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The Encyclopedia of Horology

Component record · Keyless work

Castle (Clutch) Wheel

Partially verified

A sliding wheel with toothed faces engaging winding or setting.

What it does

Couples the stem either to the winding train or to the setting wheels.

How it works

Pulling the crown moves the yoke, sliding the castle wheel out of engagement with the winding pinion and into mesh with the setting wheel.

Its castellated faces allow engagement in either direction of rotation.

Evolution

A standard element of nearly all twentieth-century keyless work.

Known variations

  • Castle wheel with yoke
  • Rocking-bar alternatives

Identification for collectors

  • Recognised by its two toothed faces and central groove for the yoke.

Common failure modes

  • Rounded teeth causing slipping
  • Wear on the yoke groove

Diagram

crownsliding clutchsetting wheelswinding pinion and ratchet
Schematic: keyless winding and hand setting. 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.