Component record · Dial & hands
Dial Washer
VerifiedA thin washer, typically of brass or fibre, fitted over the centre arbor or cannon pinion post beneath the motion works to take up end-shake and maintain correct spacing.
What it does
Provides a controlled bearing and spacing surface for the motion-works wheels, taking up small clearances so that the cannon pinion, minute wheel and hour wheel run smoothly without excessive play or binding.
How it works
Because the motion works stack several thin wheels concentrically above one another on the dial side, small washers are used to set the correct end-shake (axial play) between them, preventing wheels from binding against each other or against the plate while still allowing free rotation.
A dial washer is a small, easily lost part during disassembly, and its omission or substitution with an incorrect thickness during reassembly is a common source of a motion works that either binds or exhibits excessive end-shake and consequent poor hand-setting feel.
Evolution
A simple, largely unchanged solution to end-shake control in motion works throughout the history of separate hand-setting mechanisms.
Known variations
- Brass dial washer
- Fibre or paper dial washer
- Sprung dial washer providing light preload in some designs
Identification for collectors
- A thin, easily overlooked disc found loose within the motion works stack during disassembly, whose correct replacement is needed for proper hand-setting feel
Common failure modes
- Lost or omitted washer during servicing, causing excess end-shake or binding in the motion works
- Worn or crushed washer no longer maintaining correct spacing
Related photographs
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.