Hirobo HI2521016 Collar (A) 4 x 7 x 1.5 mm for Small RC Shafts  [HI2521016]

RC Shaft Collar Overview

The Hirobo ball bearing collar provides controlled axial location for small bearings in model mechanisms. The 4 x 7 x 1.5 size indicates inner diameter, outer diameter and thickness, and this collar is classed as type "A" for accurate placement rather than for carrying heavy loads.

The collar functions as a spacer and locator that butts up against a bearing face or housing to limit endplay. Fitting is simple: slide the collar onto the shaft against the bearing or place it in the designated recess, then secure the assembly with the model's fasteners. Double-check that the collar's ID and OD correspond to the mating bearing and shaft before finalising the fit.

Tweaking the collar position by small amounts can influence gear mesh and axial clearance in compact gearboxes and rotor assemblies. Fit the collar to remove shaft slop and to achieve consistent spacing when rebuilding micro drivetrains or rotorheads.