Hirobo HI2521104 3 X 6 X 12.5S Shaft Collar - Helicopter Part  [HI2521104]

Shaft Collar 3 x 6 x 12.5S for RC Helicopter Assemblies

This replacement part carries the Hirobo reference HI2521104 and serves as a compact collar for use on helicopter shafts and linkages. The 3 x 6 x 12.5S marking indicates the nominal dimensions for matching to your model's shafts and housings.

Prior to fitting, examine shafts and bores for damage or contamination, clean as required, then fit the collar and secure it with the retention method native to your model. Check alignment and clearance after installation since small errors can influence rotor and tail behavior in flight.

In workshop practice, collars are used to fix axial position and prevent lateral movement in rotating components. Periodic inspections during maintenance keep rotor heads and tail systems true, aiding consistent control feel and trim stability.