3 x 5 x 5.1F Shaft Collar Hirobo HI2521107 for RC Helicopter Shafts  [HI2521107]

Shaft positioning collar for micro models

The Hirobo HI2521107 collar is supplied as a small shaft collar for RC helicopter use, with the 3 x 5 x 5.1F dimension serving as the size reference for compatibility with shafts and adjacent parts. Its role is to position and retain components along a shaft or act as a spacer between assemblies.

Prior to fitting, confirm that your shaft and assembly are compatible with a 3 x 5 x 5.1F collar. Slide the collar into position and secure it using the model's appropriate retention method. Material data was not provided in the source, so check the seller listing or inspect the item on arrival if material properties are a concern.

Use cases include setting endplay, aligning small gear trains and stabilising linkage elements where precise spacing is required. Label spare collars clearly to prevent mixing sizes during maintenance tasks.