How does Shrink Fit Holders work?

Shrink fit toolholding is a straightforward yet powerful technology. Each Shrinker tool holder is made with an internal diameter slightly smaller than the cutting tool’s shank. When heated with an induction unit, the tool holder’s end expands, allowing the cutting tool to slip in easily. As it cools, the tool holder contracts and tightly grips the tool 360° around its shank with uniform pressure.

Removing the tool is just as simple: reverse the process. Tool changes happen in seconds, making it easy to boost productivity by cutting down on tool change downtime.

Superior Concentricity

With shrink fit tooling, you get a guaranteed TIR (Total Indicator Reading) of .0002” or better once the tool is fully shrunk in place. This level of accuracy ensures the cutting tool spins true, minimizing runout and enhancing precision.

Superior Balance

Shrink fit tool holders are designed for high-speed operation. Each tool is dynamically balanced to G2.5 at 20,000 RPM, and special orders can meet G1.0 at 30,000 RPM. No set screws means the holder remains balanced—only the cutting tool itself can affect overall balance. The result? Smooth, stable cutting that improves finishes and allows for higher speeds and feed rates.

Superior Rigidity

Shrink fit chucks typically exert up to 10,000 lbs. of clamping force on the tool shank—more than five times the grip offered by collet or milling chucks. The tool is gripped along the entire length of the bore, delivering near “integral shank” rigidity while offering the flexibility to interchange tools.

Superior Tool Life

By combining a powerful grip, high accuracy, and excellent balance, shrink fit toolholders can extend cutting tool life by 100% or more. The even chip load distribution reduces strain on the cutting edges, allowing you to push tooling harder and still maintain performance.

Superior High-Speed Operation

In extremely high-speed applications, centrifugal force can reduce clamping strength in many standard toolholders. Shrink fit solutions maintain a firm grip even under these conditions, making them a top choice for high-speed machining. Superior balance also protects spindle bearings, reducing wear and prolonging machine life.

Superior Operating Parameters

No other system offers such short projection lengths with .0002” or better concentricity. Shrink fit chucks eliminate the need for extra extension—common in other systems—to accommodate mechanical clamps. Because the profile is slim, it’s easier to machine in tight or hard-to-reach areas. You can also preset tools by simply adjusting how deep the shank is inserted into the holder.

Simple Operation

Changing tools in a shrink fit system is quick and convenient:

1. Heat the holder with an induction tool changer.
2. Remove the old tool, insert the new one.
3. Cool the holder (optional chilling speeds this up).

There’s no need to search for wrenches, torque tools, or vise fixtures. The clamping force remains uniform without manual adjustments.

Conclusion

Shrink fit technology offers exceptional accuracy, balance, rigidity, and speed—all while helping to reduce costs and downtime. These advantages include:

• Best possible TIR (.0002" or better)
• Superb balance for higher speeds and better finishes
• Powerful gripping force for consistent performance
• Extended tool and spindle life
• Slim profile for tighter spaces
• Custom designs and short gauge lengths available
• Preset capability to match the required tool length
• Fewer accessories (no wrenches, collets, or set screws)
• Lower overall costs from reduced tool change time and maintenance

For critical high-speed or precision cutting applications, shrink fit holders deliver unmatched performance and reliability.