Doosan Tool Holders

BMT (Base Mount Tooling) is a standardised turret mounting interface used on CNC lathes. BMT defines the bolt pattern, locating features and dimensions by which a tool holder attaches to the flat face of the lathe turret. The number (45, 55, 65, 75, 85) refers to the size of the BMT interface ( larger numbers indicate larger turrets with more mounting bolts and greater load capacity).

BMT 65 is the specific BMT size used on the majority of Doosan lathe models in this range. The BMT 65 interface consists of a flat mounting face on the turret with a pattern of mounting holes and locating dowels. The tool holder has a matching flat base with bolt holes and reamed dowel holes. The holder is bolted to the turret face with dowel pins providing precise radial location so the holder is positioned repeatably every time it is mounted.

Our product listings identify each Doosan model with its turret specification, for example, "PUMA 2600 -- (Star-Type 12ST - BMT 65)" means the PUMA 2600 uses a BMT 65 turret mount with a Star-Type 12-station drive coupling. The "Star-Type" refers to the internal drive coupling geometry that transmits power from the turret servo motor to driven tool holders (a star-shaped (serrated) coupling on the drive shaft engages with a matching socket on the driven tool holder).

BMT sizes in the broader range: While Doosan models in this category predominantly use BMT 65, our full static & driven tool holder range also includes BMT 45, BMT 55, BMT 55 BIG DRIVE, BMT 55 EM, BMT 65 BIG DRIVE, BMT 65 EM, BMT 75, BMT 75 BIG DRIVE, BMT 75 EM and BMT 85. The "BIG DRIVE" designation indicates a larger-diameter drive coupling for higher torque transmission and "EM" denotes an enhanced-mount variant. If your Doosan uses a different BMT size (e.g. a smaller PUMA model with BMT 55) you need the holder matching that size (a BMT 65 holder will not fit a BMT 55 turret).

The Star-Type drive coupling comes in 12ST (12-station) and 16ST (16-station) variants. The Doosan range includes both: most PUMA models use Star-Type 12ST, while the Dugard 52 TT/TTT SY uses Star-Type 16ST. The driven tool holder's drive socket must match the turret's star-type coupling: a 12ST holder fits a 12ST turret, a 16ST holder fits a 16ST turret.

Use our internal site search or left hand product filters to narrow down your search as our Doosan range is quite extensive.

Our Doosan Machine Tools category covers a wide range of Doosan CNC lathe models, all using the BMT 65 turret mount with Star-Type 12ST or 16ST drive couplings.

The models include:

PUMA series (the core Doosan turning range):

• PUMA 2100, PUMA 2600, PUMA 300 M, PUMA 300 MS, PUMA 3100: standard CNC lathes and milling-equipped variants (M = milling-capable, MS = milling with sub-spindle)

• PUMA INVERTURN 3000: inverted vertical spindle lathe

• PUMA MX 2000, PUMA MX 2500, PUMA MX 2600: multi-axis (MX) turn-mill centres with Y-axis and sub-spindle capability

• PUMA TT 2000, PUMA TT 2500: twin-turret (TT) lathes with two independent turrets for simultaneous upper/lower machining

• PUMA V400M: vertical milling lathe

• PUMA VT 350 TM, PUMA VT 450M: vertical turning centres

Each PUMA model on our site is listed with its turret specification: Star-Type 12ST with BMT 65. This means the same BMT 65 tool holders fit across the PUMA range (a holder for a PUMA 2600 will also fit a PUMA 2100, PUMA 300 M, PUMA MX 2000, etc, because they all share the same BMT 65 / Star-Type 12ST interface).

Cross-brand compatibility:

The BMT 65 / Star-Type 12ST interface is not exclusive to Doosan. The same tool holders fit machines from other manufacturers that use the identical turret specification, including:

• Haas: DS 30Y, ST 20Y, ST 25Y, ST 30Y, ST 35Y (Y = Y-axis models)

• Hwacheon: CUTEX 240, HI TECH 200/300/350/400/450, T2, VT 450 M

• Hyundai WIA: L2100Y, L2600Y, L300 series (LMA/LMC/LMSA/MA/MC/MSA/MSC), LM 2000/2500 TTM/TTMS/TTSY, LV500, SKT series

• Romi: GL 350 M, GL 400 M, VTL 500

• SMEC Samsung: PL and SL series

• Tongtai: TD 2000 YBC

• Victor-Taichung: VTURN A 26 and S 26

• Dugard: 52 TT, TTT SY (Star-Type 16ST - different drive coupling)

Each product page lists the full set of compatible machines. For example the BMT 65 Radial Tool Holder (SKU 06304200) lists 88 compatible machines. This cross-compatibility means a single tool holder can serve multiple machines across different brands if they share the same BMT 65 / Star-Type 12ST specification.

The range includes multiple tool holder geometries, each positioning the cutting tool in a specific orientation relative to the turret and workpiece. The type codes follow a systematic naming convention:

LT-S / Tool holder straight: The cutting tool is held in line with the holder body (the tool axis is parallel to the holder's mounting axis). Straight holders present the tool axially (along the spindle centre line) for operations like end-facing, axial drilling or axial milling.

LT-S OFS / Tool holder straight offset: Similar to LT-S but the tool output is offset from the holder centre line (used when the tool needs to reach past an obstruction or when the turret station geometry requires an offset).

LT-A / Tool holder angle 90°: The cutting tool is oriented at 90° to the holder body (the tool axis is perpendicular to the holder mounting axis). This positions the tool radially (pointing toward the spindle centre) for cross-milling, slotting or radial drilling.

LT-A OFS / Tool holder offset angle 90°: 90° angle holder with the tool output offset from centre.

LT-A ST / Slotting tool 90°: A 90° holder configured specifically for slotting (holding a slotting tool or saw blade for cutting slots or grooves across the workpiece).

LT-T / Tool holder tiltable: The tool angle can be adjusted — the holder has a pivoting joint that allows the tool to be set at various angles, useful for compound-angle machining or when the part geometry requires a non-standard tool approach angle.

TH-RAD / Radial tool holder: A static holder that clamps a square-shank tool (e.g. 25×25mm) in a radial orientation (the tool extends radially toward the spindle). Used for external turning and facing. The BMT 65 Radial Tool Holder (SKU 06304200, 25×25 output) is a TH-RAD type.

TH-AX / Axial tool holder: A static holder clamping a square-shank tool in an axial orientation (the tool extends along the spindle axis. Used for end-facing and axial operations).

TH-BRB / Boring bar holder: A static holder that clamps a cylindrical boring bar, held axially or radially, for internal turning (boring) operations. The boring bar passes through the holder and is clamped by a set screw or collet.

TH-CUT / Cutting holder: A static holder specifically for parting/grooving tools (holds the parting blade in the correct orientation for cut-off or grooving operations).

Double holders (LT-S2, LT-A2, etc): Hold two tools simultaneously (allowing two operations from one turret station, increasing tool capacity without adding stations). Available in double-straight, double-angle, double-horizontal and double-vertical configurations.

All Mario Pinto driven tools in this range use the patented SUPERCOMPACT drive system. This is the internal mechanism that transmits rotational power from the turret's drive shaft to the cutting tool spindle inside the driven holder.

How conventional driven tools work: Most driven tool manufacturers use a drive key (a rectangular key) on the outside of the housing that engages with a keyway inside the gear shaft. The drive key transmits torque from the input shaft (connected to the turret drive) to the output shaft (connected to the cutting tool). The key and keyway are machined into the shaft, which removes material and creates stress concentrators (the shaft is weaker at the keyway and the gear is weaker where the key slot is cut). Under high torque or shock loading the key can shear or the shaft can crack at the keyway.

How SUPERCOMPACT works: The SUPERCOMPACT system couples the ground shaft and gear in a single operation using a square or hexagonal housing (the drive coupling is an integral multi-sided (square or hex) form rather than a separate key). The shaft and gear are ground to mate directly through the polygonal form, transmitting torque across the full cross-section of the shaft rather than through a single small key. This eliminates the keyway and no material is removed from the shaft so there are no stress concentrators.

Benefits of SUPERCOMPACT:

• Higher torque capacity: Torque is transmitted across the full polygonal contact area, not through a single key face. The shaft and gear can transmit more torque before failure

• Stronger shaft and gear: With no keyway machined into the shaft, the shaft retains its full cross-sectional strength. The gear is similarly not weakened by a key slot

• Better concentricity: The ground polygonal coupling provides more precise concentricity between input and output shafts than a key-and-keyway fit, which can have clearance and backlash. Better concentricity means less runout at the cutting tool directly improving machining accuracy

• Reduced backlash: The ground multi-sided coupling has minimal clearance between mating surfaces, reducing backlash in the drive train. This is important for operations like tapping (where backlash causes thread errors) and precision milling.

Two specific design features of the Mario Pinto driven tools affect performance and longevity:

High-precision bearings, single-side sealed: The driven tool spindle runs on high-precision bearings (typically angular contact or tapered roller bearings rated for high speed and axial load). These bearings are sealed on only one side, not both sides. The reason for this is that double-sealed bearings trap heat inside and prevent lubricant from circulating. By sealing only one side the bearing allows "heat and lubrication exchange, resulting in balanced grease and heat distribution." Heat generated by the rotating spindle at speed can migrate through the unsealed side and dissipate, while lubricating grease can redistribute within the bearing housing. This prevents localised overheating (which would degrade the grease and damage the bearing) and ensures the bearing runs at a more uniform temperature, maintaining consistent preload and accuracy.

Patented labyrinth seals: The external sealing of the tool holder uses Mario Pinto's patented labyrinth seal design. A labyrinth seal is a non-contact seal consisting of a series of intricate passages (the "labyrinth") between the rotating and stationary components. Coolant, chips and dirt would have to navigate a tortuous path through multiple chambers and turns to reach the internal bearings and gears. Unlike a simple rubber lip seal (which rubs against the rotating shaft, wears, and eventually leaks), a labyrinth seal has no rubbing contact as it relies purely on the geometric complexity of the passages to block contaminants. The product description states: "This prevents dirt and fluid from entering inside the tool extending the tool life." In a CNC lathe environment where high-pressure coolant and metal chips are constantly present, effective sealing is critical because bearing and gear failure from coolant ingress is one of the most common causes of driven tool failure.

Combined effect: The single-side-sealed bearings manage internal heat and lubrication, while the labyrinth seals manage external contamination. Together, they address the two main failure modes of driven tooling: internal thermal degradation and external contamination.

Our product listings specify the coolant type (the Doosan range products shown use "External coolant.") Coolant delivery to the cutting zone is critical for tool life, chip evacuation and surface finish.

Driven/static tool holders can route coolant in different ways:

External coolant: The coolant is delivered through a nozzle or port on the outside of the tool holder, spraying coolant onto the cutting tool from the exterior. The coolant stream hits the tool tip and workpiece from outside the holder. This is the simpler and less expensive option as the holder does not need internal coolant channels. External coolant is adequate for many operations but has limitations such as the coolant stream can be deflected by the rotating tool or chips and it may not reach the exact cutting edge reliably, especially in deep-hole drilling or internal milling where the tool is recessed.

Internal (through-tool) coolant: The holder has internal coolant channels that route coolant through the holder body and directly to the cutting tool, either through the centre of the tool (through-spindle coolant, for drills and end mills with coolant holes) or to a port immediately at the tool tip. Through-coolant delivers coolant at full pressure directly to the cutting edge providing superior cooling and chip flushing, particularly in deep-hole drilling where external coolant cannot reach the cutting zone. Through-coolant holders are more complex and expensive (requiring sealed internal channels and a rotary coolant coupling for driven tools) but are essential for deep-hole drilling, high-pressure coolant applications and production machining where tool life and chip control are critical.

The Doosan range products shown (SKUs 05100300, 05100600, 06304200) all specify "External coolant." This means these specific holders deliver coolant externally. If your application requires through-tool coolant (deep-hole drilling, high-pressure coolant) then you need a holder variant with internal coolant routing (these are available in the broader range and can be identified by the coolant specification in the product listing - designated "K-W" or similar in the product code, where K typically indicates coolant type).

Coolant code conventions: The product codes include coolant designations (e.g. "K-W" in "LT-S BMT65 DIN138-22 H46 K-W"). These codes indicate the coolant routing configuration (whether the holder has external only, internal/through or both). When selecting a holder you must match the coolant type to your application: external for general milling/drilling, through-coolant for deep holes and high-pressure requirements.

Included with each driven tool: The packaging for each Mario Pinto driven tool includes:

• The tool holder itself: fully assembled, tested & ready to mount

• Test report: the 60-minute test data (geometrical dimensions, temperature, noise/vibration) for that specific serial-numbered unit

• Maintenance manual: instructions for ongoing care, lubrication intervals, bearing inspection, and seal replacement

• Wrench: the specific wrench needed to mount and adjust the tool on the turret and to change cutting tools

• Greasing kit: the correct grade of grease and the grease fitting (nipple) for re-lubricating the bearings during scheduled maintenance

The packaging: includes a picture of the tool, a short description and a barcode on the outside of the box, allowing identification without opening the package (important for stores management and tool crib organisation)

Maintenance requirements

Driven tools are precision assemblies with rotating bearings and gears that require periodic maintenance:

Greasing: The bearings must be re-lubricated at the interval specified in the maintenance manual (typically every 500 to 2,000 hours of operation, depending on speed and duty). The included greasing kit provides the correct grease because using the wrong grease grade can damage the bearings. The grease fitting allows re-lubrication without disassembly. Over-greasing is as harmful as under-greasing because excess grease generates heat and can blow out the seals.

Seal inspection: The labyrinth seals should be inspected periodically for damage or clogging with swarf. A damaged seal allows coolant and contamination ingress, leading to rapid bearing failure. The seals are non-contact (labyrinth type) so they do not wear in normal operation but they can be damaged by impact or clogged with compacted debris.

Runout check: Periodically check the spindle runout with a dial indicator against the comments in the test report. If runout has increased significantly from the baseline test data the bearings may be wearing or preload may be lost, indicating the tool needs service.

Storage: When not in use, driven tools should be stored clean and lightly oiled to prevent corrosion of the precision bearing surfaces and gear teeth. The original packaging is designed for storage and the image and barcode allow identification without opening.

Selecting the correct tool holder requires matching five specifications to your machine and application:

1. Machine model and turret specification: Identify your exact Doosan model (e.g. PUMA 2600). The category page lists all Doosan models with their turret specification (e.g. "PUMA 2600 -- Star-Type 12ST - BMT 65"). You need a holder matching that BMT size (65 for most Doosan models) and drive coupling type (12ST or 16ST). The product page for each holder lists compatible machines so verify your model appears on the list. The BMT 65 Radial Tool Holder (SKU 06304200) lists 88 compatible machines including all the Doosan PUMA models.

2. Static or driven: Determine whether the operation requires a static holder (turning & the workpiece rotates) or a driven holder (milling/drilling & the tool rotates). Static holders are simpler and less expensive whereas driven holders contain the gear train and bearings. If you are doing conventional external/internal turning, facing or parting, you need a static holder. If you are milling flats, drilling cross-holes or tapping you need a driven holder.

3. Tool orientation (axial or radial): Determine whether the tool needs to approach the workpiece axially (along the spindle centre for end-face operations) or radially (across the workpiece, for side operations). Select LT-S/TH-AX for axial, LT-A/TH-RAD for radial. For radial holders note the left/right (L/R) orientation to ensure the tool extends on the correct side of the turret.

4. Tool output interface: Match the holder's output to your cutting tool's shank type: ER collet (ER32/ER40) for cylindrical-shank tools, Shell-Mill DIN138 for shell/face mills, square socket (25×25) for square-shank turning tools, or boring bar holder for cylindrical boring bars. The holder must accept the tools you already own or intend to purchase.

5. Coolant type: Determine whether your application requires external coolant (adequate for general work) or through-tool/internal coolant (required for deep-hole drilling and high-pressure applications). Select the holder with the matching coolant configuration.

Cross-machine flexibility: Because the BMT 65 / Star-Type 12ST interface is shared across many machines (Doosan PUMA range, Haas ST/DS series, Hwacheon, Hyundai WIA, etc.), a holder purchased for one machine can be reused on another if you change machines (provided the new machine uses the same BMT 65 / Star-Type 12ST specification). This is a significant advantage of the standardised BMT interface over proprietary turret mounting systems.