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The Encyclopedia of Horology

Component record · Power

Fusee Chain

Verified

A miniature articulated chain, similar in principle to a bicycle chain but on a much smaller scale, linking the mainspring barrel to the fusee cone.

What it does

Transmits the mainspring's pull to the fusee while allowing the point of application to move along the cone's length as the spring unwinds.

How it works

The chain is built from tiny flat links and pins riveted together, strong enough to bear the mainspring's pull yet flexible enough to wind evenly into a helical groove only a fraction of a millimetre wide in small watch fusees.

One end is hooked to the barrel, the other to the fusee; as the mainspring unwinds, the chain unwraps from the barrel and wraps onto the fusee (or vice versa depending on winding direction), moving the effective working radius as described under Fusee.

Because the chain is under continuous tension and subject to fatigue, fusee-chain failure is one of the more common serious faults found in old fusee watches, and a broken chain requires specialist replacement or repair rather than simple substitution with off-the-shelf parts.

Evolution

Chain construction and quality improved through the 18th and 19th centuries as watchmaking tooling matured; gut lines, used in cheaper or earlier work, were progressively replaced by chains in finer watches.

Known variations

  • Fine watch-grade chain
  • Coarser clock-grade fusee chain
  • Gut line (non-chain alternative)

Identification for collectors

  • Examine for broken, kinked, or rusted links, particularly near the hooks at either end
  • A seized or jerky-running fusee movement often points to chain or fusee groove wear

Common failure modes

  • Link fatigue and breakage
  • Rust pitting from historical storage in damp conditions
  • Stretching, causing uneven torque transfer

Photographs

Spindeluhr fusee verge watch fabris 02
Spindeluhr fusee verge watch fabris 02 — Sergio Fabris, CC BY-SA 4.0. Wikimedia Commons file page

Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.

Sources & references

  1. Britten, F. J., Old Clocks and Watches and Their Makers

Where sources disagree, the disagreement is stated rather than resolved silently.