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The Encyclopedia of Horology

Component record · Power

Rotor Ball Bearing

Partially verified

Race of steel balls

What it does

Reduces friction for the automatic rotor

How it works

Evolution

Introduced by Eterna

Known variations

    Identification for collectors

      Common failure modes

      • Noise/Wear

      Diagram

      cap jewel (endstone)bridgeplatepivot running in a hole jewel
      Schematic: jewelled bearing at a pivot. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

      Sources & references

      1. de Carle, D., Practical Watch Repairing
      2. de Carle, D., Watch and Clock Encyclopedia
      3. Daniels, G., Watchmaking

      Where sources disagree, the disagreement is stated rather than resolved silently.