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3 Different CNC Machining Options

Updated: Apr 25, 2022

The Most Common CNC Machining Options: Turning, Milling, and Screw Machining

When it comes to CNC Machine cutting tools there are a few different manufacturing processes that can be utilized depending on the desired geometry of your custom part and the estimated annual usage (EAU).

Here are the most common CNC Machining processes:

  • Turning

  • Milling

  • Screw Machine

CNC Turning Services

Lathes are utilized to perform the turning process. A Lathe is a machine cutting tool that rotates (turns) the desired material on its horizontal axis while being shaped by a cutting tools.

One of the first truly precision lathes was designed and built during the Industrial Revolution in 1804 by Henry Maudslay. His Lathe is still on display at the Henry Ford Museum.

Two photos of Henry Maudslay's Screw-Cutting Lathes. The top photo is of what is ostensibly Henry's first design dated about 1797. It looks fairly primitive compared to the later more advanced design featured in the bottom photo dated about 1800
By Unknown photographer - Roe, Joseph Wickham (1916), English and American Tool Builders, New Haven, Connecticut, USA: Yale University Press, LCCN 16-011753. Reprinted by McGraw-Hill, New York and London, 1926 (LCCN 27-024075); and by Lindsay Publications, Inc., Bradley, IL, USA (ISBN 978-0-917914-73-7). Google Books URL is, Public Domain,

Drawing of an early screw-cutting lathe
Concept of an early Screw Machine

Laths can hold tight concentricity, close tolerance, complex features and providing a fine finish.

A CNC Lathe can be used to produce parts from solid bar stock, or it can be used to further machine a near net shaped part, a near net shaped part could be a forging, casting, or a previously machined bar stock part.

Processes Preformed on a Lathe

  • Turning

  • Form Turning

  • Taper Turning

  • Threading

  • Tapping

  • Thread Rolling

  • Thread Grinding

  • Thread Milling

Lathe Part Examples

  • Shafts

  • Nuts

  • Pistons

  • Ball Stud

CNC Milling Services

CNC Mills are utilized to perform the milling process. Milling machines can be both vertical or horizontal machining centers. A vertical mill is typically where the cutting tool comes from above and is lowered to the part. A horizontal Milling machine is when the cutting tool comes in from the side.

The milling machine was invented circa 1818 by Eli Whitney. An interesting fact about his machine is that it was so ahead of its time that most of the features and functions did not change for over a century and a half.

Drawing of an antique Milling Machine
Drawing of an antique Milling Machine

A CNC Mill generally works with solid plate or near net shaped parts from casting, forging or previously machined parts.

Processes Performed on a Mill

  • Milling

  • Drilling

  • Boring

  • Reaming

  • Gun Drilling

  • Broaching

  • Gear Hobbing

  • Splining

  • Keyways

Milling Part Examples

  • Flywheels

  • Piston Rods

  • Housing

  • Blocks

Screw Machine

A Screw Machine is a high-speed automatic lathe design to manufacture smaller high-volume parts.

The Screw Machine was invented by Joseph Brown in 1865. Brown was one of the co-founders of Brown and Sharpe. Brown and Sharpe screw machines are still sold and used today. Brown and Sharpe assets were acquired by Hexagon in 2001 and most of the newer equipment is now marketed under the Hexagon name.

Screw machines are best known for holding tight tolerance as well as being high speed work horses. These machines are best suited for higher volume parts with detailed geometry.

For lower EAU parts, a single spindle machine is generally used. When the volume is higher a multi-Spindle machine is utilized. If your part is designed correctly, this is a cost-effective machining process.

Processes Performed on a Screw Machine

  • Form Turning

  • Drilling

  • Reaming

  • Tapping

  • Cross Milling

Screw Machine Part Examples

  • Shafts

  • Push Rods

  • Gear Blanks

  • Spacers

  • Valve Stems

  • Screws

  • Plugs

Locke-Brothers has partnered with National Technologies (aka. “NTI”) since 2004. As a precision machining company established in 1959, NTI focuses on “Making it Better in America". They are a preferred supplier of precision machined components and assemblies for original equipment manufacturers worldwide.


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