Hirobo HI2521067 4 x 5 x 6.5 mm Shaft Collar for RC Helicopters  [HI2521067]

Compact shaft collar 4 x 5 x 6.5 overview

This collar is produced for RC-scale shafts and carries the 4 x 5 x 6.5 marking to denote its nominal dimensions. It serves as a spacer and axial stop on small shafts where consistent blade position and spacing affect rotor balance and control link geometry.

Installation is straightforward: slide the collar to the chosen position on the shaft and secure it according to the hub and shaft method in use. The stated size is intended for small rotor interfaces; verify the physical fit before final assembly to avoid contact with bearings or adjacent components.

During setup and servicing, the collar is a handy item for adjusting blade tracking and preserving head geometry after part changes. Keep extras for routine rebuilds and iterative setup tests where millimetre adjustments change rotor behaviour.