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What Is Machining?

B. Turner
B. Turner

Machining is a form of manufacturing used to create objects out of metal. During this process, workers cut away materials to alter the appearance and shape of a product. Machining serves as an alternative to other forms of production processes, including molding or casting. It is one of the most effective methods of creating very fine, detailed objects, which are often not feasible through casting and molding techniques. Machining can be used to make everything from steel fasteners to metal jewelry, as well as larger objects like hand tools and automotive components.

This metalworking technique actually involves many types of processes that can be used to give metal the desired shape and finish. These techniques are often divided into four categories, and may be used together to produce a single product. Drilling is one of the most basic types of machining. During the drilling process, workers use a metal bit to cut holes in the metal. For example, drilling may be used to cut holes for fasteners in a metal kickplate used to protect a door.

Machining creates objects out of metal.
Machining creates objects out of metal.

Turning is another form of machining used to shape metal. During turning, metalworkers place the material on a piece of equipment known as a lathe. The lathe rotates the metal so that it can be shaped or cut using hand tools or specialty bits. This type of process can be used to create a threaded screw or similar fastener.

During milling, workers use a piece of equipment known as a milling machine. This equipment uses metal bits to cut material out of the surface or face of an object. The tool or bit is fixed in place, and the machine guides the metal around these cutting tools. This type of machining process may be used to cut a logo into a steel plate, or to form special tools.

A lot of machining today is done through computer numeric control machines, programmed by CNC operators.
A lot of machining today is done through computer numeric control machines, programmed by CNC operators.

Grinding is the final category of machining techniques. This relatively simple process involves using a stone-grinding wheel to shape or polish metal. This technique may be used to sharpen a metal hand tool or to give metal building materials a satin finish.

Machining is just a single part of a larger manufacturing process. Metal manufacturing begins with design, then proceeds through manufacturing and production. Machining may be used to shape the metal and create the object, or may serve only as a method of finishing the metal to give it the desired appearance. After machining is complete, the object must be finished and assembled before it is ready for sale.

Discussion Comments


@alchemy- You may be able to find a small CNC mill for around $4000-$5000, but they are expensive (and heavy) pieces of equipment. One of these mills will usually only have three axis movement, and you may need to buy all of the computer hardware and software separately.

You may want to consider leasing a CNC mill. You will be able to lease a $30,000 CNC milling machine for a good price. You can lease a high quality mill, or other CNC machine, for a few hundred dollars a month. Depending on how much you make selling your crafts or services, you may want to consider this route. This is a much cheaper way to set up a machine shop than purchasing a CNC mill outright. Leasing also means that you have better customer service should you have a problem with your machine.


How involved is the process of building a hobby CNC machine shop? I have used most wood and metal working tools, and I would love to put together a small machine shop in the basement of my house. I cannot afford to purchase a $10,000+ CNC machine because I only do wood and metalwork as a part time hobby.

I do sell some of my work, but I only have the time to create on the weekends. A CNC mill and lathe would save me time on the bulk work of many of my projects. Are there kits for DIY CNC machines? Does anyone know of any tabletop CNC machines that are reasonably priced?


@aplenty- You could learn the basics of CNC machining by taking a couple courses form your local community college or technical trade school. You will probably have to spend a couple hundred dollars, but you can go as a non-degree seeking student.

I was interested in learning about machining so I took an introductory course in CNC machining and a course on how to run CNC software. Beyond that, I learned how to run a CNC mill and lathe through my job.

The training was enough to get me a job at a custom car shop, and I occasionally run the machines in house. I can also use the machining tools to make my own custom parts, things like grilles, mirror housings, and interior accessories. If you do a search for CNC training courses in your area, I am sure you will find something that suits your needs and abilities.


@aplenty- Computerized Numerical Control (CNC) precision machining is machining that takes the controls out of human hands and places them into software. Essentially, the design is drafted through CAD or some other program, and the machines act as printers, taking commands from the computer about how to move on its axes. In fact, a printer is a type of CNC machine.

You can use CNC on virtually any type of metal or woodworking tool, allowing a computer to control a lathe, drill press, mill, grinder, or router. You can even combine these tools together to create CNC cells, self-contained units that can perform complex fabrications.

I have a friend who built a CNC machine that he runs out of his garage. He makes all kinds of things in his hobby machine shop. Things like signs, small robots, and custom speaker enclosures. I have seen him produce some really cool things, but he has been machining for at least 10 years.


What is CNC machining? I would like to learn how to work with metals. I would like to make things like belt buckles and plaques to start, but eventually creating more artistic pieces. Can I take classes in CNC machining without going back to college for a degree? How expensive is machining equipment? Are CNC machines only used for metalworking, or can they be used for things like fiberglass and wood too?

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    • Machining creates objects out of metal.
      By: Monkey Business
      Machining creates objects out of metal.
    • A lot of machining today is done through computer numeric control machines, programmed by CNC operators.
      By: uwimages
      A lot of machining today is done through computer numeric control machines, programmed by CNC operators.