TAIKI 5″ JAW BORING RING (3900-4650)

Taiki 5″ Soft Jaw Boring Ring for Compact CNC Turning

The Taiki 5-inch jaw boring ring is a dedicated setup tool for machining soft jaws on compatible compact CNC lathe chucks. It loads the jaws from their front counterbores, helps compensate for normal jaw lift and leaves the center open for through-boring.

Instead of searching for a suitable disc or machining a temporary preload plug, the operator can use the reusable ring to prepare workpiece-specific jaw profiles for small components, second operations and recurring production jobs.

Its 5-inch size and 2.6 lb shipping weight make it particularly relevant to compact turning centers and compatible subspindle applications where workspace, tool clearance and setup time matter.

Why Use a Dedicated Ring on a 5″ CNC Chuck?

Small CNC components can still require highly controlled workholding. When the gripping diameter is short, thin-walled or already finished, a poorly prepared jaw profile may cause runout, marking or inconsistent seating.

The Taiki ring supports the jaw-boring process by:

• Preloading the chuck mechanism during machining
• Applying balanced pressure across the jaw set
• Helping account for normal jaw lift
• Keeping the jaw center open for the boring tool
• Eliminating the need for an internal preload disc
• Providing a reusable tool for recurring setups

How Do You Bore Soft Jaws Without Using a Plug?

A common method of preloading soft jaws is to clamp a disc or plug inside them. The problem is that the setup piece occupies the same area the boring bar may need to machine.

The Taiki ring engages the jaws from the front. Its central opening remains unobstructed, allowing the operator to machine through the jaw profile when the boring depth and tool geometry require it.

This open-center configuration is useful for:

• Through-bored gripping profiles
• Small parts requiring deeper jaw engagement
• Second-operation jaws with an axial stop
• Clearance behind the primary gripping diameter
• Workpieces that require a longer boring-bar path

Machine the Jaws Under a Representative Load

The mechanical position of the jaws changes slightly as chuck pressure is applied. If the gripping profile is machined without preload, the jaws may move to a different position when the production part is clamped.

The boring ring simulates a loaded condition while the jaws are being machined. For better results, the chuck pressure, jaw position and loading direction should represent the final operation as closely as practical.

This helps create a jaw profile that corresponds more closely to the actual workholding condition instead of the unloaded position of the chuck.

Designed to Compensate for Normal Jaw Lift

Jaw lift is the small tilting or upward movement that may occur at the front of a chuck jaw under load. This movement can affect axial seating, gripping contact and workpiece runout.

The Taiki ring applies preload through the jaw fronts and is designed to account for normal jaw lift during boring.

It cannot repair or compensate for severe mechanical problems such as:

• Worn or damaged master jaws
• Loose chuck guides
• Damaged jaw serrations
• Chips trapped under the top jaws
• Excessive chuck-body or spindle runout
• Incorrectly tightened jaw screws

Balanced Pressure Across the Jaw Set

The adjustable contacts are positioned in the soft-jaw counterbores. When correctly adjusted, they distribute preload across all engaged jaws instead of relying on an improvised component with uncertain contact.

Consistent preload is important when the objective is to bore a common gripping diameter relative to the chuck axis.

Tool-Free Front-Jaw Attachment

No separate mounting tools are required to attach the ring to the jaws. The contacts are located in the jaw counterbores, the ring is adjusted until snug and the chuck is then actuated to establish preload.

This design can reduce non-cutting setup time in workshops that frequently prepare dedicated jaw sets for small production runs.

Ideal for Small-Part CNC Turning

The 5-inch model is designed around compact workholding rather than maximum component size. It can support soft-jaw preparation for suitably sized:

• Small bushings and sleeves
• Precision collars and spacers
• Bearing retainers
• Instrument components
• Small hydraulic and pneumatic parts
• Automation-machine components
• Miniature flanges and adapters
• Parts requiring a controlled second operation

Compact Main-Spindle and Subspindle Setups

Where dimensionally compatible, the ring may be used with a 5-inch three-jaw chuck installed on a compact main spindle or subspindle.

For subspindle work, verify:

• The actual chuck diameter and jaw type
• The soft-jaw counterbore dimensions
• The required jaw position
• Machine-enclosure and turret clearance
• Part-transfer gripping direction
• The preload direction required by the second operation

Not every subspindle identified as “5-inch class” uses the same jaw geometry.

Second-Operation Soft Jaws

A finished or semi-finished component often needs to be reversed for OP20. Machined soft jaws can support the existing diameter and provide a locating step for controlling axial position.

The Taiki ring helps prepare these jaws while keeping the center open for the boring bar. This is useful when the gripping profile must extend through most or all of the jaw width.

Reduce Setup Time on Short Production Runs

On a small order, soft-jaw preparation can represent a significant percentage of total production time. A dedicated 5-inch ring eliminates the recurring need to locate or manufacture an internal setup disc.

The benefit becomes more noticeable when:

• The machine changes jobs frequently
• Several operators prepare jaw sets
• The same parts return in small batches
• Jaw setups must be documented and reproduced
• Finished components require controlled rechucking

Recommended Setup Procedure

1. Place the CNC lathe in a safe setup condition.
2. Clean the master jaws, serrations, soft jaws and chuck face.
3. Install the jaws in their correct numbered positions.
4. Tighten the jaw screws according to the chuck manufacturer’s procedure.
5. Place the boring ring over the chuck face.
6. Locate each adjustable contact in a soft-jaw counterbore.
7. Adjust the ring until every contact is securely positioned.
8. Actuate the chuck using pressure representative of the production setup.
9. Check boring-bar, ring, turret and machine-enclosure clearance.
10. Bore the required gripping diameter and locating step.
11. Stop the spindle completely before releasing the chuck.
12. Remove the ring, clean the jaws and test the workpiece.
13. Measure runout and seating before starting production.

A maximum spindle speed is not included in the supplied specifications. Use only a safe jaw-machining speed permitted by the machine, chuck, jaw and boring-ring manufacturers.

Match the Final Clamping Direction

The boring process should reproduce the production clamping direction. A ring setup used to preload jaws for external workpiece gripping may not represent the forces required for internal expansion gripping.

Before machining the jaws, confirm:

• Whether the finished part will be gripped externally or internally
• The required chuck actuation direction
• The intended hydraulic pressure
• The final gripping diameter
• The required gripping depth
• The location and depth of any axial stop

Reference Dimensions

The A–G references correspond to the manufacturer’s dimensional drawing. Use the diagram when comparing the ring with the intended chuck and jaw configuration.

Technical Specifications

Will It Fit Your 5″ CNC Chuck?

Check all of the following before ordering:

• The chuck is nominally 5″ in diameter.
• It uses a compatible three-jaw arrangement.
• The soft-jaw counterbores accept the ring contacts.
• The required jaw position falls within the adjustment range.
• The 5.50″ overall ring diameter clears the machine enclosure.
• The boring tool can reach the complete jaw profile.
• The ring clears the turret, chuck body and machine guards.

Choose the Correct Taiki Jaw Boring Ring

Do not select the boring ring only by overall machine size. Match it to the actual chuck diameter, jaw geometry and counterbore arrangement.

Frequently Asked Questions

What boring ring fits a 5″ CNC chuck?

The Taiki 3900-4650 is intended for compatible 5-inch chuck setups. Verify the soft-jaw counterbores, required jaw position and machine clearance before ordering.

Can I use it on a CNC subspindle?

It may be suitable for a compatible 5-inch subspindle chuck. Confirm the chuck model, jaw geometry, turret clearance and final clamping direction.

Can the jaws be bored completely through?

Yes, when the jaw and boring-tool geometry permit it. The front-mounted ring leaves the central machining area open.

Does it include a chuck or jaws?

No. This listing includes the Taiki jaw boring ring only. The chuck, soft jaws, boring bar and workpiece are not included.

Will the ring fix excessive chuck runout?

No. It helps preload the jaws and compensate for normal jaw lift while boring. It cannot repair chuck wear, spindle runout or damaged master jaws.

What is the difference between the 5″ and 6″ models?

The 3900-4650 is sized for a compatible 5-inch chuck. For a 6-inch chuck, use the Taiki 3900-4651 6″ Jaw Boring Ring.

Stop Making a New Jaw-Boring Plug for Every Setup

The Taiki 5-inch ring gives compact CNC workshops a dedicated way to preload soft jaws while preserving full access for the boring tool.

Ready to order but unsure about fit? Send SHOP TOOL USA the chuck brand, model, nominal diameter, photographs of the jaw fronts and counterbore measurements. We can help compare the setup before you purchase.