A2003251 Ultra-High-Power Heavy-Duty Milling Spindle
HSK-A63 | 20 kW | 48 N·m | Center Through Coolant | Designed for Gantry & Large Machining Centers

The A2003251 is a top-tier, ultra-high-torque electric spindle engineered for the most demanding heavy-duty milling and engraving applications on large machining centers, gantry mills, and high-performance vertical mills. Delivering a massive 20 kW of power and up to 48 N·m of torque in Y-configuration, it is built to handle aggressive machining of steels, stainless steels, cast iron, and high-temperature alloys with exceptional rigidity, thermal stability, and reliability.


Technical Overview

Designed for high-productivity environments where material removal rate and process stability are critical, the A2003251 combines extreme power with precision engineering. Its HSK-A63 tool interface and enormous drawbar force (18,000 N) ensure secure tool clamping for heavy cutting, while the integrated center through coolant (up to 7 MPa) enables efficient deep-hole drilling and milling. Compatible with 380V single-winding drives such as Siemens and other major third-party systems, it offers flexibility for integration into a wide range of high-end machine tools.

Core Performance Advantages

  • Extreme Power & Torque: With 20 kW continuous power and a groundbreaking 48 N·m torque (Y-connection), this spindle delivers relentless cutting force for heavy roughing, face milling, and deep slotting.
  • Ultra-High Rigidity & Stability: Exceptional radial stiffness (750 N/µm) and axial stiffness (250 N/µm) provide an ultra-stable platform, minimizing vibration and deflection to maintain accuracy and surface finish under extreme loads.
  • Advanced Thermal Management: A high-flow cooling system (>10 L/min) combined with center through coolant (7 MPa) effectively controls heat at both the spindle body and cutting zone, reducing thermal growth for consistent precision over long cycles.
  • Heavy-Duty Tool Interface: Equipped with HSK-A63, a robust taper designed for high-power transmission and precise tool positioning in heavy machining.
  • Superior Precision & Balance: A precision-ground taper (runout ≤2.0 µm), G0.4 dynamic balance grade, and low vibration (≤1.0 mm/s) ensure smooth, quiet operation essential for fine finishing and extended tool life.
  • Flexible Drive Compatibility: 380V single-winding motor design allows integration with Siemens and other industry-standard third-party drives, offering broad system compatibility.

Detailed Technical Specifications

CategoryParameterSpecification / Value
General InformationDesignationElectric Spindle
Model A2003251-PNP
Tool HolderHSK-A63
LubricationGrease
MountingVertical
Drive MethodBuilt-in Motor
Encoder SignalSine Wave / 160-tooth
Tool Change SignalPNP / NO
Dynamic BalanceG0.4
Warranty1 Year
Spindle Net Weight55 kg
Gross Weight (Wooden Case)62 kg (Spindle: 55kg + Case: 7kg)
PerformanceMax Speed20,000 rpm
Radial Stiffness750 N/µm
Axial Stiffness250 N/µm
Taper Runout≤ 2.0 µm (at 25mm); ≤ 8.0 µm (at 300mm)
Face Runout≤ 2.0 µm
Vibration Velocity≤ 1.0 mm/s
Rated Power (Y or Δ)​20 kW
Rated Torque (Y / Δ)​48 N·m / 27.3 N·m
Drawbar Force18000 ± 2000 N
System Interfaces & CoolingThrough-Spindle Coolant Pressure7 MPa (Max)​
Main CoolingOil/Water Coolant
Flow >10 L/min, Cooling Power >1.5 kW, Max. Inlet Temp. 30°C
Air Seal Pressure2 – 7 bar
Taper Clean Air Pressure2 – 7 bar
Tool Release Oil Pressure5 – 7 MPa

rimary Applications

This spindle is engineered for large-scale, high-power machining, including:

  • Heavy-duty milling on gantry machining centers and large vertical mills.
  • Roughing and semi-finishing of large molds, dies, and aerospace structural components.
  • Deep cavity machining and high-efficiency face milling.

Value Proposition

The A2003251 is built to be the cornerstone of your heavy machining capability. It transforms large machine tools into highly productive systems by enabling faster material removal, ensuring accuracy through unmatched stiffness, and providing reliable, continuous performance for the most challenging industrial applications.


Power Your Largest Machining Challenges. Contact our engineering team today to discuss integration options and configure the A2003251 Ultra-High-Power Spindle for your gantry, vertical, or large machining center.