Hirobo HI2521016 Ball Bearing Collar (A) 4 x 7 x 1.5 mm  [HI2521016]

Application Notes for Bearing Collars

This Hirobo collar is intended to control axial placement and spacing for small bearings in model assemblies. The size 4 x 7 x 1.5 defines inner diameter, outer diameter and thickness so the collar interfaces correctly with bearing and shaft, and it is designated as type "A" for precise positioning rather than heavy duty support.

The collar acts as a spacer that locates against a bearing face or housing to limit endplay. To install, slide the collar into position on the shaft against the bearing or into its recess and secure the surrounding hardware as your assembly requires. Always confirm that the collar dimensions match the mating bearing and shaft prior to final assembly.

When tuning or maintaining small gearboxes and rotorheads, subtle changes in collar placement can affect gear engagement and axial clearance. Use the collar to remove excess shaft movement and to reproduce consistent spacing when rebuilding micro drivetrains or rotor assemblies.