4 x 21 Needle Pin for Hirobo Helicopter General Parts - HI2509013  [HI2509013]

Small pin for control link pivots

This Hirobo HI2509013 needle pin serves as a compact replacement for general helicopter assemblies. The listing names it as a 4 x 21 needle pin within Hirobo helicopter general parts and it functions as a basic fastener in tight linkage and pivot locations.

Used in service, the pin helps reduce axial play at rotor link joints and small control pivots, improving control consistency. During routine checks verify the pin sits correctly and that surrounding bores are not worn or elongated; replace the pin if you detect any distortion.

Fitting is commonly a press-fit into a locating bore or held by the model's retainers, with the pin acting as a locating and pivot element rather than a threaded fastener. Allow a small clearance to prevent binding while keeping slop to a minimum.