Slim 90° Right Angle Head (DK90-BT40 ER Mini Nut Series)

Slim 90° Right Angle Head (DK90-BT40 ER Mini Nut Series)

The DK90-BT40 ER Mini Nut Series (including ER11M, ER16M, ER20M, and AER25M) is a compact, deep-reach 90-degree right angle head designed specifically for narrow clearance side milling, deep cavity drilling, and internal bore tapping on BT40 vertical machining centers (VMC). By utilizing low-profile mini-nut collet spindles, this series reduces the head’s overall swing/passing diameter down to D55 mm, preventing interference when operating in tight workpiece pockets where standard angle heads cannot fit.


Featuring extended projection lengths up to 210 mm and a high-rigidity structural body, the DK90-BT40 Mini Nut series combines long-reach capability with cutting stability, enabling single-setup multi-face operations for complex mold bases and aerospace structural frames.


Key Technical Features and Material Standards

  • Ultra-Slim Profile & Mini Nut Design: Equipped with M-type mini collet nuts (ER11M, ER16M, ER20M, AER25M) that eliminate protruding wrench flats. This design reduces the maximum swing clearance diameter by up to 35% (down to D55 mm on ER11M models), granting access to narrow slots and deep internal walls.
  • High-Rigidity Casing Construction: The main body shell is manufactured from high-strength alloy casting, subjected to stress-relief annealing and cryogenic stabilization. This structure absorbs cutting vibration during deep-reach overhang operations while maintaining thermal stability.
  • Gleason Precision Ground Bevel Gears: The drive mechanism utilizes Gleason ground spiral bevel gears in 20CrMnTi Alloy Steel. Carburized and quenched to HRC 58-62 and ground to ISO Grade 4 precision, the gears deliver transmission backlash ≤ 15 arcmin and operational noise ≤ 70 dB under full load.
  • Preloaded Precision Bearings: Supported by high-precision P4 class angular contact ball bearings (NSK/FAG), ensuring rigid rotational stability and spindle nose runout ≤ 0.005 mm.

2D/3D Technical Drawings and CAD Download Center

slim 90° right angle head (dk90 bt40 er mini nut series)

Technical Specifications

ModelInput ShankSpindle OutputGage Length (L)Max. SpeedGear RatioPassing Dia. (D)Clamping RangeTapping CapacityMax. TorqueNet WeightStock Status
DK90-BT40-ER11M-60BT40ER11M60 mm6,000 RPM1:1D55 mmØ1.0 – Ø7.0 mmM5 – M68.8 Nm4.828 kgAlways in Stock
DK90-BT40-ER11M-100BT40ER11M100 mm6,000 RPM1:1D55 mmØ1.0 – Ø7.0 mmM5 – M68.8 Nm5.150 kgAlways in Stock
DK90-BT40-ER11M-140BT40ER11M140 mm6,000 RPM1:1D55 mmØ1.0 – Ø7.0 mmM5 – M64.8 Nm5.480 kgAlways in Stock
DK90-BT40-ER11M-210BT40ER11M210 mm6,000 RPM1:1D55 mmØ1.0 – Ø7.0 mmM5 – M68.8 Nm6.009 kgAlways in Stock
DK90-BT40-ER16M-100BT40ER16M100 mm8,000 RPM1:1D77 mmØ1.0 – Ø10.0 mmM5 – M818.0 Nm5.828 kgAlways in Stock
DK90-BT40-ER16M-170BT40ER16M170 mm8,000 RPM1:1D76 mmØ1.0 – Ø10.0 mmM6 – M1035.0 Nm6.200 kgAlways in Stock
DK90-BT40-ER20M-100BT40ER20M100 mm6,000 RPM1:1D85 mmØ1.0 – Ø13.0 mmM5 – M1030.0 Nm3.500 kgAlways in Stock
DK90-BT40-ER20M-150BT40ER20M150 mm6,000 RPM1:1D85 mmØ1.0 – Ø13.0 mmM5 – M1030.0 Nm6.000 kgAlways in Stock
DK90-BT40-ER20M-180BT40ER20M180 mm6,000 RPM1:1D85 mmØ1.0 – Ø13.0 mmM5 – M1030.0 Nm6.300 kgAlways in Stock
DK90-BT40-AER25M-100BT40AER25M100 mm6,000 RPM1:1D95 mmØ1.0 – Ø16.0 mmM6 – M1446.0 Nm5.566 kgAlways in Stock
DK90-BT40-AER25M-150BT40AER25M150 mm6,000 RPM1:1D95 mmØ1.0 – Ø16.0 mmM6 – M1446.0 Nm5.797 kgAlways in Stock

Quality Assurance and Testing Standards

Before dispatch, every DK90-BT40 ER Mini Nut series angle head undergoes a 100% Quality Inspection Protocol:

  • Static and Dynamic Runout Test: The spindle taper runout is measured with a high-precision dial indicator. Maximum runout is held to ≤ 0.005 mm at the spindle nose and ≤ 0.015 mm at 4D distance.
  • 60-Minute Continuous Run-In: Tested continuously at full rated speed for 60 minutes. The housing temperature rise must remain ≤ 25°C above ambient temperature to verify lubrication and gear alignment.
  • Anti-Backlash Calibration: Verified with angular encoders to confirm transmission backlash remains ≤ 15 arcminutes.

Target Industries and Industrial Applications

  • Deep Mold and Die Cavities: Machining internal side-walls, slider ribs, and angled ejector pin holes in deep mold bases where standard collet nuts collide with the workpiece.
  • Aerospace Ribs and Frames: Side slotting, pocketing, and drilling on narrow structural aluminum or titanium frames requiring slim cutter clearance.
  • Automotive Engine and Pump Housings: Finishing lateral internal features, valve pockets, and oil passages in complex casting enclosures.

CNC Machine Compatibility

Optimized for medium-to-large Vertical Machining Centers (VMC) and Horizontal Machining Centers (HMC). Compatible spindle interfaces include:

  • Spindle Standards: BT40 / BBT40 (Face & Taper double contact) / SK40 / HSK63A.
  • Typical Machine Brands: Compatible with Haas, Mazak, Okuma, Doosan / DN Solutions, Makino, and Hurco machine tools.

B2B Industrial Packing and Shipping Standards

  • Anti-Rust Protection: Coated with premium anti-rust oil and vacuum-sealed in a heavy-duty VCI (Vapor Corrosion Inhibitor) bag with moisture desiccant packs.
  • Shock Absorption: Nestled inside custom-contoured, high-density EPE shockproof foam blocks to prevent shifting or drop impact during courier transport.
  • Outer Casing: Packed in an export-grade, double-wall corrugated heavy-duty carton or an ISPM 15-compliant, Fumigation-Free Plywood Case depending on weight requirements.
  • HS Code: 8466.10.10.00 or 8466.30.00.90.
  • Lead Time: Standard models are shipped within 5-7 working days. Custom positioning blocks (G-distance) are completed and shipped within 15-20 working days.
  • Shipment Ports: Shanghai / Ningbo / Tianjin Port, China.
  • Incoterms Supported: FOB, CIF, EXW, FCA, DDU, DDP.
  • Express Delivery: Shipped via international air couriers (DHL, FedEx, UPS) with delivery to Europe and North America within 3-5 business days.

Technical Setup and Stop Block Alignment Guide

codeText

       ┌──────────────────────────────────────┐
       │     MACHINE TOOL SPINDLE FACE        │
       └──────────────────┬───────────────────┘
                          │ (Spindle Centerline)
                          │ 
                          ▼◄──────  G  ──────►[STOP BLOCK]
                       ┌─────┐                    │
                       │Taper│                    │ (Locking Bore)
                       └─────┘                    ▼
                          │               ┌───────────────┐
                     ┌────┴────┐          │ Positioning   │
                     │  Body   ├──────────┤ Pin (D18/D20) │
                     │  Casing │          └───────────────┘
                     └─────────┘
  1. Stop Block Mounting: Securely bolt the dedicated stop block (retaining block) to the front face of the VMC machine spindle.
  2. Verify Center Distance (G-Dimension): Confirm that the center-to-center distance between your machine spindle and the positioning pin socket corresponds precisely to your ordered G-Distance (commonly 65mm, 80mm, or 110mm).
  3. Indicate Side Runout: Chuck a ground test arbor into the ER mini nut collet. Sweeping a dial indicator along the arbor horizontally, adjust the stop block’s locking bolts until the parallelism is aligned within 0.015 mm per 100mm.
  4. Confirm ATC Clearances: Run a manual tool changer (ATC) test cycle at low speed to ensure the automatic arm smoothly grabs, inserts, and releases the BT40 taper without physical interference.

Technical FAQ

A: The ER Mini Nut (M-type) series features an internal-thread cylindrical nut design without external hex flats. This significantly reduces the outer diameter of the spindle output head (e.g., D55 mm on ER11M compared to D75 mm on standard ER11), allowing the angle head to enter deeper, narrower cavities without body collision.

A: As the Gage Length (L) extends to 140 mm on slim D55 mm bodies, long-reach physical leverage increases. Rating maximum torque to 4.8 Nm prevents torsional chatter and tool deflection during deep cavity milling, protecting internal bevel gears and maintaining surface finish.

A: Yes. M-type mini nuts require a specialized castle-type or castellated spanner wrench that engages the front slots of the nut rather than external hex sides. Each DK90-BT40 Mini Nut angle head ships with the appropriate M-type spanner wrench.

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