RC Helicopter EX Washer 4mm Hirobo HI2506040 - Thin Alignment Shim  [HI2506040]

Thin spacer for precise rotorhead setup

This 4mm EX washer is an RC-scale thin spacer intended to provide precise spacing and alignment in helicopter assemblies. It removes slack between mating parts, aids in lining up linkage pivots, and sets fine clearances at bearing seats within the rotorhead region.

Fitting is straightforward: slide the washer onto a 4mm shaft or over a 4mm bolt shank where minimal spacing is required. You may stack washers to obtain incremental thickness and then check for free rotation. Use small tools and avoid forcing oversized parts through the washer to protect both the washer and surrounding bearings.

During tuning, the washer is a handy tool for micro-adjustments instead of replacing spacers; it lets you refine linkage geometry and cut down endplay without major changes.