Rubber Flex Expanding Collet for Blind Holes
Used when the workpiece bore does not pass through and the part must be located from the inside diameter.
Internal bore clamping for rings, sleeves, gears and parts located from the inside diameter.
Expanding Mandrels
KORRETTO expanding mandrels and internal expansion rubber collet systems clamp the workpiece from the bore instead of the outside diameter. They are used for sleeves, rings, gears, bearing seats, flange bores and parts where the internal diameter is the main locating reference. This category includes blind-hole expanding rubber collets, through-hole expanding rubber collets, through-hole expanding collet chuck units and related internal expansion solutions.
Through-Hole Rubber Flex Expanding Collet
Suitable for bore-based location where the expanding collet can pass or expand through the workpiece.
Through-Hole Rubber Flex Expanding Collet Chuck
Provides the chuck body or mounting unit needed for through-hole expanding rubber collet applications.
Blind-Hole Expanding Rubber Collet Chuck
Internal expansion rubber-flex chuck assembly for blind-hole and semi-through-hole workpieces where outside clamping must remain clear.
How to Select an Expanding Mandrel
- Confirm the bore type
Check whether the workpiece has a through bore, blind hole, stepped bore or limited effective bore depth. - Start from the locating reference
Expanding mandrels are suitable when the inside diameter is the functional reference or when outside clamping may damage the part. - Check bore tolerance and contact length
The bore diameter, tolerance, contact length and surface condition affect the selection of mandrel or expanding collet. - Review wall thickness and cutting load
Thin-wall parts may need flexible internal expansion. Heavy cutting may require a more rigid mandrel or support structure. - Compare with external clamping
If the outside diameter is the better locating surface, rubber flex collets, collet chucks or jaw chucks may be more suitable.
Quick Selection Table
| Requirement | Start with |
|---|---|
| Blind-hole internal clamping | Rubber Flex Expanding Collet for Blind Holes |
| Through-bore internal clamping | Through-Hole Rubber Flex Expanding Collet |
| Complete machine-side internal expansion unit | Through-Hole Rubber Flex Expanding Collet Chuck |
| Bore as the main functional reference | Expanding Mandrel / Expansion Sleeve Mandrel |
| Thin-wall bore-sensitive part | Rubber expanding collet system |
| External surface should not be marked | Internal expanding mandrel |
FAQ
What is an expanding mandrel used for?
An expanding mandrel is used to locate and clamp a workpiece from the internal bore. It is common for sleeves, rings, gears, bushings and parts where the bore is the reference surface.
When should I choose internal expansion instead of outside clamping?
Choose internal expansion when the bore is the functional reference, when the outside surface must not be marked, or when outside clamping does not provide reliable location.
Can one expanding mandrel handle blind holes and through holes?
Not usually. Blind-hole and through-hole workpieces require different structures and contact conditions. The bore drawing should be reviewed first.
What is the difference between an expanding mandrel and a rubber expanding collet?
A rigid expanding mandrel often uses a metal expansion structure. A rubber expanding collet uses segmented metal with rubber connection for more flexible bore contact.
What information is needed for selection?
Provide the bore diameter, tolerance, depth, through-hole or blind-hole condition, workpiece material, wall thickness, locating face, machine interface and machining process.
Are expanding mandrels suitable for thin-wall parts?
They can be suitable, but force, contact length and wall thickness must be checked. Rubber expanding collets may help distribute contact more gently.