The Turning Process (link off of screw machine processes page)

With the machining process known as turning, there is the use of a cutting tool, which is typically a non-rotary tool bit. This tool moves more or less linearly while the workpiece rotates. Typically, the creation of exterior surfaces by this cutting action is referred to as "turning." Whereas the creation of interior surfaces by this same fundamental cutting action is referred to as "boring."

The wider family of lathing processes is then categorized by the phrase "turning and boring." The term "facing," which may be included under either category as a subset, refers to the cutting of faces on the workpiece with either a turning or a boring tool. The act of turning can be performed manually, on a traditional lathe, which needs constant operator monitoring or on an automated lathe, which does not. The form of automation most frequently used today with lathes is computer numerical control (CNC).

To produce accurate diameters and depths during turning, the workpiece is rotated while a cutting tool is manipulated in 1, 2, or 3 axes of motion. The common workpieces in use include wood, plastic, metal and stone. Turning, also known as drilling, can be done on the interior of the cylinder or on the outside to create tubular parts with various geometries. Manufacturers can use this rotary machining technique to carry out a variety of operations on a component, which includes drilling, slotting, knurling, threading, and milling.

External Turning Operations

Some of the external operations include:

Hard Turning

Hard turning is performed on materials having a Rockwell C hardness of at least 45. It is usually carried after the heat treatment of the workpiece. This turning method aims to reduce or eliminate the need for conventional grinding processes. Rough grinding and hard turning are competitive when used for stock removal. However, grinding is best when finishing is the main use where the shape and dimensions are important.

Tapered Turning

A cylindrical form with a steadily shrinking diameter from one side to the other, which results from tapered turning.


An equal-width groove is carved by a single-point turning tool as it advances radially into the side of the workpiece. In order to create grooves that are wider than the tool width, several cuts can be performed. Specific form tools can be used to make grooves with different geometries.


A single-point cut-off tool will operate similarly to a groover, which moves radially into the side of the workpiece. And continuing until the inner or center diameter is reached, which divides or cuts off a portion of the workpiece.

Surfacing Metal Parts

Screw machining can be used to surface metal objects in addition to shaping them. A knurled finish or a smooth, nearly polished finish can both be produced via turning. The second spindle in a twin spindle CNC Swiss screw machine, which can perform secondary operations, as opposed to an actual operator.

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At Sesco Industries, we provide our customers with a wide range of aerospace parts. Parts that utilize the screw machining process in order to function properly. Request a quote today for any aerospace parts and products.

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When you reach out, we can provide you with all of the required information in order to make your purchase. Sesco Industries is a trusted aerospace parts supplier, with years of experience in the industry. Some other aerospace parts we sell include machine screws, NAS fasteners, and socket set screws. Learn more about other screw machining processes.