movement matched to the thread pitch. This method is particularly useful when precise dimensions and high surface quality are required.