6 Jaw Power Chucks - Versatile Workholding for Machining Operations

Introduction to 6 Jaw Power Chucks

6 jaw power chucks are an important workholding tool for machining operations. They provide a secure and accurate method for holding round or odd shaped workpieces that need to be turned, milled or drilled. 6 jaw chucks get their name from having 6 independent jaws that can be adjusted to hold the workpiece securely and center it accurately. This gives them an advantage over 3 jaw scroll chucks which can sometimes struggle to center workpieces accurately.

Benefits of 6 Jaw Power Chucks

There are several key benefits that make 6 jaw power chucks a valuable addition to any machine shop:

• Accurate centering - Each jaw moves independently allowing delicate adjustment to center the workpiece perfectly. This is critical for precision machining operations.
• Secure holding - 6 jaws provide a very secure and rigid grip, essential for milling and drilling tough materials.
• Versatility - 6 jaw chucks can hold anything from round stock to hexes, squares, flats, plates and irregular shapes.
• Reduced runout - With precise centering and gripping, 6 jaw chucks minimize runout and improve finished part accuracy.
• Power operation - Hydraulic or pneumatic actuation allows high clamping forces to be applied easily.

Types of 6 Jaw Power Chucks

There are two main types of power operated 6 jaw chucks:

Hydraulic 6 Jaw Chucks

Hydraulic power provides the clamping force for these chucks. Hydraulic fluid is pumped into the chuck to force the jaws inwards and grip the workpiece. Hydraulic chucks can be actuated with a power pack or shop hydraulic system.

Benefits of hydraulic 6 jaw chucks:

• Very high clamping forces possible
• Ideal for high rigidity milling applications
• Self-centering hydraulic design options
• Compact size and low weight

Pneumatic 6 Jaw Chucks

Pneumatic 6 jaw chucks use compressed air to provide the actuation power. They are a lower cost alternative to hydraulic models and well suited for normal machining operations.

Benefits of pneumatic 6 jaw chucks:

• Simple and low maintenance design
• Quick acting for efficient workholding
• Lower initial cost than hydraulic
• Integrated pneumatic supply in machine reduces clutter

Key Features of 6 Jaw Power Chucks

Some important features to look for when selecting a 6 jaw power chuck include:

• Top jaws vs integral jaws - Top jaws are removable and interchangeable allowing quick changeover. Integral jaws are machined directly into the chuck body for rigidity.
• Hardened jaws - Hardened steel jaws prevent damage and wear to the critical clamping surfaces.
• Mounting - Backplate vs threaded spindle - Backplate mounting offers maximum rigidity. Threaded spindle allows quick changeover between chucks.
• Size range - Diameters available typically range from 100mm to 1,000mm. Consider the swing capacity needed.
• Actuation method - As covered earlier, hydraulic and pneumatic power provides the actuation force.

Workholding Tips for 6 Jaw Chucks

Here are some workholding tips when using 6 jaw power chucks:

• Clean the chuck mounting surfaces and workpiece before clamping.
• Use all 6 jaws evenly when gripping. This balances forces and reduces distortion.
• Bring up clamping force gradually until workpiece is securely held.
• For thin wall parts, use jaw liners or soft materials to prevent damage.
• Ensure sufficient projection from the chuck to prevent deflection under cutting forces.
• Select jaw shape to match the workpiece for ideal clamping contact.

Machining Applications for 6 Jaw Chucks

6 jaw power chucks excel in the following typical machining applications:

• Precision turning - Excellent concentricity allows precision OD and ID turning and boring.
• Milling - Secure rigid clamping enables aggressive milling with minimal runout.
• Drilling - Precise centered holes can be drilled. Chuck absorbs cutting forces.
• Off-center turning - Easily adjusted for turning lobes, cams, eccentric parts and more.
• Multi-sided parts - Hexagons, squares and polygons are clamped evenly and securely.

Popular 6 Jaw Power Chuck Brands

Some of the major manufacturers of 6 jaw power chucks include:

• Kitagawa - High precision Japanese chucks covering a wide range.
• Röhm - German made self-centering hydraulic and pneumatic chucks.
• Bison - US brand offering rugged hydraulic 6 jaw chucks.
• PAM - Italian chucks designed for high performance requirements.
• OML - Czech Republic chucks with excellent accuracy.

Conclusion

With their independent jaw adjustment and high clamping forces, 6 jaw power chucks provide secure, accurate and rigid workholding for demanding machining applications. Their versatility in holding round, odd-shaped and multi-sided workpieces makes them a valuable addition to any machine shop. Choosing the right design and features allows 6 jaw chucks to improve productivity and part quality.

FAQs

What is the benefit of 6 jaws vs 3 jaws?

A 6 jaw chuck has greater clamping accuracy and rigidity due to each jaw moving independently. This allows precise centering and gripping of the workpiece. 3 jaw scroll chucks can sometimes struggle to center workpieces accurately.

When should I use integral vs removable top jaws?

Integral jaws machined into the chuck body provide maximum rigidity for heavy duty milling. Removable top jaws allow quick changeover between different jaw shapes and are good for general turning work.

How do I select the right chuck size?

Consider the largest diameter workpiece that will be machined. Add some extra capacity and choose the chuck size that provides sufficient swing clearance beyond this maximum workpiece size.

What causes excessive runout in a 6 jaw chuck?

Potential causes include: uneven jaw clamping force, chips or debris between jaws, poor mounting interface, worn chuck or jaw damage. Always clean the chuck and workpiece before use.

When should I use a hydraulic vs pneumatic chuck?

Hydraulic chucks offer higher clamping force for milling and other demanding tasks. Pneumatic chucks are often adequate for general turning operations and are lower cost and easier to maintain.