A vertical turret lathe, or VTL, is a lathe stood on end. On the large conventional design, the workpiece sits on a horizontal table that rotates about a vertical axis, and the tool head is carried above the table. That layout suits large, heavy, short workpieces such as train wheels, gear blanks and engine casings, and it also turns smaller heavy parts such as wheel hubs and brake drums. This guide explains how a VTL works, names its main parts, compares it with a vertical boring mill and a horizontal lathe, and lists the specs that describe one.
Machine Tool Exchange buys used vertical turret lathes and vertical boring mills directly from the shops that own them, so the guide ends with the details an owner needs on hand when the time comes to sell one.
What Is a Vertical Turret Lathe?
A vertical turret lathe is a lathe whose axis of rotation is vertical and whose tools are held in a turret. On the conventional large design, the workpiece is clamped to a horizontal rotating table, which lets the headstock sit on the floor and turns the faceplate into that table. This arrangement is made for very large, heavy, short workpieces.
Vertical lathes in general are also called vertical boring mills, or often simply boring mills, and a vertical turret lathe is a vertical boring mill equipped with a turret. Vertical lathes range widely in size, with swing diameters from under 1 meter (about 3 feet) to over 20 meters (more than 65 feet).
Manual vertical lathes exist, but CNC vertical turning machines are more popular than manual ones, because operator access is less of an issue on them. If you are new to lathes in general, start with our guide to what a lathe is and how it works.
How Does a Vertical Turret Lathe Work?
A conventional VTL works by clamping the workpiece to a rotating table and feeding a cutting tool into the part as it turns. The table spins the part about a vertical axis, and the tool head moves along a vertical axis (Z) and a horizontal axis (X) to position each cut along the part's height and across its diameter.
In turning, it is the workpiece that rotates while the cutting tool is fed into it. A turret holds several tools on an indexing tool holder, so one cut can follow another with a different tool in rapid succession.
Loading is the part that changes. Instead of chucking a large part horizontally, the operator sets it down on the table and clamps it. The rotating plate is often a cast iron faceplate with T-slots for the clamps.
What Are the Main Parts of a VTL?
The main parts of a conventional VTL are the bed and base, the rotary table, the column and cross rail, the turret head, the spindle and drive, and the control. Each does one job.
- Bed and base: the foundation that carries the machine.
- Rotary table: on the conventional design, the horizontal table, often a faceplate with T-slots, that holds and turns the workpiece.
- Spindle and drive: the main drive that rotates the table.
- Column and cross rail: the vertical column and the horizontal cross rail that support and move the tool head. On some machines the turret head is mounted on a column that moves left and right in X, which lets the machine handle larger-diameter and taller parts.
- Turret head: the indexing tool holder that carries several cutting tools.
- Control (CNC): the computer that reads the program and drives the axes.
What Is the Difference Between a VTL and a Vertical Boring Mill?
The two names overlap. Vertical lathes are commonly called vertical boring mills, and a vertical turret lathe is a vertical boring mill with a turret added. A machine may be described either way, so check the nameplate and the machine itself rather than relying on the name.
Neither should be confused with a horizontal boring mill, which is a different machine with a horizontal spindle. A horizontal boring mill can be the better choice for some very large parts, particularly ones that need long or deep bores. Machine Tool Exchange buys both kinds; see our pages on vertical boring mills and horizontal boring mills.
Why Turn a Part Vertically?
Turning vertically makes large, heavy parts easier to hold, load and cut. The main reasons:
- Gravity helps. The part's weight helps anchor it on the rotating table, and gravity helps hold fragile workpieces in place.
- Loading is easier. A large part can be set on the table and clamped, instead of being chucked horizontally.
- Chips fall away. Gravity helps chips drop away from the part instead of accumulating around it.
- A compact envelope. A vertical lathe can turn relatively large parts in a comparatively compact machine.
- More than turning. Other operations, including drilling, milling, reaming and threading, can be done in the same setup.
The trade-off is operator access: standing a lathe on end is less convenient for the operator, but it makes large parts easier to support. On some of the largest machines the turntable is installed flush with the floor to make loading easier.
How Does a VTL Compare With a Horizontal Lathe?
A horizontal lathe holds the work on a horizontal axis, in a chuck or between centers. A conventional VTL holds it on a table and suits parts that are large in diameter and short in length.
| Horizontal lathe | Vertical turret lathe | |
|---|---|---|
| Axis of rotation | Horizontal | Vertical |
| How the part is held | In a chuck or between centers | On the conventional design, clamped to a horizontal rotating table |
| Typical work | Long, slim parts such as shafts, and other parts turned on a horizontal axis | Very large, heavy, short workpieces |
| Loading a large part | Chucked horizontally or set between centers | Set down on the table and clamped |
For a broader look at where turning sits among all machine families, see our guide to the main families of CNC machines.
What Is Made on a VTL?
VTLs turn large, heavy parts for energy and heavy industry, as well as marine, railroad, construction and agricultural equipment. Typical VTL work includes:
- Wheel hubs, brake drums and train wheels
- Gear blanks and gears
- Turbine rotors and engine casings
- Large components for wind turbines and other energy equipment
Can a VTL Drill and Mill?
Some can. Drilling, milling, reaming and threading can be done in the same setup on a vertical lathe, and VTLs built for gear work can combine turning, drilling, milling, tapping and hobbing. A machine that adds full milling capability is closer to a mill-turn machine; see our page on mill-turn and turn-mill machines.
Single-Column or Double-Column?
Smaller vertical lathes generally have a single column, and larger ones typically have two. The column configuration is one of the first things worth noting when you describe a VTL, because a single-column and a double-column machine of similar table size are different conversations.
Which Specs Describe a VTL?
A VTL is described by a short list of specs. Table diameter and maximum swing set the ceiling on what the machine can hold, so they are the first two numbers to have ready. After that come the column configuration, the control make and generation, and the condition of the machine in practical terms: whether it still holds tolerance, what shape the ways and ram are in, and whether it is running, sitting idle or already decommissioned.
If you own a VTL you no longer need, the data plate is the place to start. It gives the serial number, the model designation and the build year, and a photo of the plate is more reliable than memory. Because these machines are large, also note the overall length, width and height as it sits, plus any pit or foundation detail, since that shapes the removal plan.
Machine Tool Exchange buys used vertical turret lathes outright, in any brand and any condition. We buy outright and arrange the pickup. Request a quote or call 800-822-9524.
Frequently Asked Questions
What does VTL stand for?
VTL stands for vertical turret lathe. It is a lathe with a vertical axis of rotation and a turret that holds the cutting tools. On the usual large design, the workpiece is clamped to a horizontal rotating table.
What is a vertical turret lathe used for?
A vertical turret lathe is used to turn large, heavy, short workpieces that are easier to set down and clamp on a table than to chuck horizontally. Typical work includes train wheels, gear blanks, turbine rotors, engine casings, wheel hubs and brake drums.
Is a VTL the same as a vertical boring mill?
The names overlap. Vertical lathes are also called vertical boring mills, and a vertical turret lathe is a vertical boring mill equipped with a turret. A horizontal boring mill is a different machine.
What is the difference between a VTL and a horizontal lathe?
On a horizontal lathe the work is held on a horizontal axis, in a chuck or between centers. On a conventional VTL the work is clamped to a horizontal rotating table that turns about a vertical axis, so gravity helps hold heavy parts in place and loading is easier.
Does a VTL have to be CNC?
No. Manual vertical lathes exist, but CNC vertical turning machines are more popular than manual ones. Machine Tool Exchange buys both CNC and manual vertical turret lathes.
Have a vertical turret lathe or vertical boring mill you want to sell? 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 800-822-9524.