Hirobo HI2506040 EX washer 4mm – RC helicopter thin spacer  [HI2506040]

EX washer 4mm for rotorhead spacing

This 4mm EX washer is an RC-scale thin spacer intended for precision spacing and alignment in helicopter assemblies. It serves as a simple, low-profile shim to remove play between mating parts, help align linkage pivots, and set small clearances around bearing seats in the rotorhead area.

Installation is straightforward: fit the washer onto a 4mm shaft or over a 4mm bolt shank where a thin spacer is required, stack multiple pcs when incremental thickness is needed, and check for free rotational movement after fitment. Use small hand tools and avoid forcing oversized parts through the washer to keep the part and surrounding bearings intact.

In tuning and setup, this washer is useful for micro-adjustments where a full replacement spacer or packed thread would be excessive; it lets you fine-tune linkage geometry and reduce endplay without changing major components.