What Is Thread Milling?

Thread milling is a metalworking operation used to cut internal and external threads of different sizes through the circular ramping movement of a rotating tool. The thread pitch is created by the lateral movement in one revolution. Different from tapping, thread milling is mainly applied to larger workpieces, however, solid carbide thread mills can also produce small threaded holes. 

Thread Milling provides a better quality thread than tapping as it offers better chip evacuation. Tapping uses a tool the same size as the thread, forcing the chip through the thread for evacuation. Thread Milling tools are flexible. They can do internal and external threads, and can cut to different diameters, so long as the pitch is the same. You can carry out threading in difficult to machine materials. Due to the superior cutting conditions, they can thread hardened steels up to HRC 65, Titanium and even more! They are very secure due to producing short chips and having a low cutting force. The workpiece is less likely to get damaged as the diameter is smaller than the thread. Using a tool smaller than the thread ensures the thread is properly machined with the correct clearance needed to evacuate the chips effectively. 

One main advantage against tapping, is that tapping only starts making a complete thread profile on the third thread, whereas thread milling will produce a complete thread profile from the top to the bottom. The process can reduce machining time and save energy. High thread quality can be achieved without burrs. 

At Protool, we supply some of the best performing thread mill cutters in the UK. Shop our wide range of JBO Thread Mills today.