SKF PHFFX51-30X55 keyless shaft bushing / locking assembly. Frictional shaft-to-hub coupling that transmits torque without a key or splined joint, by radial-elastic clamping between the shaft and hub. Executed as a double-taper collet (self-centring), a single-taper Ringfeder-style assembly, or a stepped-piston hydraulic clamp. Removed and re-installed non-destructively; excellent choice for high-precision or high-torque locations where a keyway would fatigue the shaft.
| Type | Keyless shaft bushing / locking assembly |
| Designation | SKF PHFFX51-30X55 |
| HS code | 8483.60 |
| Bore diameter | 30 mm |
| Outside diameter | 55 mm |
| Width, total | 34 mm |
| Element width | 17 mm |
| Bushing number | FX51 |
| Category | Keyless bushings |
| Number of clamp screws | 6 |
| Product net weight | 0.4 kg |
| eClass code | 23-05-19-01 |
| UNSPSC code | 31171605 |
| Material | As declared by SKF designation suffix |
| Temperature range | Per SKF product data |
| Primary standard | SKF designation convention |
| MOQ | 1 |
Interchange with peer OEM equivalents on identical boundary plan and execution — confirm cage, clearance, sealing and precision-class suffix before substitution.