2.6 x 4 x 12S Shaft Collar for RC Helicopter Shafts - Hirobo HI2521080  [HI2521080]

This Hirobo HI2521080 collar is produced for use as a small shaft stop in helicopter maintenance and repairs. The 2.6 x 4 x 12S designation identifies the nominal size used to match collars to shaft diameters and linkages.

It acts as a retention and positioning element, limiting axial travel and keeping assemblies aligned during operation and handling. Install it where a discrete axial locator is required within rotorheads or transmission clusters.

To fit, slide the collar onto the shaft at the intended location, align with mating parts, and secure following your model's assembly practice. Inspect the installation then run a slow trial to make sure rotation is free and there is no binding.

For adjustments and tuning, the collar permits small corrections to shaft endplay and alignment. Reposition or replace collars to fine-tune gearbox spacing and reduce unwanted lateral movement without changing major components.