3KD Three-Jaw Large Through-Hole Power Chuck
The 3KD is a three-jaw power chuck with a large through-hole, made for lathes that feed bar stock or long tube through the spindle rather than loading one part at a time. The through-hole is what makes bar work possible: the material passes through the chuck and the spindle, so a long bar is machined in repeated cycles...
What This Machine Does
The 3KD is a three-jaw power chuck with a large through-hole, made for lathes that feed bar stock or long tube through the spindle rather than loading one part at a time. The through-hole is what makes bar work possible: the material passes through the chuck and the spindle, so a long bar is machined in repeated cycles with only a short feed between them. Three jaws self-centre round stock, which is why this is the standard chuck for turned shaft and bush work. Clamping force is high and repeat positioning accuracy is close, so the chuck holds its grip through interrupted cuts and puts the part back in the same place after each open and close, which is what automatic production needs. The chuck is stable at speed and built for continuous running. The range covers 3KD-06 through to 3KD-24 in mounting sizes from A5 to A20, with body diameters from 170mm to 610mm.
Why Buyers Choose This Machine
- Large through-hole lets bar and tube pass through the spindle for continuous bar work
- Three self-centring jaws grip round stock without setting each jaw individually
- High clamping force holds the part through interrupted and heavy cuts
- High repeat positioning accuracy returns the part to the same place after every cycle
- Stable at high speed so spindle speed is not limited by the workholding
- Range from 3KD-06 to 3KD-24 covers small turned parts through to large diameter work
- Camlock mounting sizes from A5 to A20 suit a wide range of lathe spindle noses
Where 3KD Three-Jaw Large Through-Hole Power Chuck Earns Its Place
Problems It Solves
- Small through-hole chucks force long bar to be cut into short billets and loaded one at a time
- Manual scroll chucks cannot be clamped and released inside an automatic cycle
- Clamping force that varies from cycle to cycle lets the part pull out under a heavy cut
- Chucks that lose repeat position force the tool offsets to be reset between parts
- Workholding that is unstable at speed limits the surface speed you can actually run
Who It Is For
- CNC turning shops running bar fed production
- Machine shops turning tube and pipe components
- Machine tool rebuilders and integrators fitting workholding
- Distributors supplying lathe accessories to turning shops
Application Scenarios
- Bar feeding work on CNC turning centres
- Turning long tube and pipe passed through the spindle
- Automatic and lights-out production where part position must repeat
- Second operation work on shafts and bushes
- Retrofitting a manual lathe onto power clamping for higher output
Technical Detail
Technical Features
- Three-jaw self-centring power chuck design
- Large through-hole for bar and tube feeding
- High speed stability
- High accuracy of repeat positioning
- High clamping force suitable for automatic production
- Strong and durable body construction
- Camlock mounting sizes A5 A6 A8 A11 A15 and A20 across the range
Specifications
| Machine type | Three-jaw large through-hole hydraulic power chuck |
|---|---|
| Models | 3KD-06 3KD-08 3KD-10 3KD-12 3KD-15 3KD-18 3KD-21 3KD-24 |
| Body diameter A | 170mm 3KD-06 210mm 3KD-08 260mm 3KD-10 315mm 3KD-12 405mm 3KD-15 455mm 3KD-18 530mm 3KD-21 610mm 3KD-24 |
| Mounting | A5 A6 A8 A11 A15 and A20 according to model |
| Body height B | 81mm 3KD-06 91mm 3KD-08 100mm 3KD-10 110mm 3KD-12 133mm 3KD-15 and 3KD-18 140mm 3KD-21 147mm 3KD-24 |
| Through-hole C | 91mm 3KD-06 103mm 3KD-08 113mm 3KD-10 126mm 3KD-12 154mm 3KD-15 161mm 3KD-18 181mm 3KD-24 in H6 |
| Jaw count | Three self-centring jaws |
| Application | Automatic production and bar fed turning |
Figures above are taken from the product information we hold. Send us your application and we will confirm the exact specification for the model quoted.
How It Is Built and What Can Be Changed
Operations Performed
- Turning
- Bar feeding
- Boring
- Facing
Quality Control
- Through-hole machined and checked to H6 tolerance
- Jaw repeat positioning accuracy verified on assembly
- Clamping force checked on the assembled chuck
- Body run-out checked on the mounting face and register
- Chuck run at speed to confirm stability before packing
Customisation Options
- Chuck size selected from 3KD-06 to 3KD-24 by workpiece and bar diameter
- Mounting specified to match your lathe spindle nose from A5 to A20
- Soft or hard jaws quoted for the work you hold
- Draw tube adapter specified for your machine's cylinder
How It Compares With the Alternatives
| 3K three-jaw hollow power chuck | Both are three-jaw power chucks; the 3KD is the large through-hole version for feeding bigger bar and tube through the spindle |
|---|---|
| 4K four-jaw hollow power chuck | Four jaws suit irregular and square work; the 3KD self-centres on round stock and is faster to load for shaft and tube production |
| Manual scroll chuck | A manual chuck has to be tightened by key between parts, which rules out automatic cycles and lets the clamping force vary with whoever loads it |
Running the Machine
Step 1
Check the bar or tube diameter will pass through the chuck and spindle bore
Step 2
Mount the chuck to the matching spindle nose size and check run-out on the register
Step 3
Connect the draw tube to the machine cylinder and set the clamping pressure
Step 4
Fit jaws suited to the work and bore soft jaws in place for concentric holding
Step 5
Clamp a test part and check repeat position over several open and close cycles
Step 6
Keep the jaw slots and internal mechanism greased to the maintenance schedule
Step 7
Recheck clamping pressure after any change of jaw or workpiece diameter
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Questions About 3KD Three-Jaw Large Through-Hole Power Chuck
Which 3KD size do I need?
Choose by workpiece and bar diameter and by your spindle nose. Body diameters run from 170mm on the 3KD-06 to 610mm on the 3KD-24. Send us your lathe model and the bar diameter you feed and we will confirm.
What mounting will fit my lathe?
The range covers A5, A6, A8, A11, A15 and A20 mountings. Tell us your spindle nose designation and we will match the chuck to it.
What is the advantage of the large through-hole?
Bar and tube pass through the chuck and spindle, so long material is machined in repeated cycles with a short feed between them rather than being cut into billets and loaded one by one.
What clamping force will I get?
Clamping force depends on the chuck size and on the draw bar pull from your machine cylinder. Send us the chuck size and your cylinder data and we will confirm the working figures.
Are soft jaws supplied with the chuck?
Jaws are specified against the work you hold. Tell us your part diameters and whether you want soft or hard jaws and we will quote them with the chuck.
How is the chuck packed and shipped?
Chucks are packed individually and shipped from our storehouse in Xi'an. Tell us your port and quantity and we will quote FOB CFR or CIF.
What are your payment terms?
30 percent by T/T on order and 70 percent before shipment, or an irrevocable L/C at sight.
Request a Quote on the 3KD Three-Jaw Large Through-Hole Power Chuck
Send us the work you need it to do, the voltage on your site and the port you ship to. We will come back with the model, the tooling and the lead time.