Hirobo HI2521049 Collar 5 x 8 x 1.5mm shaft collar  [HI2521049]

Helicopter Collar 5 x 8 x 1.5mm

This compact shaft collar is an RC-scale accessory intended for use in helicopter assemblies and other small-scale rotary components. The part's 5 x 8 x 1.5mm dimension identifies its bore and outer sizing, making it suitable where short axial spacing or a fixed stop on a shaft is required.

Functionally, the collar provides a mechanical stop and repeatable positioning point for shafts and linkages. In assembly it helps maintain consistent stack-up between gears, bearings, spacers, and other rotor head components, supporting predictable play and preload during setup.

Installation is straightforward: slide the collar onto the shaft to the desired location and secure it according to your model's standard practice. When tuning rotorhead geometry or setting bearing preload, use the collar as a reference element, checking axial movement and clearance after final tightening.

Notes for hobby use: confirm the collar bore matches your shaft diameter before installation, inspect mating surfaces for burrs, and re-check alignment after initial test runs. This description refers to RC-scale model applications only.