Component record · Keyless work
Keyless Works Cover Plate
VerifiedA shaped plate, usually held by one or two screws, fitted over the keyless works on the dial side to retain and protect the clutch wheel, yoke, setting lever and associated components.
What it does
Holds the individual keyless-works components captive in their correct positions and protects them from dust and interference, while permitting the assembly to be removed as a group during servicing.
How it works
Rather than each keyless-works component being individually pinned or screwed in isolation, the cover plate (sometimes called a keyless or setting-mechanism cover) is shaped with cut-outs and bearing points that hold the clutch wheel, yoke and setting lever correctly located once the plate is screwed down over them.
Removing the cover plate's one or two retaining screws exposes the whole keyless works for cleaning, lubrication or repair, making it a key step in most full movement services.
Because it also acts as a dust and lint barrier for the winding and setting mechanism, a missing or ill-fitting cover plate can allow debris to enter the keyless works, contributing to a stiff or gritty-feeling crown action.
Evolution
A standard, largely unchanged fitting once keyless works became standard practice, with variation mainly in exact shape between different keyless-works layouts and calibres.
Known variations
- Single-screw keyless cover plate
- Two-screw or multi-point cover plate
- Cover plate incorporating an oiling sink or reservoir feature in some designs
Identification for collectors
- The shaped plate visible over the keyless works when the dial and dial-side motion works are removed, distinguishable from the motion-works dial washers and wheels beneath it
Common failure modes
- Bent or distorted plate no longer holding components in correct position
- Missing or wrong-length screws allowing the plate to sit proud and bind against the dial
- Wear at the plate's bearing points contributing to sloppy keyless-works action
Related photographs
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No confidently matched photograph of this subject has been found yet. These photographs show a closely related record, and are not examples of the type described on this page.
Sources & references
- de Carle, D., Practical Watch Repairing
Where sources disagree, the disagreement is stated rather than resolved silently.