CNC Turning: A Comprehensive Guide

Introduction to CNC Turning

CNC turning spins a workpiece in a chuck, while a stationary tool is then brought into contact with the material to create a cylindrical part. Popularised decades ago in the watchmaking industry, today’s CNC lathes are highly capable production centres with additional axes and the ability to increase manufacturing productivity.   

CNC turning differs fundamentally from milling. Milling can be described as a versatile machining strategy in which a rotating tool cuts a stationary workpiece. With turning, the applications are more specific, and the strategy is reversed: lathes spin the workpiece while the tool remains stationary. 

Basics of CNC Turning

The first lathes were hand-operated, but modern manufacturing has used CNC turning since the 1950s.  Here, a computer (controlled through an HMI) dictates the movement of the workpiece, eliminating a chunk of human error.

Like other machining technologies, CNC turning has undergone many advancements over the years. Most notably, automation and robotics have given the lathe more and more control over the manufacturer of parts. 

INDEX’s Multi-Spindle lathes were a huge leap for the technology, and we proudly champion their unmatched productivity.

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Typical Turning Centre Components

Types of CNC turning machines

The most common styles of lathes are listed below:

Turret Lathe 

A turret lathe has all of its tools located in an indexable turret; these turrets can hold multiple tools that are then swung into position when required.

Turning Centres 

Turning centres come in both vertical and horizontal configurations. Vertical machines can turn large, heavy parts, whereas horizontal machines are best suited to smaller, high-production components.

Sliding Stock Lathes 

Also known as Swiss lathes, these machines are extremely advanced and best suited to creating small repetitive parts with very high precision. They often have fixed tools and live tools that allow for unmatched cycle times.


Mill-turns are hybrids of milling machines and turret lathes. They have all the features of a typical turret lathe, with the added benefit of live tooling and an additional axis.

Advantages of CNC turning 


A CNC lathe can manufacture components at a very high rate. This is especially true for sliding stock lathes, which can engage the stock with multiple tools at once. 

Some lathes even have multiple primary spindles that can engage up to six stock pieces with multiple tools. Not even the most advanced CNC mills can match the speed with which a sliding stock lathe can churn out parts.


CNC lathes come in multiple configurations and can match any requirement, from pure OD and ID turning to combinations of turning, off-axis drilling, and even milling all in one machine. This results in the capability to run ‘done-in-one’ operations with ease.


A CNC lathe can operate non-stop due to automatic material loading bar feeders. This means that the operator only needs to make sure the machine is continuously fed with material, and it will continue to machine parts.

Lathe Axis

Like CNC mills, CNC lathes can be configured in various ways, best expressed in terms of their axes of movement.


A typical lathe has only two axes, the x and z axes. The z-axis is along the axis of the stock and the x-axis is perpendicular to the axis of the stock.


A mill-turn is a type of lathe and mill hybrid. These machines have the usual two axes of a standard lathe with additional Y and C axes. The C-axis refers to the primary spindle, which can be switched over to servo control and positioned accurately for a live tool that then moves along the Y-axis. Here, various slots and flat sections can be milled on the part.


An automatic sliding stock lathe can have as many as nine axes, sometimes more. This large number of axes is due to multiple tool posts, secondary spindles, and bar feeders, each of which can move in various directions. These highly advanced machines can create parts at incredible speeds and accuracies.

What is the CNC Turning Process?

At a basic, fundamental level, the CNC turning process follows four basic steps:

  1. Programming

Machinists and engineers convert CAD models to CNC programmes, which tell the turning centre the necessary machining parameters. 

  1. Setup

Raw material in the form of a metal bar is loaded into the chuck either manually or through automated processes. Cutting tools will need to be chosen and loaded into the machine here as well. 

  1. Turning

The CNC program will then rotate the workpiece at high speeds, while the cutting tool removes material. 

  1. Inspection

Once the finished component is removed and inspected, the lathe is free to move on to the next job.

Materials in CNC Turning

Like any other machining process, materials and their properties can greatly impact the turning process. 

Harder metals like super-alloys require specialised tools and specific cutting speeds, which can hamper production speed, while softer, gummier metals like aluminium can warp and heat up easily.

The individual properties of metals you turn will need careful attention.

Check out our popular machining guides for further advice

Quality and Efficiency in CNC Turning

The quality of turned parts hinges on three key factors:


CAD models and toolpaths need to be optimised and accurate for parts to be made correctly.

Machines and tooling

High-quality machines, like those we offer from INDEX Traub, paired with appropriate tools are vital for quality. Knowing how best to use your turning centre is also key here.

Workholding and process control

How your part is held, and how you go about machining it, is make-or-break for your part’s tolerances. Coolant, chip and swarf control, in-process checks and feed rates need to be planned without mistakes.

What about efficiency?

The most efficient machining processes master the three factors listed above, while also minimising downtime.

At Kingsbury, we always strive for processes that are constant, consistent and accurate. In short, the most efficient turning machines run most, if not all of the day, without scrap or wastage.

To achieve this, automated material handling systems are vital, as are training and continuous process improvement.

Applications and Industries


Automotive manufacturers rely on CNC turning for engine parts (pistons), transmission components (shafts), and suspension parts.

Aerospace & Defence

The engine and turbine components found in these industries are often made through turning. Defence in particular often relies on cylindrical parts produced to high tolerances.


Medical instruments, implants and other decides demand unwavering precision, so manufacturers often turn to CNC lathes to get the job done.

Energy, oil & gas

Rigs, refineries and power stations are common places to find CNC turned parts.


Modern electronics often contain high-tolerance, precise CNC turned components.


Similar to the aerospace & defence sector, marine engines and communication equipment rely on CNC turning.

Which CNC turning machine is right for you?

If your company focuses primarily on the manufacture of cylindrical components, then a turning lathe is the best machine for you. 

As there is a vast range of lathes available, choosing the correct one that best suits your application can be a relatively daunting task. Kingsbury offers a wide range of lathes that can fit any application.

CNC Turning Machines

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