Giving New Methods of Thread Cutting a Whirl

Machinists needing to produce parts with threads have many options for how to perform this operation. One of the most efficient processes is thread whirling, in which a circular toolholder with indexable insert cutters is mounted on an attachment that is canted to create the thread’s pitch. The blank is extended through the spindle or guide bushing, rotating at a low rpm. The cutting tool rotates around the blank, with each insert in turn cutting the thread into the blank.

The article “Two New Twists on Thread Whirling” takes a look at thread whirling and describes two variations on the process that promise to make it even more efficient. Horn’s “Turbowhirling” concept uses roughing and finishing inserts in the toolholder. The two types of inserts are specially designed to perform each task, improving tool life.

Rotary whirling is another take on thread whirling being developed by German Federal Ministry of Education and Research’s Thread Project, along with Horn, Index/Traub, medical device manufacturer Smith & Nephew and the research institute WBK Karlsruhe. In this method, a single-point turning tool traverses the blank ahead of the whirling cutter, removing material to take the blank down to the major diameter of the thread. The whirling tool only needs to take the part down to the minor thread diameter and produce the thread geometry. Because the whirling tool is removing less metal, cutting speeds can be increased. Read the article here.