Split Sleeve vs Split Mandrel: cold working technical comparison
Objective comparison Split Sleeve vs Split Mandrel: precision, productivity, surface quality, operational cost. Use case recommendations.
Comparison table
| Criterion | Split Sleeve | Split Mandrel |
|---|---|---|
| Surface quality | Excellent (no direct contact) | Good (light marks possible) |
| Cycle time | Longer (sleeve insertion) | Faster |
| Consumable | Single-use sleeve | None (reusable mandrel) |
| Accessibility | Good (compact tooling) | Very good |
| Lot traceability | Excellent (sleeve numbering) | Per operator cycle |
| Consumables cost | High (recurring) | Low |
| OEM approval | Airbus, Boeing, Bombardier | Mostly Boeing |
Recommended use cases
When Split Sleeve is preferable
- Titanium and stainless steel holes (enhanced traceability)
- Small batches / prototypes (no dedicated mandrel investment)
- Primary structure repair (critical surface quality)
- Demanding OEM audits on sleeve traceability
When Split Mandrel is preferable
- High-rate series production in aluminium
- Environments where consumables management is constrained
- Repetitive diameters (mandrel investment amortised)
Who supplies the tooling in Europe?
The global cold expansion market has only two players, both based in Seattle: FTI (Fatigue Technology), inventor of Split Sleeve Cold Expansion™ and ForceMate® expanded bushings, and WCI (West Coast Industries), the long-standing reference for split mandrel. In Europe, WCI products are distributed exclusively by Capaero; Kronos Engineering is an official FTI partner and supplies FTI tooling (mandrels, split sleeves, gauges, pullers, complete kits).
The practical consequence: choosing the technology also locks in the consumables supply chain for the entire life of the programme. It is a criterion to settle at qualification stage, just like the material or the production rate.
Kronos Engineering's position
We operate both technologies according to customer needs — with no commercial preference. Our recommendation follows an analysis of your case (material, diameter, production rate, tooling budget). Request a free comparative study.