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

Compact needle pin for pivots

This Hirobo HI2509013 needle pin is an RC-scale replacement intended for general helicopter assemblies. Listed as a 4 x 21 needle pin within Hirobo helicopter general parts, it acts as a basic mechanical fastener for small linkages and pivot points.

In normal use the pin helps limit axial movement in rotor linkages and control pivots, contributing to steadier control feedback. Check that the pin seats properly and that surrounding holes remain true; replace the pin if visible wear or deformation appears.

Installation is generally a press-fit into a locating bore or retained by the model's existing retainers, with the pin serving as a locating and pivot element rather than a threaded fastener. For best results keep axial clearance low to minimise slop while avoiding any binding.