Lathe Tool Holders

Lathe tool holders are the devices that mount cutting tools (turning tools, boring bars, drills, taps, reamers and driven milling cutters) to the turret or toolpost of a CNC lathe or turning centre.

The holder locates and clamps the cutting tool with the correct projection, orientation & rigidity and transmits the cutting forces into the machine structure.

On CNC lathes, holders also connect driven tools to the turret's power drive, allowing the lathe to perform milling, drilling and tapping as well as turning.

The holder is the interface between the machine and the cutting tool and selecting the correct holder is essential for tool accuracy, surface finish, tool life and safe operation.

This product category covers static VDI holders, static & driven tool holders for specific machine brands and angle heads.

This category is divided into three main sub-categories:

• VDI Static Tool Holders are the standard cylindrical-shank holders that mount in VDI (Verein Deutscher Ingenieure) turret bores and are used for static (non-rotating) turning, boring & drilling operations on a wide range of CNC lathes

• Static & Driven Tool Holders are the brand-specific holder families (Mazak, Citizen, Star and similar) that include both fixed and power-driven holders matched to a particular machine's turret interface

• Angle Heads are attachments that redirect the drive of a driven holder by 90 degrees or another angle, allowing a driven tool to cut on a face or side that the turret cannot reach directly.

Each sub-category serves a different machine and application requirement.

VDI (from the German engineering standard) is the most widely used interface for mounting tool holders on CNC turning-centre turrets.

A VDI holder has a cylindrical shank that slides into a matching bore on the turret station and is clamped in place, with a radial serrated coupling that locates the holder angularly and on driven stations, transmits the drive torque.

The VDI system allows quick tool changes and a high degree of standardisation across machine brands.

Here we list VDI holders in a range of shank sizes (referred to by the cylindrical shank diameter - 20 mm through to over 70 mm).

The VDI size is fixed by the machine turret, so the holder shank size must match the turret station.

Static tool holders hold a cutting tool in a fixed position while the workpiece rotates against it (they are used for turning, facing, boring, grooving, parting and static drilling). The tool does not rotate.

Driven (or "live") tool holders carry a rotating cutting tool (a drill, end mill, tap or reamer) driven by the turret's power drive, allowing the lathe to perform milling, drilling, tapping and cross-milling on a stationary workpiece.

A machine fitted with driven tooling can complete a part in a single setup that would otherwise require a separate milling machine (the defining feature of a mill-turn centre).

The Static & Driven category section at Milo Tools includes both types, matched to the machine's turret and drive specification.

An Angle Head is an attachment fitted to a driven tool holder that redirects the tool's rotation by 90 degrees (or another angle), allowing a driven tool to cut on a face or side that the turret cannot reach directly.

On a lathe, a driven holder normally drives a tool along the spindle axis (axial drilling/tapping) or perpendicular to it (cross-drilling/milling).

An angle head allows the same driven station to drive a tool facing the end face of the part, milling a slot on a shoulder, or reaching an angled face (operations that would otherwise require a separate setup or a Y-axis machine).

Angle heads expand the capability of a driven turret without needing a different machine and are widely used on mill-turn centres for one-hit machining of complex parts.

BMT (Bolt-Mount Turret) is a bolt-on turret interface used on many modern CNC lathes.

Unlike VDI, where a cylindrical shank slides into a bore, BMT holders bolt directly to the flat face of the turret with a dowel or serrated location for angular accuracy.

The BMT interface is more rigid than VDI for static tooling and is increasingly fitted to newer machines. We offer BMT holders in a range of sizes (BMT 45, BMT 55, BMT 65, BMT 75 and BMT 85) referring to the bolt circle and interface dimensions, with larger numbers fitted to larger machines.

Some BMT turrets also offer a driven variant (BMT 55/65/75 BIG DRIVE & BMT EM), allowing driven tooling to be bolted on.

BMT and VDI holders are not interchangeable as the turret is built for one or the other.

In addition to VDI & BMT our category lists holders by cylindrical shank size: 20 mm, 25 mm, 30 mm, 32 mm, 35 mm, 40 mm, 44 mm, 50 mm, 54 mm, 55 mm, 60 mm, 65 mm, 68 mm & 70 mm.

These are holders that mount in a cylindrical bore on the turret (a straight-shank interface, distinct from the VDI serrated coupling) and the shank diameter must match the turret station.

This interface is common on certain European and Japanese lathes including CMZ and machines using a cylindrical-shank turret.

As with VDI & BMT the shank size is fixed by the machine because the holder shank must match the turret bore.

If you are unsure which interface your machine uses, our engineers can advise from the model details.

A right-hand holder presents the cutting tool so that it cuts when fed towards the chuck (from the tailstock end towards the headstock), which is the conventional direction for most turning operations.

A left-hand holder cuts when fed away from the chuck (from the headstock end towards the tailstock).

The hand of the holder matters for operations such as parting, grooving and back-boring where the feed direction and the tool approach determine which holder is needed (for example, back-working on a sub-spindle often requires a left-hand orientation). Our category page here lists right-hand and left-hand variants across the holder ranges.

Selecting the correct hand ensures the tool approaches the workpiece correctly and the cutting forces are directed into the holder's strongest axis.

Overhead (or upside-down) holders present the cutting tool with the tool face pointing upwards, so the tool cuts the workpiece from below while the chip falls away downwards.

This orientation is used for applications where chip control is difficult (the chips fall clear of the cut by gravity rather than being carried around the workpiece) and for certain back-working operations on sub-spindles where the tool must approach the part from below.

Overhead holders are also used on machines where the turret is inverted or where access is from the underside of the workpiece.

Our category lists overhead/upside-down variants within the VDI static range for applications that require this orientation.

Selecting the correct holder requires knowing your machine's turret interface (VDI shank size, BMT size or cylindrical shank diameter), the type of operation (static turning, boring, drilling or driven milling/tapping), the tool being held (square-shank turning tool, boring bar, drill, tap or end mill), the orientation (axial, radial, right-angle) and any special features (overhead, multi-seat, tiltable, custom).

The machine dictates the turret interface, the turret interface dictates the holder family and the operation dictates the holder type within that family.

For brand-specific holders (Mazak, Citizen, Star & similar) the exact machine model identifies the correct holder.

Our engineers can help you identify all of these and specify the correct holder.

Yes.

Our team includes time-served engineers who can help you select the correct lathe tool holder for your machine and application.

Whether that's identifying your turret interface (VDI, BMT or cylindrical shank), choosing between static and driven holders, matching a holder to a turning tool, boring bar or drill, specifying an angle head for a restricted-access operation or selecting a brand-specific holder for a Mazak, Citizen, Star or other turning centre.

We can advise on the correct hand, orientation and special features for your job.

You can reach us by phone, online chat or email with your machine model and the operation you need to perform and we will be happy to help you specify the correct holder.