Metal Lathe Applications: A Guide to Machining Possibilities

Lathes are one of the most important machines in history and the modern workshop. They allow highly accurate cylindrical objects to be made, such as shafts, threads, bushings, pins,  spacers and more.

Having and knowing how to use a lathe can massively expand your workshop’s abilities. To find out more, this guide explains some of the key factors: how they work, what you can do with one, and what they are used for.

What is a metal lathe and how does it work?

A lathe is a simple device that spins a piece of material or part and uses fixed tooling to remove material with high levels of precision. A metal lathe will typically be more rigid, accurate, and have various powered “feeds” to move the tooling at consistent rates compared to a wood lathe.

In principle, a lathe is a simple machine, a powerful motor is used to rotate the spindle via a speed selection device (gearbox, belt system, etc.). In most operations, a standard 3 or 4 jaw chuck is mounted to the spindle and allows the workpiece to be held firmly.

The carriage, holding the cross slide and toolpost, is then moved, either by turning handwheels, operating powered feeds, or via servo motors in the case of a CNC lathe, to bring the tool in contact with the work.

Extremely hard tooling is used, such as high-speed steel or tungsten carbide, that “shaves” off material from the surface of the workpiece. Typically, material will be removed in thicknesses up to 2mm on small to medium sized lathes but much more on more powerful machines.

A typical metal lathe consists of the following, but is not limited to:

• The base or frame: a solid, often cast, that houses all the components and has a flat, machined bed
• A carriage: moves up and down the bed in the Z axis (along the spindle axis)
• Cross slide: mounted to the carriage, this moves the toolpost in the X axis (across the spindle axis) to do parting and facing operations among others
• Tailstock: a frame that slides on the bed, and is typically used to support long parts, or hold machine tools such as drills or taps concentrically to the main spindle axis

Key Metal Lathe Operations: Turning, Facing, and More

One of the biggest advantages of lathes is their versatility, they can perform many different operations with minimal tooling:

• Turning: removing material from the outside diameter of a part
• Facing: removing material from the end of a part
• Drilling: making a hole in the end of the part, concentric to the main axis
• Boring: extending, widening or adding details (such as a step or groove) to a hole in the end of a part
• Tapping: making female threads using a tap
• Thread cutting: cutting male threads using a cutting tool
• Parting: cutting a part in two using a parting off tool
• Knurling: adding a knurled finish to the outside of a part
• Chamfering: breaking a 90° corner with a 45° or similar angle

Materials You Can Machine with a Metal Lathe

Almost any solid material used in manufacturing can be turned on a lathe, as long as the material is a solid, and not flexible or malleable, such as rubber:

• Steels: Mild, stainless, tool, etc
• Cast iron
• Aluminum, copper, brass
• Plastics: nylon, acetal, delrin etc
• Wood

Metal Lathe Applications Across Industries: Real-World Examples

Lathes have innumerable uses across industry, and will have played a part in almost every part of the production process:

• Shafts and other rotating assemblies: manufacturing of anything from paper to vehicles, uses machinery to move, manipulate and process the work, including conveyor belts, track systems and robotic/CNC machinery. All of these use shafts, bearings, pulleys and couplers that will have been made on lathes.
• Hydraulics: earth moving equipment, presses, and even airplanes use hydraulic or pneumatic systems extensively. The precise fits needed between these cylinders and pistons require the accuracy and precision
• Pipe fittings and valves: oil & gas, HVAC, high pressure systems, all use valves, fittings such as quick release couplers, and flanges.

Choosing the Right Metal Lathe for Your Project: Factors to Consider

There are hundreds of different configurations of size, type and capacity of lathe, selecting the right one is important:

• Size: conventional lathes are measured by their “swing” – the maximum diameter of workpiece they can turn, and “distance between centres”, affected by the length of the bed
• Rigidity: harder materials need more rigidity in the frame of the machine to ensure accuracy. Certain lathe types are better equipped for harder materials, but this often comes with a cost
• Control: conventional manual lathes are still common but are being replaced by CNC machines that can make multiples of parts with fewer mistakes and more speed.

Metal Supermarkets for Machining Materials

Once you have your lathe, you’ll need a reliable, cost effective supply of machinable material. Metal Supermarkets holds a wide range of sizes, grades and shapes that are perfect for machining projects.

With home delivery and cutting services available too, it’s the perfect service to start making accurate, cost-effective parts on your lathe!