Meet the Machine

Used DMG MORI NLX 4000: The Letter After the Number Is the Spindle

Two used NLX 4000s can carry the same year, the same bed length and the same model number, and one of them can pass a bar 47 mm bigger than the other.

That is not a typo in one of the listings. Mori Seiki built the NLX 4000 with two different spindles. Type A carries a 15 inch chuck, a 145 mm spindle hole and 2,000 rpm. Type B carries an 18 inch chuck, a 185 mm spindle hole and 1,500 rpm. Same bed length, same turret, same control, same name on the door.

The only place the difference shows up is one letter in the full model string, right after the 4000. A listing that just says NLX 4000 has left out which spindle the machine has.

Here is how to read it, and what else the name does not tell you.

Type A or Type B: Read the Plate

Mori Seiki's own launch specification from November 2012 splits the two types like this.

Same motor, same bearing, same 750 bed designation. What you are choosing between is speed and bore.

Type A gives you 500 more rpm and a shorter footprint. Type B gives you 40 mm more spindle hole, 47 mm more bar and three more inches of chuck, and it costs you 25 mm of turning length on the 750 bed and 424 mm of floor, about 16.7 inches.

If your work is tube, pipe or large bar that has to pass through the spindle, the B is the machine and the A will not do the job no matter how good its condition is. If your work is chucked parts, or bar under 117 mm, the A is the more useful spindle, because the extra 500 rpm helps on smaller diameters and you are not paying floor space for a bore you will not use.

Reading the Rest of the Name

A full NLX 4000 model string from the launch era reads like NLX4000AY/750. Three things are packed into it after the model number: the spindle type, the axis configuration and the bed.

The axis configuration is either MC or Y. MC means the milling function, a C axis and rotary tools on the turret. Y adds a Y axis with plus or minus 60 mm of travel. The Y is not free.

Adding the Y costs 100 mm of turning diameter and 50 mm of X. If your largest part is between 500 and 600 mm across, the MC is the only one of the two that will turn it. We wrote about the same trade on the smaller machine in our NLX 2500 breakdown, where the turret options take a bite out of swing too.

The bed is the number after the slash. The launch table listed only the 750 bed, 750 mm between centers. DMG MORI's current page lists two: the 750 type with 875 mm of Z travel and a 746 mm maximum workpiece length, and the 1500 type with 1,685 mm of Z and a 1,584 mm maximum workpiece length. Later literature writes the name with a bar instead of a slash, NLX 4000 | 750, which is the same machine.

One more thing the number does not do. On the rest of the NLX family, the model number is the chuck size in inches times 250: an NLX 2500 is a 10 inch machine, an NLX 3000 a 12. Neither NLX 4000 fits. Fifteen times 250 is 3,750, and eighteen times 250 is 4,500. If you have been decoding NLX machines by that rule, it breaks here. There is more on how Mori Seiki named its lathes in our guide to reading a Mori Seiki NL model name.

Slideways on Every Axis

Mori Seiki's launch release is direct about the structure: slideways for all axes, chosen for rigidity and damping when cutting large workpieces, with slideway width increased by up to 50 percent. DMG MORI's current page puts it as slideway area 50 percent larger on X and 90 percent larger on Z than its conventional machine, with large diameter ball screws.

The bed is a 45 degree slant. Mori Seiki specified the distance from the spindle center to the door opening at 367 mm, about 14.4 inches, and called out that number for a reason. On a machine that turns parts up to 600 mm across, how far you have to reach into the enclosure to load a heavy part is a daily problem, not a spec sheet one.

Behind the chuck sits a spindle bearing with a 200 mm inner diameter, carrying 37 kW for 30 minutes and 30 kW continuous. That is the package Mori Seiki built the machine around: wide ways, a big bearing, and enough motor to use them.

The Coolant Inside the Castings

Mori Seiki's headline for the launch was offering the machining capability of a large lathe with the accuracy of a small one. The mechanism behind that claim is coolant.

The NLX 4000 circulates coolant inside its castings to keep the structure at a stable temperature, fed from a 708 liter tank, about 187 gallons, sized so the coolant temperature itself stays steady. Mori Seiki claimed thermal displacement of less than one third of its conventional machines. It also added periodic error compensation on the C axis, which it said halved C axis positioning error. DMG MORI's current page lists C axis positioning accuracy of 6.8 seconds.

There is a detail on the current page worth reading twice. DMG MORI lists the coolant circulation inside the castings for the 750 type. It does not list it for the 1500. If you are looking at a long bed machine and thermal stability matters to your work, ask what that specific machine has rather than assuming the feature came with the name.

Mori Seiki Rated the Turret Against a 40 Taper

The turret is Mori Seiki's BMT, Built-in Motor Turret, with the milling motor inside the turret rather than driving the tools through a gear train. By the NLX 4000 launch Mori Seiki said it had delivered more than 12,000 BMT units.

On the standard turret Mori Seiki claimed 10,000 rpm, up from 6,000 on its earlier turret, reached in 0.45 seconds, with turret vibration under one third and temperature rise under one tenth of a gear driven turret.

The option changes what the turret is for. Mori Seiki said the high torque milling specification lets the lathe cut as powerfully as a machining center with a No. 40 taper spindle, and that the turret can run M30 taps. The trade is speed: two and a half times the torque at four tenths of the top speed. A machine that runs big drills, big taps and heavy face milling wants the option. A machine that runs small end mills and cross drilled holes wants the standard turret and its 10,000 rpm.

The option is not visible from across the floor. Ask for the build sheet, or check the rotary tool maximum speed in the control. A 4,000 rpm limit tells you which turret you have.

The Numbers Underneath

Specifications vary by year and build, so pull the sheet for the exact serial number in front of you. These are the figures common to both spindle types, from the 2012 launch release and DMG MORI's current page.

One number is missing from what DMG MORI publishes openly: machine mass. The current page gates the full technical data behind an account login. If weight matters for rigging or your floor, get it from the seller in writing along with the serial number.

Which Control You Are Getting

The NLX 4000 launched on MAPPS IV, Mori Seiki's operating system for its lathes, with conversational programming, a customizable main screen and a 3D interference check that Mori Seiki said worked during C axis, Y axis and second spindle machining.

DMG MORI's current page lists one control option for the NLX 4000: MAPPS on Mitsubishi. The current version pairs MAPPS V with the CELOS interface on a 21.5 inch multitouch screen. That is a narrower story than the NLX 2500, which our breakdown traced across four control platforms under one model name.

On a used machine, confirm the control generation in writing along with the year and full model string, and ask what options are enabled rather than fitted. Interference checking, threading and hobbing cycles were options, not givens.

Where the 4000 Sits in the NLX Family

When Mori Seiki launched it in 2012, the NLX 4000 was the largest machine in the NLX series. It kept that position for almost seven years, until DMG MORI began taking orders for the NLX 6000 in July 2019, a machine with a 920 mm maximum turning diameter.

So the 4000 is the big NLX that most shops will actually meet. It sits above the NLX 2500 and NLX 3000, the 10 and 12 inch machines that make up most of the used NLX market, and below a 6000 built for a different class of part entirely. The company that built it has changed names since: Mori Seiki became DMG MORI SEIKI in October 2013 and DMG MORI after that, which is why the same machine turns up in listings under both names. More on the company in our DMG MORI brand profile.

U.S. Parts and Service

DMG MORI USA is headquartered in Hoffman Estates, Illinois, with service centers in Charlotte, North Carolina; Cypress, California; Tukwila, Washington; Houston, Texas; Wyoming, Michigan; Somerville, Massachusetts; Wheat Ridge, Colorado; and Medina, Ohio. For a machine this size that matters more than it does on a small lathe, because nobody ships an NLX 4000 somewhere to be repaired. Service comes to it.

The BMT turret is a good reason to want factory support nearby, because the milling motor lives inside the turret. Ask the seller for the service history and whether the turret has ever been rebuilt or replaced.

Used-Market Value

Five things move the number on a used NLX 4000.

Type A or Type B. Neither is worth more in the abstract. Each is worth more to the buyer whose work needs it, and a B with a 185 mm hole is a different purchase for a shop running tube than for one running chucked parts.

MC or Y. The Y adds capability and removes 100 mm of diameter. Price it against what you will actually cut.

The milling spec. Standard or high torque, and 10 or 12 stations.

Bed length. 750 or 1500, and on a 1500, what thermal control it has.

Scarcity. When we surveyed the used NLX market for our NLX 2500 piece, we found one or two NLX 4000s for sale in North America. You may not get to choose between an A and a B, which is exactly why you need to know which one your work needs before one comes up.

What to Check on a Used NLX 4000

Read the whole model string. Spindle type, MC or Y, bed length, serial number and year. If the listing does not include the letter after the 4000, ask for a photo of the plate.

Confirm the spindle against your work. Measure the through hole and confirm the chuck size and bar capacity. A Type A will not pass a bar a Type B will.

Inspect the slideways. Check the way wipers, look for scoring on any exposed way surface, and confirm lubrication is reaching the ways.

Test the thermal story. Warm the machine up, cut or measure a feature, and check it again after an hour of running. The coolant system is part of the accuracy on this machine, so check the tank, the pump and the condition of the coolant.

Run the turret. Index every station, run the live tools through their full speed range, and check for heat and noise at the top. Check the maximum rotary tool speed in the control to confirm standard or high torque.

Check C and Y. Index the C axis and run the Y through its full plus or minus 60 mm on a Y type, checking for backlash at reversal.

Watch a real part run. Ideally a heavy one, from the machine's own program. On a lathe built for large work, seeing it cut under load tells you more than any static check.

Resell CNC Take

Read the letter before you read the price. An A and a B share a model number and a motor, and then differ in exactly the places that decide whether the machine can run your work: 500 rpm, 3 inches of chuck and 47 mm of bar. Settle the spindle type first, then MC or Y, then the milling spec. Condition only matters once you know it is the right machine.

Who Runs One

Mori Seiki aimed the NLX 4000 at oil and gas work, construction and agricultural machinery, and hydraulic and pneumatic equipment. DMG MORI's application examples for it include pulleys, oil and gas couplings, axle shafts, flanges and ball screws.

That is a fair picture of the shop that buys one: large diameter parts, heavy stock removal, and enough milling on the part that doing it on the lathe saves a second setup. If your work runs to oil country components, our Meet the Machine on the Doosan Puma 800 covers another big-bore option.

It is usually not a first lathe. A shop tends to arrive at a machine this size after running out of chuck, bore or swing on something smaller, and it knows exactly which parts did it.

Frequently Asked Questions