Single Point Threading

What is Single Point Threading?

Threading, in general, refers simply to cutting threads on a work-piece. By far the most common use for threads is in making screws and bolts. The pattern of ridges and troughs on a screw is an external thread; the one on the inside of a bolt is an internal thread.

Single Point Threading indicates a particular technique used to create those threads. In single point threading, a solitary cutting head, often attached to a lathe, moves linearly or horizontally to a workpiece which is rotating.

As the single cutting point moves down the length of the screw, it removes material to create the threads. The movement speed of the cutter and the rotation speed of the screw also work together to determine the depth of the threads and how tight or close together they are.

In theory, single point threading can be used to create any threading on any part, internal or external, large or small. This one technique alone could be used to create all the screws in the world, which is significant: screw threads are the single most-produced element of machinery each year.

In reality, single point threading is one of a number of potential techniques for cutting screw threads. Single point threading removes material, as does milling; both are known as subtractive methods.

Screw threads can be created also by transformative methods, such as molding, forming, or rolling, or by additive methods like 3D printing. But single point threading remains a common method used to cut screw threads.

Industrial Applications

Single point threading, like so many other industrial technologies, has been vastly improved and made more efficient through the introduction of CNC technology. Starting in the mid-1970s, CNC-equipped lathes allowed operators to input “canned programs,” endlessly-repeatable instructions for CNC machines to produce a near-constant stream of screws.

Formerly, the process relied on trained manual operators, who needed to track both the speed at which the spindle and cutting head rotated and the speed of the workpiece. With CNC programming, today’s machines track both speeds automatically, keeping the lathe in perfect synch. 

Some of the other thread-cutting methods, such as tap and die, are more cost-effective for high-volume pieces. For manufacturers producing hundreds of thousands of screws for a particular machine, single point threading may not be cost-effective.

However, the technique remains highly useful in circumstances where only a handful of threaded pieces are needed, such as unavailable replacement parts or specialized, one-of-a-kind machinery. For small-volume pieces, single-point threading on a CNC-equipped lathe proves highly useful.

Further Resources

Looking for more information? Below are some helpful links to demonstrate more about single-point threading.