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The Encyclopedia of Horology

Component record · Escapement

Dial-Side Jewel

Partially verified

A jewel bearing fitted on the dial side of the main plate.

What it does

Supports a pivot from the dial side, often at the escape or fourth wheel.

How it works

Jewelling both ends of fast-running arbors reduces wear where loads are highest.

Evolution

Counted in a movement's jewel total, which is why jewel counts must be read by function.

Known variations

  • Pressed dial-side jewel
  • Screwed setting

Identification for collectors

  • Only visible with the dial removed, so jewel counts should not be judged from the back alone.

Common failure modes

  • Cracking
  • Dry running from oil migration

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.