3 x 6 x 12.25 Hirobo HI2521134 Shaft Collar for RC Helicopters  [HI2521134]

Shaft Stop and Alignment Sleeve

This collar is a general replacement component within the Hirobo helicopter parts catalogue. The model HI2521134 specifies the 3 x 6 x 12.25 size where precise axial location and concentric alignment of rotating elements are needed.

As an axial stop and alignment sleeve, the collar is installed inside transmission or rotor assemblies to control endplay and maintain concentricity. During replacement, verify mating measurements, clean both shaft and bore contact areas, slip the collar into place, and lock it with the original retaining system. After installation, recheck runout and axial play as part of tuning to ensure smooth, predictable performance.