Hirobo HI2521064 Collar 3 x 6 x 5S shaft collar for RC helicopter components  [HI2521064]

Shaft collar for RC helicopters

This Hirobo HI2521064 collar is an RC-scale shaft accessory identified by the 3 x 6 x 5S marking and intended for use in helicopter component assemblies. It functions as a compact axial stop or spacer on rotating shafts, helping to control endplay and maintain component position within tail or main rotor linkages.

In practice, place the collar at the required axial location on the shaft during assembly, verify alignment with adjacent gears or bearings, and secure according to your model's standard fastening method. Because collars serve to stabilise shaft positioning, they are a simple but useful element during trim and mechanical tuning to preserve gear mesh and control link geometry.