Understanding the distinction between thread milling and tapping is fundamental for machinists and metalworkers. Both methods produce threads that enable the screwing in of nuts, bolts, and other fasteners into metal parts. However, they differ considerably in their processes and applications. We’ll explain the difference between thread milling and tapping.
Thread Milling
Thread milling is a cutting process that uses a rotating tool to create threads in a hole. The cutter moves in a 3D spiral path, forming threads incrementally. This highly precise method allows for the creation of internal and external threads.
One of the biggest advantages of thread milling is its versatility. It’s suitable for various materials, large holes, and different thread sizes. All this is possible with the same tool. Thread milling offers excellent thread quality and tool life when properly cooled. Additionally, it is possible to mill threads very close to the bottom of a blind hole.
Thread milling is particularly suitable for hard materials that are difficult to tap. It shines when accuracy and repeatability are crucial, such as in the aerospace and medical industries. Large diameters and coarse threads are also where thread milling holds an edge.
The cost might be a limiting factor for thread milling, as the tooling required can be more expensive upfront. Moreover, it requires a machining center capable of helical interpolation.
Tapping
Tapping involves creating threads using a tool that cuts threads along the full length of the hole in a single pass. Machinists usually perform it on predrilled holes, and it’s possible to do manually or on a machine.
Tapping offers simplicity and speed, which is especially useful for mass production runs. It requires less powerful machinery, making it accessible for smaller workshops. Taps are relatively inexpensive and come in a vast range of sizes and thread pitches.
Tapping is ideal for softer materials and thinner workpieces. It suits applications where speed is more crucial than precision, such as general engineering and maintenance operations.
However, tapping may not be ideal when working with tough materials or if there’s a need for threads close to the bottom of a hole. Taps can also break more easily, potentially wasting materials and time.
Key Distinctions
Tapping is a single-pass process where a tap creates threads in a hole, while thread milling is a multi-pass process that uses a milling cutter to form threads gradually. Tapping is generally faster, but thread milling offers greater flexibility and strength in creating threads.
Regarding tooling costs, tapping often has lower costs because it requires a single tap, whereas thread milling may require multiple passes with a milling cutter. However, it’s important to consider the potential for breakage and waste with tapping, which can result in higher costs in certain scenarios.
When deciding between tapping and thread milling, you need to evaluate factors like the material used, the volume of pieces to thread, and the specific requirements of the threaded hole. Taking these details into account will help ensure you choose the most suitable thread creation method for optimal results.
Now that you know the difference between thread milling and tapping, you can select the best option for your project. Check out TMT Toolbox’s selection of thread tapping tools today. When you want higher precision and flexibility, thread milling is the way to go. If you’re looking for speed in softer materials and simpler applications, tapping is your process of choice.
