Lathes are machine tools that spin a workpiece while a cutting tool shapes it. They make the round parts in almost everything that moves: shafts, pins, bushings, fittings, rollers. This guide explains how a lathe works, names its main parts and axes, and walks through the types, from a manual engine lathe to a CNC turning center with live tooling and a second spindle.
Machine Tool Exchange buys used CNC lathes and turning centers directly from the shops that run them, so the guide ends with the specs that describe any lathe, the same details an owner needs when the time comes to sell one.
What Is a Lathe?
A lathe is a machine tool that rotates a workpiece about an axis while a cutting tool removes material from it. Because the part spins against the tool, a lathe produces shapes that are round around that axis: cylinders, cones, shoulders, grooves and threads. It is one of the oldest machine tools; the earliest known depiction of one is in the tomb of Petosiris in Egypt, from the 4th century BC.
Modern metalworking lathes grew out of the screw-cutting lathes of the Industrial Revolution. From the 1950s, servo motors under numerical control began replacing the hand wheels, and numerical control coupled with computers became CNC. Today a CNC lathe runs from a program, usually G-code, and CNC lathes have replaced many older production lathes because they are easier to set up and repeat the same part accurately.
Lathes turn metal, plastic and wood. This guide covers metalworking lathes, the kind found in machine shops and production plants.
How Does a Lathe Work?
A lathe works by clamping the workpiece in a spindle that spins it, then feeding a cutting tool into the spinning part along two directions: along its length to set a length or shoulder, and toward its center to set the diameter. Each pass removes a thin layer until the part reaches its final shape.
The difference from a mill is stated in one line: on a lathe the workpiece spins and the cutting tool does not; on a mill the cutting tool spins and the workpiece does not. That is why lathes make round parts and mills make flat faces, pockets and holes. Turning centers with live tooling blur the line by adding spinning tools to the lathe. For how turning fits alongside milling, drilling and grinding, see our overview of the main types of CNC machines.
On a manual lathe the machinist moves the tool with hand wheels. On a CNC lathe, servo motors move it along programmed paths, and a turret holds a set of tools that index into position on command.
What Are the Main Parts of a Lathe?
The main parts of a lathe are the bed, the headstock, the spindle, the chuck, the tailstock and the carriage with its cross-slide. On a CNC lathe, a tool turret takes the place of the manual tool post, and a control runs the machine.
- Bed: the heavy base, flat on a manual lathe and often slanted on a CNC lathe, that carries everything else and keeps it aligned.
- Headstock: the housing at one end with the high-precision bearings and the drive for the spindle.
- Spindle: the rotating shaft in the headstock that spins the work.
- Chuck or collet: the workholding on the spindle nose. A three-jaw chuck self-centers round stock; a four-jaw chuck adjusts each jaw for odd shapes; a collet grips bar stock.
- Tailstock: slides along the bed to support the far end of long work or to hold a drill.
- Carriage and cross-slide: the carriage travels along the bed and the cross-slide moves across it, carrying the tool.
- Turret (CNC): an indexing tool holder with a set of tool stations.
- Control (CNC): the computer that reads the program and drives the axes.
What Do the Axes on a CNC Lathe Mean?
A basic CNC lathe has two axes. The Z axis runs parallel to the spindle and sets lengths and shoulders; the X axis runs at right angles to the spindle and sets the diameter. Many turning centers add a C axis, which indexes the spindle to a set angle, and some add a Y axis, which moves the tool off the centerline.
In practice:
- Z axis: tool movement along the part's length, toward or away from the headstock.
- X axis: tool movement toward or away from the part's center. Most lathes program X as a diameter, so on a lathe set up in inches a move to X2.0 cuts a 2-inch diameter.
- C axis: control of the spindle's angle, so the part can stop at a set position for a cross hole or a flat.
- Y axis: a third straight-line axis that lets a live tool cut features offset from the center, such as slots and off-center holes.
With live tooling plus C and Y axes, a lathe can turn, drill and mill a part in one setup.
What Are the Main Types of Lathes?
The main types of metalworking lathes are the engine lathe, the toolroom lathe, the turret lathe, the CNC lathe, the CNC turning center, the Swiss-type lathe, the vertical turret lathe and the multispindle lathe. They differ in how the tools are held, how the work is supported, and how much of the cycle the machine runs on its own.
| Type | How it differs | Typical use |
|---|---|---|
| Engine lathe | Manual lathe with automatic feed to the cutting tool | Repair work, one-offs, toolroom jobs |
| Toolroom lathe | A top-of-the-line engine lathe with the best options | Precision one-offs and tooling |
| Turret lathe | An indexing tool holder for repeat operations | Repetitive production of duplicate parts |
| CNC lathe (2-axis) | Program-driven X and Z axes with a tool turret | Shafts, bushings, fittings in any quantity |
| CNC turning center | Enclosed production CNC lathe; many add live tooling, a C axis, a sub-spindle or a Y axis | Parts that need turning plus drilling and milling |
| Swiss-type lathe | Sliding headstock; the bar runs through a guide bushing next to the tool | Long, slender, small-diameter precision parts |
| Vertical turret lathe (VTL) | The spindle is a horizontal table; tools come down from above | Large-diameter, heavy parts such as rings and discs |
| Multispindle lathe | Several spindles working at once | High-volume production |
A few notes on the less familiar ones. The Swiss-type lathe came out of 19th-century Swiss watchmaking: supporting the bar in a guide bushing right beside the tool keeps small, slender parts accurate. More on sliding-headstock Swiss machines. A vertical turret lathe is a lathe stood on end, so gravity holds heavy parts on the table; more on VTLs and vertical lathes. Most production lathes today are CNC; see our page on used CNC lathes.
What Is the Difference Between a CNC Lathe and a Turning Center?
The terms overlap. A CNC lathe is the broad term and can mean a simple 2-axis machine whose turret tools only turn. A turning center is an enclosed production CNC lathe, and many carry live (powered) tools and C-axis spindle control so they can also drill and mill; some add a sub-spindle, a Y axis, or both.
The clearest way to place a machine is by capability. Think of it as a ladder:
- 2-axis CNC lathe: X and Z only; turning, facing, boring, grooving, threading.
- Live tooling and C axis: powered tools in the turret, spindle indexing; cross holes, flats and simple milling.
- Sub-spindle: a second spindle catches the part at cutoff so the back side is finished in the same cycle.
- Y axis: off-center milling and drilling.
- Mill-turn (multi-tasking): a full milling spindle, often on a tilting B axis, plus the turning spindle; see mill-turn machines.
Each rung means fewer separate machines and setups for the same part. Our page on production turning centers covers the machines on rungs 2 to 4.
If you own a lathe or turning center you no longer need, Machine Tool Exchange buys them directly. Request a quote or call 800-822-9524.
What Can a Lathe Make?
A lathe makes any part that is round around an axis, and with live tooling, round parts with milled features. Common lathe operations are turning (reducing a diameter), facing (squaring the end), boring (enlarging a hole), drilling on center, grooving, threading, knurling and parting off.
Typical lathe parts include:
- Shafts, axles and pins
- Bushings, sleeves and spacers
- Threaded fittings and connectors
- Pulleys, rollers and flanges
- Valve bodies and hydraulic components
Which Specs Describe a Lathe?
Every lathe is described by a handful of specs: swing (the largest diameter that clears the bed; CNC spec sheets also list a smaller maximum cutting diameter), distance between centers or maximum turning length, bar capacity (the largest bar that passes through the spindle), chuck size, spindle speed and power, the number of turret stations, and the control. Options such as live tooling, a sub-spindle, a Y axis and a bar feeder complete the picture.
These specs set what work a lathe can take on, and a buyer or appraiser will want them. If you are recording them, the nameplate gives the builder, model, serial number and year; the control screen shows the control make and software; the manual or the builder's spec sheet gives swing, length and bar capacity. For how those details play into what a used lathe is worth, see our CNC lathe resale value guide.
Frequently Asked Questions
What is a lathe used for?
A lathe is used to make round parts by spinning the workpiece against a cutting tool. It turns diameters, faces ends, bores and drills holes on center, cuts grooves and threads, and parts finished pieces off the bar. Shafts, pins, bushings and threaded fittings are typical lathe work.
What is the difference between a lathe and a mill?
On a lathe the workpiece spins and the cutting tool does not, so it makes round parts. On a mill the tool spins and the workpiece is clamped in place, so it makes flat faces, pockets, slots and holes. A turning center with live tooling does some of both.
What does CNC stand for on a lathe?
CNC stands for computer numerical control. A CNC lathe's axes are driven by servo motors following a program, usually written in G-code, instead of by hand wheels. That lets it repeat the same part accurately and run with little operator input.
What is a Swiss-type lathe?
A Swiss-type lathe feeds bar stock through a guide bushing that supports it right next to the cutting tool, while the headstock slides to move the bar. It was developed for Swiss watch parts and is used for long, slender, precise parts.
What is an engine lathe?
An engine lathe is a traditional manual metalworking lathe with automatic feed to the cutting tool. It is the general-purpose lathe of toolrooms and repair shops, run by a machinist rather than a program.
Have a CNC lathe, turning center or Swiss-type lathe you want to sell? Machine Tool Exchange buys used lathes directly, so the offer comes from the buyer. Get a quote or call 800-822-9524.