A multi-axis lathe is a CNC lathe that controls more motions than the basic two, X and Z. The extra axes come from a C axis that positions the spindle, a Y axis that moves a live tool off center, a B axis that tilts a milling head, and from second spindles and second turrets that each bring their own axes. This guide explains how lathe axes are named, walks through the common configurations from a 2-axis lathe to a mill-turn machine, explains why axis counts are hard to compare, and shows how to tell what your own lathe has.
Machine Tool Exchange buys used CNC lathes and mill-turn machines directly from the shops that own them, so the guide ends with the details an owner needs on hand.
What Is a Multi-Axis Lathe?
A multi-axis lathe is any CNC lathe with axes beyond X and Z, which lets it drill, mill and finish features that a 2-axis lathe cannot reach in the same setup. A basic CNC lathe has two axes: Z along the spindle, which sets lengths, and X across it, which sets the diameter. Everything else on this page is added on top of those two.
If you are new to turning, start with our guide to what a lathe is and how its axes work. For the full range of machines, see our page for used lathes of every kind.
How Are Lathe Axes Named?
Lathe axes follow the international standard for machine tool axes, ISO 841. It sets up a right-hand coordinate system with three straight-line axes, X, Y and Z, and "rotary axes about each of these axes labelled A, B and C, respectively." On a lathe the spindle turns the workpiece, and the standard ties the axes to that spindle:
| Axis | What it is under ISO 841 | What it does on a lathe |
|---|---|---|
| Z | "Parallel to the principal spindle" | Moves the tool along the part's length |
| X | "Radial and parallel to the cross slide" on machines that turn the workpiece | Moves the tool toward or away from the center, setting the diameter |
| Y | Completes the right-hand set with X and Z | Moves a live tool above or below center, for off-center features |
| C | Rotation about Z | Positions or turns the spindle by angle |
| B | Rotation about Y | Tilts a milling head on a mill-turn machine |
The standard also covers machines with more than one of something. Where there are several spindles, it says "one shall be selected as the principal spindle." Secondary straight-line motions parallel to X, Y and Z "shall be designated U, V and W respectively," tertiary ones P, Q and R, and machines with several units may use a letter and a number, "X1, X2." So the program for a lathe with two turrets can refer to X1 and X2, but controls do not always follow the standard's lettering, so check your machine's manual. For lathes, the standard even treats the tailstock as the tool holder when it sets the Z direction.
The Common Configurations, Step by Step
Shops and builders often describe a lathe by its axis count: a "2-axis lathe," a "3-axis lathe," a "5-axis lathe." Those labels are common usage, not part of the standard, so it helps to know what usually sits behind each step:
- 2-axis lathe: X and Z only. It turns, faces, bores, grooves and threads.
- C axis and live tooling: powered tools in the turret, plus a C axis that holds or turns the spindle by angle. It can drill cross holes and mill flats without moving the part to a mill. This is often called a 3-axis lathe.
- Y axis: the turret also moves above and below center. Haas describes its Y-axis lathes as combining "generous Y-axis travel, full C-axis motion, and high-performance live tooling," for secondary operations "such as off-center milling, drilling, and tapping."
- Sub-spindle: a second spindle takes the part so the back side can be finished in the same cycle.
- Twin turret: a second turret works on the part at the same time as the first.
- Mill-turn: a full milling spindle on a B axis, often with a second spindle and a lower turret.
Builders often sell the machines at steps 2 to 5 as turning centers, as with the Haas ST series and the Doosan PUMA and Lynx lines. See our page for used CNC turning centers.
Sub-Spindles and Twin Turrets
A sub-spindle is a second spindle facing the main one. Haas puts the case for its DS dual-spindle lathes this way: "Dual-spindle turning combined with Y axis, C axis, and live tooling allows multiple operations in a single setup to reduce part handling and increase accuracy." The sub-spindle on those machines has its own "fully interpolated" C axis with a brake, so its rotation is a controlled axis in its own right. If the sub-spindle moves toward the main spindle to take the part, that travel is one more axis the control drives.
A second turret adds another X and Z pair. DN Solutions calls the PUMA TT a "Twin-spindle Twin-turret with Y-axis Turning Center," though its table lists no Y-axis travel for the MS models. The PUMA TW has "twin parallel spindles and twin turrets," with live tooling on its M models. Two turrets let two tools cut at once, and DN says the PUMA TT is built "for the fast and mass production" of precision parts. Our guide to the Haas lathe lines shows how one builder marks Y-axis and dual-spindle models in its model names, and our guide to Doosan's PUMA and Lynx lines does the same for another.
Mill-Turn Machines and the B Axis
A mill-turn (multi-tasking) machine is a lathe with a true milling spindle in place of, or in addition to, a turret. The milling spindle tilts on a B axis, so it can drill and mill at an angle as well as along and across the part. Mazak calls its INTEGREX machines "Multi-Tasking Machines" and offers the INTEGREX i-500 with a second spindle, a lower turret and a choice of milling spindles, including a No. 50 taper. DMG MORI calls its NTX an "Integrated Mill Turn Center." DN Solutions' fullest SMX models combine "the left and right spindles, the B-axis milling function and a lower turret."
Indexed or fine-positioned B axis. How finely the B axis positions differs from machine to machine, and it is worth knowing which one you have:
- On Mazak's entry-level INTEGREX j, the milling spindle "can be indexed in 5-degree increments from -30° to 190°," with 1-degree indexing as an option.
- On the INTEGREX i-500, the B axis positions in increments as small as 0.0001°.
Both tilt the milling spindle, but they are not the same capability. See our page for mill-turn and multi-tasking machines, which covers machines from Mazak, DMG MORI, Okuma and Doosan.
Why Axis Counts Are Hard to Compare
An axis count is the number of motions the control drives, not a measure of what the machine can cut. DN Solutions says its SMX series has "a total of nine axes." DN does not list them, but on its fullest SMX models two spindles, a B-axis milling head and a lower turret each bring axes of their own. Another machine can reach a similar count with a second turret and a sub-spindle and no milling head at all.
So two lathes with the same number can be built very differently, and a higher number is not always more useful for your parts. Compare the configuration instead: which spindles, which turrets, whether there is a Y axis, and whether the B axis is indexed or fine-positioned.
Multi-Axis Lathe vs. 5-Axis Machining Center
The difference is which part spins. On a multi-axis lathe the workpiece spins for turning, and the extra axes bring milling to the lathe. On a 5-axis machining center the tool spins, and two rotary axes are added to a mill's X, Y and Z so the tool can reach five sides of a part. They overlap at the top end, but they start from different machines. See our page for used 5-axis machining centers.
Swiss-type lathes, with their sliding headstock, are another multi-axis family with their own layout. See our page for Swiss-type turning machines.
How to Tell Which Axes Your Lathe Has
You can usually work out a lathe's configuration from the machine itself:
- The model name. Many builders put the configuration in the name: on Haas lathes, Y marks a Y axis and DS a dual-spindle model; on Doosan lathes, M marks milling, Y a Y axis and S a sub-spindle. The letters are not the same from one builder to the next.
- The turret. Driven tool holders mean live tooling. A second turret below or beside the first means a twin-turret machine.
- A second spindle facing the main spindle means a sub-spindle.
- A milling head with a tool changer instead of, or as well as, a turret means a mill-turn with a B axis.
- The control. The position screen usually lists each axis by its letter, which is the quickest check of all.
What to Note on a Multi-Axis Lathe You Own
To describe a multi-axis lathe accurately, collect these details:
- Model and serial number, from the data plate.
- Control maker, model and software version.
- Spindle hours, for the main spindle, the sub-spindle and the milling spindle where the control shows them.
- Configuration: chuck sizes, bar capacity, Y-axis travel, sub-spindle, number of turrets, live tooling, and on a mill-turn the milling spindle taper and tool magazine size.
- Attachments: bar feeder, parts catcher, tool presetter and any holders and tooling that go with it.
These are the same details we look at when we buy a used mill-turn or multi-tasking lathe. Machine Tool Exchange buys used CNC lathes, turning centers and mill-turn machines, running or idle. We buy outright and arrange the pickup. Request a quote or call 517-514-5190.
Frequently Asked Questions
What is a multi-axis lathe?
A multi-axis lathe is a CNC lathe with axes beyond the basic X and Z, such as a C axis, a Y axis, a B-axis milling head, a sub-spindle or a second turret. The extra axes let it drill and mill a part in the same setup it is turned in.
What are the axes on a lathe?
Z runs along the spindle and X runs across it, setting the diameter. On multi-axis lathes, C is rotation about Z (the spindle's angle), Y moves a live tool above or below center, and B is rotation about Y, which tilts a milling head. These names follow the ISO 841 standard.
What is the difference between a C axis and a Y axis on a lathe?
The C axis turns or holds the spindle at an angle, so a live tool can drill a cross hole or mill a flat at a set position. The Y axis moves the tool off the part's centerline, so it can mill and drill features that are offset from center.
What does a B axis do on a lathe?
On a mill-turn machine, the B axis tilts the milling spindle, so it can drill and mill at an angle. On some machines the milling head indexes in steps, such as 5 degrees; on others it positions in increments as small as 0.0001 degrees.
Is a mill-turn machine the same as a multi-axis lathe?
A mill-turn machine is one kind of multi-axis lathe: the kind with a full milling spindle on a B axis. A lathe with live tooling, a Y axis or a sub-spindle is also multi-axis, but it is not a mill-turn unless it has that milling spindle.
Have a multi-axis lathe or mill-turn machine you no longer need? Machine Tool Exchange is a direct buyer, so the offer comes from the buyer. We buy outright and arrange the pickup. Get a quote or call 517-514-5190.