Static & Driven Tool Holders For DMG Mori

A static tool holder carries a stationary cutting tool (a turning tool, a boring bar, a parting blade) that does the cutting while the spindle rotates the work. These are the holders for the conventional turning operations the lathe was built for.

A driven (live) tool holder carries a rotating tool (an end mill, a drill, a tap) that is powered by the turret drive, allowing milling, drilling, reaming and tapping to be performed on the lathe while the workpiece is held stationary in the spindle.

The driven holder is what turns a lathe into a turn-mill because it brings the secondary machining operations onto the turret, so a part can be turned, then drilled and milled without leaving the machine.

DMG MORI models with the "Y" and "SY" suffix (NL 300 Y, TS 3000 Y, L 250 SY, SKT 250 SY) carry the Y-axis capability that lets driven tools reach off-centre, which is how slots, flats and bolt-hole patterns are machined on the lathe.

VDI (Verein Deutscher Ingenieure / DIN 69880) is the industry-standard disc-type turret interface used on a generation of CNC lathes.

The tool holder has a cylindrical VDI shank that locates in a matching bore in the turret disc and is clamped by a radial serrated coupling; an axial drive key transmits the rotation to driven holders.

VDI 30 & VDI 40 are the two common shank sizes with VDI 40 the larger, suited to mid-size lathes, VDI 30 the smaller for compact machines.

On older DMG MORI / Gildemeister / Graziano machines (the CTX 400 and 500, the Graziano GR 400 C, the L 210/250 SY, the SKT 250) the turret is a 12-station VDI 40 disc, listed here as "Disk-Type 12ST DIN 5482 − VDI 40".

A VDI tool holder for one of these machines must be the VDI 40 shank size and carry the correct drive-key orientation, so the holder is matched to the turret rather than chosen generically.

The Star-Type turret is DMG MORI’s newer turret design fitted across the modern generation of lathes (the NL, NLX, NT, NTX, NZ, NZX, TS, ALX and DURATURN families).

The designation "12ST" (12-station), "10ST" and "16ST" refers to the number of tool stations on the turret and "D40" or "D60" the size of the holder interface that mounts on it. Holders for a Star-Type turret are not interchangeable with VDI disc holders because the mounting and drive are different.

So the rifle-selection questions on this category are the machine family (NLX, NTX, TS, etc.), the number of stations (10, 12, 16 or 20) and the interface size (D40 or D60, or VDI 30 / VDI 40 for the disc-type machines).

The filters in our category carry those exact combinations, for example NLX 2500 "Star-Type 12ST - D60", NTX 1000 "Star-Type 10ST - D40", CTX 400 "Disk-Type 12ST - VDI 40", so picking your machine model lands you on the holders that fit.

The model designation is on the machine nameplate and in the documentation; an "NLX 2500", an "NTX 2000", an "NT 5000" and so on.

The turret designation matters equally because a single machine model can be supplied with more than one turret: the NLX 2500 was offered in both a 10-station D60 turret and a 12-station D60 turret and the NLX 2500 in a 16-station and a 20-station D40 turret. The two turrets take different holders, so the turret must be identified, not just the model.

On the machine itself, count the tool stations on the turret and check the drive coupling (the Star-Type coupling is visibly different from the VDI disc’s keyed shank) and the interface size is cast or labelled on the turret.

If you have the machine manual, the turret specification is in the technical data. If you are unsure, tell us the model and the number of tool stations visible on the turret and we will confirm the correct interface.

The range we stock here covers the principal DMG MORI turning families;

• The NL and NLX are the compact-to-mid turning centres

• The NT and NTX are the turn-mill centres with the larger Y-axis and driven-tool capability

• The NZ and NZX are the production lathes

• The TS is the Y/YS turn-mill with the 3-keys turret

• The ALX is the entry compact

• The DURATURN is the legacy economy lathe

• The CTX, Graziano GR, L & SKT are the older disc-turret machines with VDI 40

• The ZT & MT filter covers the smaller Star-Type 16ST VDI 30 turret machines.

Each family has its own turret interface and within a family the interface can vary by size and station count, so the filter tree on this category is structured by machine model and turret.

The safest way to land on the right holder is to start from your exact model name and turret.

The Y & SY suffixes denote a Y-axis on the turret; an off-centre linear axis that lets a driven tool move across the spindle centre line, which is what allows milling of flats, slots and bolt-hole patterns and off-centre drilling on the lathe.

The NL 300 Y and SY, the TS 3000/4000/5000 Y and YS, the L 250 Y and SY, and the SKT 250 Y and SY all carry this capability.

For tool selection, the Y and SY machines take the same turret interface as their Y-less counterparts but are often fitted with the wider tooling envelope to accept the driven milling heads and Y-axis boring blocks the capability implies.

The Y designation does not usually change the holder shank but it changes which driven tools make sense on the machine; a Y-axis milling head, a thread-milling Live-Tool and an axial drilling head all earn their place on a Y/SY machine.

The static side of the turret carries the conventional lathe tooling.

• A square-shank turning-tool block holds the indexable turning and facing insert tool holders

• A boring-bar holder holds a cylindrical boring bar for internal turning

• A parting-block holder takes a parting blade for parting-off and grooving.

Each is a static block that mounts in the turret station and sets the tool on centre height, indexed repeatably when the turret stations.

On a VDI turret the static block mounts on a VDI shank with the correct orientation of the drive key (or a blank key for static use); on a Star-Type turret it mounts directly to the interface.

The block must set the tool tip to the correct centre height for the spindle (the machine’s centre height is a fixed figure, and the holder sets the tool to it) so the block is matched to the machine and the insert holder size.

The driven holders on DMG MORI lathes overwhelmingly use ER collets (ER16 on the smaller machines, ER20 and ER25 on the mid-range, ER32 on the larger) which clamp a cylindrical tool shank by a nut compressing the slitted collet.

ER collets cover a range of shank diameters around their nominal size, so a set of collets handles a spread of end-mill and drill shanks and runout is low enough for general milling and drilling.

For precision and high-speed milling, a shrink-fit holder takes a solid-carbide tool with an exact shank diameter, heated and cooled to lock the tool with the lowest runout and best balance.

Weldon-side-lock holders suit larger end mills with a flat (the set-screw bears on the flat to prevent axial slip under heavy milling).

Pick the collet type to the tool and the duty: ER for general use, shrink-fit for speed and precision, Weldon for heavy milling.

Most DMG MORI-driven and static holders in this category are available with through-tool coolant (the coolant is delivered through the holder and the tool, rather than only externally).

For a driven drilling or milling tool, through-coolant flushes the chips from the hole and cools the cutting edge directly, which is essential for deep drilling and high-speed milling and extends tool life considerably.

For a static boring bar, through-coolant reaches the cutting edge in the bore where external coolant struggles.

Through-coolant requires the holder to have the internal ducting and the correct interface to the machine’s coolant supply and the tool itself must be a coolant-through tool.

If your machine has through-coolant at the turret (and most modern DMG MORI lathes do), choose the through-coolant holder variant where the tool benefits (deep drilling and milling in particular).

The gain in tool life and chip control is well worth the small additional cost.

Centre height (the distance from the spindle centre line to the cutting tip) must be exact for accurate turning and a good finish and the static block on a DMG MORI turret is designed to set it.

The block mounts the turning-tool holder at the machine’s centre height with the adjustment for tip height on the holder itself or by shim beneath the tool. Set the tip to centre using a height gauge or by touching the tool to a bar held between centres and lock the tool.

On the VDI disc the holder orientation is fixed by the shank and the drive key, so a holder that is the correct part for the machine sets the tool close to centre by design; final set is by tip adjustment.

On the Star-Type turret the block indexes to the station and sets centre height by its design.

A tool off centre (high or low) turns a tapered or poor-finish part, so taking the time to set centre once per tool pays back on every part that follows.

Keep the turret interface clean and correctly torqued.

The accuracy of a turret system depends on the holder seating cleanly on the turret (swarf and coolant residue between the mating faces is the most common cause of a holder not indexing true, which shows up as a poor or inconsistent part. Wipe the turret face and the holder shank before fitting, and torque the clamping bolt to the machine maker’s figure) under-torqued holders shift under cut, over-torqued ones distort the interface.

On driven holders, the collet and nut are the moving parts (keep the collet clean and free of swarf, inspect the nut and the drive key for wear, and replace a collet that has begun to mark the tool shanks or allow runout).

The turret drive coupling itself should be inspected at the service intervals the machine manual specifies (a worn coupling causes driven-tool runout and poor milling finish).

Store spare holders clean and in a rack with the tooling left in place, so a holder returns to use ready-set.

Generally not, the turret interface is matched to a specific machine model and turret.

A VDI 40 holder for a CTX 500 will not mount on a Star-Type NLX 2500 and a D60 holder for an NLX 2500 will not fit the smaller D40 interface of an NL 200.

Even within a single family, different turret variants (10ST vs 12ST, 16ST vs 20ST, D40 vs D60) take different holders and mixing them is the most common ordering mistake.

There are a few genuine cross-model and cross-make fits where the interface is shared; some VDI 40 holders, for instance, fit machines across the CTX, Graziano and L/SKT families that share the DIN 69880 interface but the safe rule is to order by your exact machine model and turret.

If you hold both a CTX and an NLX and want to know whether a holder carries across, tell us the two machines and we will confirm before you order.

Begin with the static turning set.

A square-shank turning-tool block for your main OD turning and facing, a boring-bar holder for the internal work and a parting-block holder for parting-off.

From there, add a second turning block for a finishing tool so the two operations have their own permanent stations. That is the baseline that lets the lathe do what it was bought for.

For a turn-mill, add an axial driven drilling/milling head with an ER-collet set to cover the centre-line drilling and end-milling, and a radial milling head for the cross-work, that pair unlocks the milling capability the machine carries. Thread-milling, tapping and angle heads come as the work demands.

Tell us your model, turret and the parts you intend to make and our in-house, time-served engineers will put together a matched tooling list that fits the turret and covers the work from the first set-up.