Component record · Dial & hands

Dial Washer

Verified

A 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