Internal expansion rubber-flex clamping head for through-hole workpieces.
Through-Hole Rubber-Flex Expanding Collet
KORRETTO through-hole rubber-flex expanding clamping head is the replaceable internal expansion element used for workpieces with open-through bores. It expands inside the bore to support the workpiece from the inside diameter. This page covers the expanding clamping head body only, not the complete through-hole expanding clamping head chuck assembly.

Product Overview
The through-hole rubber-flex expanding clamping head is selected when the bore is open through the workpiece and internal expansion clamping is required. It is used as a replaceable element within a matched expanding clamping head chuck or mandrel system.
Selection should confirm the expansion range, bore tolerance, maximum length, workpiece material, support length and whether the application requires the collet body only or the complete chuck assembly.
Key Features
| Feature | Description |
|---|---|
| Through-hole internal expansion | Designed for workpieces with open-through bores. |
| Replaceable collet body | Used as the expanding element in a compatible system. |
| Rubber-flex bore contact | Provides distributed inside-diameter support. |
| Separate from chuck assembly | The through-hole expanding collet chuck assembly is a separate page. |
| Suitable for bore-based clamping | Selected from bore diameter, tolerance and support length. |
Typical Applications
- Through-hole workpieces
- Bore-located components
- Internal expansion clamping
- Parts requiring outside-surface machining
- Replacement expanding collet selection
Technical Data for Through-Hole Expanding Clamping Heads
Use the parameter table to check model, expansion range, recommended workpiece tolerance and maximum length.
| Model | Expansion Range (mm) | Recommended Workpiece Tolerance (mm) | Maximum Length (mm) |
|---|---|---|---|
| SB100 | 20–28 | ±0.25 | 22 |
| SB110 | 26–38 | ±0.25 | 26 |
| SB120 | 35–50 | ±0.3 | 30 |
| SB130 | 48–65 | ±0.35 | 36 |
| SB140 | 60–80 | ±0.4 | 40 |
Related Rubber-Flex Pages
FAQ
What is a through-hole rubber-flex expanding collet?
It is a replaceable internal expansion rubber-flex clamping head used for workpieces with open-through bores.
Is this a complete chuck?
No. This page covers the expanding collet body. The complete through-hole expanding chuck assembly is handled separately.
How is this different from the blind-hole version?
This version is for open-through bores. The blind-hole version is for blind-hole or semi-through-hole workpieces.
What should be checked before selection?
Check bore diameter, expansion range, tolerance, maximum length, support length and matching chuck or actuator structure.
Can this be used for outside machining?
Yes. Internal expansion clamping can leave the outside surface available for machining.
What information should I provide?
Provide the workpiece drawing, bore size, tolerance, material, support length, maximum length and whether the complete chuck assembly is required.



