Internal threading is an elementary technique in manufacturing that produces the interior bore of a hole for the purpose of joining the elements. Whatever the size of the component –from light machine elements to heavy industrial plants, the internal thread comes in handy when thread tension is required for effective fastening. In this article, you will learn how internal threads are created and understand the techniques, equipment, and important aspects.
Methods of Making Internal Threads
Tapping
Of the different methods of producing internal threads, the most widely used technique is tapping. It uses a tool known as the tap that turns threads into an already drilled hole. Hand taps are of different types, namely straight taps, bottoming taps, and spiral point taps. These taps are further classified into two categories: hand taps and machine taps. For example, machine taps are used in automated production processes, and for faster and more efficient threading, hand taps are designed for use in manual or low-production volume processes.
Thread Milling
Another efficient technique for making internal threads is thread milling, especially in hard-to-machine materials. The method employed utilizes a thread mill, which is a rotary cutting tool with a number of teeth to develop the thread form. Thread tapping is a separate tool, and thread milling is carried out by a computer numerical control (CNC) machine, which has a lot of control over making the tool.
Forming (Roll Tapping)
Thread forming, also referred to as roll tapping, is one of the non-cutting processes of thread production. The shaping of polymers does not involve cutting them to form the required threads but rather distorts the material into the thread’s shape. This is done using a forming tap, which has a specific geometry to force material into the needed thread shape.
Tools Used for Internal Threading
There are a number of cutters that are specifically for creating internal threads, depending on the method and material employed.
Taps: As so stated, taps are among the most often used tools when it comes to cutting threads. It comes as high-speed steel(HSS) or carbide and may have some coating to improve performance.
- Thread Mills: Thread mills are useful cutting tools employed in CNC machines to perform internal threads with high accuracy. These tools are appropriate for situations where a thread form or material is non-conventional or very precise.
- Pipe Taps:Specialized pipe taps are employed to cut threads into the pipes to make quality fits for connecting to fluid. They are essential in any sealing application, especially in plumbing and hydraulic systems.
- Gauges:A number of applications indicate that internal thread gauges play an important role in the measurement and control of threads. They make sure that the thread engages specific tolerance and standards and that they are of the correct size.
Factors to Consider Internal Threadinging
Material Selection
The type of material being machined also plays a very big role in the threading method to be used. On harder materials, stronger materials like carbide taps are needed, while on softer materials, tools that are coated to avoid build-up on the tool’s surface are recommended. Secondly, ductile materials can be used for thread forming because their deformation does not lead to fractures.
Pre-Drilling
An accurate pilot hole is to optimize the formation of Internal threads; Their specification must be correct to achieve maximum results. Before inserting the screw, the size of the hole that is drilled first must be of the right size to accommodate the kind of thread size and pitch to be achieved. Forcing the drill to an undersized diameter will cause overuse of the tool, while using a large diameter will produce threads with little strength.
Cutting Fluids
The right cutting fluid is needed not only to extend the life of the tool but also to minimize heat and enhance the threaded fasteners. Specialty fluids are ones that have been custom-made for a particular material type of aluminum or stainless steel to enhance the performance of the fluid and eliminate galling or thread distortion.
Conclusion
Manufacturing internal thread is an invasive procedure that provides the elements with traction and exactness to bond in fastening ways. As mentioned in the previous section, each method of thread forming is beneficial in its own way and, therefore, is appropriate for various types of materials, sizes, and industrial applications. That is why, by choosing the right tools, checking the appropriate settings, and adhering to the rule of quality control, manufacturers can provide the creation of high-quality internal threaded products for various industries.
