Copper Washer Set HA194 for OS4C-120 Engines by Hatroi  [HA194]

Precision copper washers for OS4C-120

The Hatroi HA194 copper washers are designed as RC-scale replacement parts for the OS4C-120 listed in the product title. Constructed from copper, these washers give a conforming sealing face and provide small spacing corrections where metal components require a softer mating surface to preserve contact and limit loosening under vibration.

In use these washers act as crush or spacer pieces on threaded connections and mating surfaces in RC engine assemblies and related fittings. Copper's ductility enables the washer to compress under torque, improving the seal and compensating for tiny surface defects without cracking.

Fitment tips: clean contacting faces before installation, discard washers showing excessive deformation or work-hardening, and use the correct torque for the fastener to prevent over-compression. For tuning, HA194 washers can be layered to change clearances, but proceed gradually and test on the bench first.