Hydraulic Indexing Chuck · Auto Indexing CNC Lathe Chuck
KORRETTO TK series hydraulic indexing chuck —the auto indexing chuck designed for CNC lathes processing valves, cross shafts, and multi-face components in a single setup. Indexing precision 0.003°, sizes Φ168–00mm, standard 6×60° or 8×45° indexing, with built-in indexing alarm on every model.
Hydraulic Indexing Chuck · Key Advantages
0.003° Indexing Precision —Mechanical Lock Guarantee
Precision is set by mechanical stop geometry, not hydraulic pressure. Repeat positioning 0.03mm after tens of thousands of cycles —no calibration drift over time.
One Setup Replaces 2– Operations
The auto indexing chuck completes 6×60° or 8×45° face machining in a single clamping under full CNC program control. One operator can supervise 3 machines simultaneously.
Indexing Alarm —Standard on All Models
Built-in indexing and clamping detection signals at every indexed position. If indexing or clamping is incomplete, the CNC stops automatically —safe for unattended production.
Robot-Ready Clamping Space
Wide, unobstructed chuck opening accommodates robotic arm loading/unloading. Fully compatible with most CNC lathes; custom spindle nose flanges available.
TK Series Hydraulic Indexing Chuck —Specifications
| Model | OD D (mm) | Chuck Bore D1 (mm) | Max Workpiece (mm) | Clamping Force (kN) | Stroke (mm) | Indexing Speed (rpm) | Weight (kg) |
|---|---|---|---|---|---|---|---|
| TK-168 | 190 | 168 | 136 | 10.6 | 9 | 70 | 15 |
| TK-203 | 216 | 203 | 164 | 11.3 | 15.2 | 82 | 24 |
| TK-225 | 240 | 225 | 190 | 11.3 | 15.2 | 95 | 30 |
| TK-256 | 276 | 256 | 210 | 14.5 | 19.1 | 105 | 42 |
| TK-305 | 330 | 305 | 260 | 14.5 | 19.1 | 130 | 61 |
| TK-400 | 416 | 400 | 350 | 31.4 | 30 | 175 | 120 |
| TK-460 | 490 | 460 | 410 | 31.4 | 30 | 205 | 161 |
| TK-570 | — | 570 | 460 | 56.5 | 42 | — | 306 |
| TK-680 | — | 680 | 560 | 56.5 | 42 | — | 413 |
| TK-850 | — | 850 | 720 | 66.3 | 55 | — | 661 |
| TK-1000 | — | 1000 | 860 | 80.0 | 65 | — | 1298 |
| TK-1200 | — | 1200 | 1060 | 80.0 | 65 | — | 1558 |
Standard indexing: 6×60° / 8×45°. Custom equal divisions available. · Indexing precision 0.003° · Repeat positioning 0.03mm (0.02mm high-precision option) · TK-168 to TK-460: standard stock; TK-570 and above: 20-day delivery.
How the Auto Indexing Chuck Works
The hydraulic indexing chuck integrates hydraulic clamping with a precision mechanical indexing mechanism. CNC program controls the full cycle —no manual intervention between faces.
Clamp
Hydraulic oil from the rotary oil distributor pressurizes the chuck during spindle rotation, maintaining clamping force throughout machining.
Index Command
CNC issues the indexing command. Hydraulic control valve switches circuits, chuck releases the workpiece for rotation.
Rotate & Lock
Chuck rotates workpiece to the programmed angle (e.g. 60°). Mechanical lock engages at the precision stop —independent of hydraulic pressure.
Confirm & Machine
Indexing alarm confirms position via CNC signal. Hydraulic pressure reapplied. Next machining operation begins automatically.
Why mechanical locking matters: Many indexing systems rely on hydraulic pressure to hold position, which can drift. The KORRETTO TK series uses a positive mechanical lock at each indexed position —precision is maintained even if hydraulic pressure fluctuates, and the position is physically locked rather than held by force alone.
Typical Applications —Workpieces & Industries
Valve Bodies
Ball valves, butterfly valves, safety valves —multi-port machining in one setup
Cross Shafts & Yokes
Universal joint cross shafts, drive yokes –-face or 6-face machining
Hydraulic & Pneumatic Manifolds
Complex port patterns on manifold blocks and cylinder bodies
Fire Protection Fittings
Multi-directional fittings, coupling bodies, angle connectors
Flanges & Large Valves
TK-850/1000/1200 heavy-duty indexing chucks for large valve bodies up to Φ1200mm
Auto Components
Differential parts, transmission housings, any component with indexed bolt-hole patterns
System Components —Complete CNC Lathe Integration
The hydraulic indexing chuck system integrates with your existing CNC lathe via 8 standard components
| # | Component | Function |
|---|---|---|
| 1 | Indexing Chuck Body | Workpiece clamping and auto-rotary indexing/positioning |
| 2 | Front Flange | Adapts chuck to CNC lathe spindle nose (A2-5 / A2-6 / A2-8 / flat nose) |
| 3 | Telescopic Connecting Rod | Oil passage connecting chuck body to the rotary oil distributor |
| 4 | Rear Flange | Mounts the rotary oil distributor to the lathe rear end |
| 5 | Rotary Oil Distributor | Distributes hydraulic oil to the rotating chuck without leakage |
| 6 | Indexing Alarm Mechanism | Standard on all models. Sends CNC signal confirming index/clamp completion at each position; auto-stops if incomplete |
| 7 | Oil Hose Assembly | Hydraulic lines between distributor and hydraulic power unit |
| 8 | Hydraulic Power Unit (optional) | Provides clamping and indexing hydraulic pressure; can use existing lathe hydraulics |
KORRETTO provides complete CNC ladder diagram redesign to integrate indexing signals into your existing CNC program —at no additional charge.
Customer Cases
Case 1 · Full Safety Valve Production Line Automation (German-Invested Manufacturer)
Customer produces a full range of safety valves with large workpiece size variation. Deployed TK-1000, TK-630, and TK-500 hydraulic indexing chucks with quick-change fixtures to cover entire valve production line. Fast changeover between models; compared to purchasing dedicated indexing machines, equipment investment savings exceeded several million RMB.
Case 2 · Stainless Steel Valve Exporter, Shandong (Doosan CNC Lathes)
Customer produces hundreds of stainless steel valve types for export —extremely high product consistency requirements. Deployed 23 indexing chucks on Doosan CNC lathes. Reject rate reduced significantly; consistency improved. Originally 3 machines and 3 operators for one workpiece; now one machine completes all operations in one setup. One operator supervises 3 machines —productivity increased 300%.
Frequently Asked Questions
Q: What is a hydraulic indexing chuck and how does it differ from a standard hydraulic chuck?
A: A hydraulic indexing chuck adds an automatic rotary indexing mechanism to hydraulic clamping. While a standard hydraulic chuck only clamps and releases, the indexing chuck also rotates the workpiece to precise angular positions (e.g. 60° or 45° increments) under full CNC control —all without removing the workpiece. This replaces 2– separate setups on separate machines with a single automated cycle.
Q: What indexing precision can I expect from the TK series?
A: Indexing precision is 0.003°; repeat positioning accuracy is 0.03mm (0.02mm for high-precision versions). Precision is guaranteed by mechanical locking —not hydraulic pressure —so it stays stable after tens of thousands of indexing cycles with no calibration required.
Q: What workpieces are best suited for an indexing lathe chuck?
A: Any workpiece needing machining on 2 or more angular faces. Classic applications: valve bodies (ball valve, butterfly valve, safety valve), cross shafts, universal joint yokes, pneumatic/hydraulic manifold blocks, fire protection fittings, and flanges. For large workpieces up to Φ1200mm, the TK-850/1000/1200 heavy-duty indexing chucks are used.
Q: What does the standard indexing alarm system do —is it really necessary?
A: All TK series indexing chucks include a built-in indexing and clamping detection mechanism as standard. It sends an electronic confirmation signal to the CNC controller at each indexed position. If indexing or clamping fails to complete correctly, the CNC automatically stops —preventing tool crashes and workpiece damage in unattended production. This makes the KORRETTO TK series safe for lights-out automation.
Q: Is this auto indexing chuck compatible with my CNC lathe brand?
A: The TK series is compatible with the majority of CNC lathes on the market. The spindle nose flange is adapted to your specific lathe (A2-5, A2-6, A2-8, flat nose, or custom interface). KORRETTO provides free CNC ladder diagram integration to connect indexing signals to your existing CNC program. Send us your lathe model and spindle specifications —our engineers will confirm compatibility within 1 business day.
Q: What is the difference between an auto indexing chuck and a manual indexing chuck?
A: An auto indexing chuck (hydraulic) indexes automatically under CNC program control —no operator action between positions, suitable for continuous unattended machining. A manual indexing chuck requires the operator to rotate and lock the workpiece by hand at each position. KORRETTO TK series are all automatic hydraulic indexing chucks. For manual indexing applications, our dividing heads and rotary tables are available.
Related Pages & Products
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