HIROBO HI2521101 Precision 3 x 4 x 3.5mm Collar for RC Linkages  [HI2521101]

Precision spacer for RC linkages

This RC-scale collar functions as a compact spacer for helicopter linkages and other tiny mechanisms where precise clearance is needed. It is supplied as an aftermarket replacement-style accessory for model servicing and setup, not intended for use on full-size equipment. The collar keeps pins centred and maintains repeatable clearance between shafts and link ends.

Material and fit: made from nylon, the collar delivers low friction and reasonable wear resistance for light-duty link interfaces such as swash and rotor head connections. The material reduces the chance of binding when paired with metal pins and helps preserve consistent movement under small loads.

Installation notes: wipe shafts and pins clean before fitting, slide the collar into place until it seats, then confirm there is no binding. If excess play remains, double-check pin diameter and seating surfaces rather than forcing a different size. Treat the part as a passive spacer and ensure surrounding fasteners are torqued to the assembly requirements.

Tuning role: fit the collar to make small incremental changes to control link spacing, which can reduce slop and equalise lever lengths across matched link sets. It performs best when used with careful link angle and throw adjustments.