Skip to content
The Encyclopedia of Horology

Glossary · Complication

Chronograph

A watch mechanism adding start, stop and reset timing functions to ordinary timekeeping.

Explanation

A chronograph adds an independently controlled timing train to a watch that continues to keep ordinary time. The key parts to distinguish are the coupling system, the control system and the reset system. A horizontal clutch, vertical clutch, column wheel, cam, heart cam, hammer and recorder each describe a different job; using one term for the whole mechanism hides important evidence.

Photographs must identify the exact example shown. A centre-seconds chronograph, split-seconds chronograph and minute-register chronograph can look similar from the dial side but differ greatly under the bridge and dial. A famous high-grade chronograph photograph should not be used as proof of the mechanism in a simpler watch unless the calibre is actually the same.

Sources & references

  1. de Carle, D., Practical Watch Repairing — chronograph work
  2. Daniels, G., Watchmaking — chronograph construction

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

What to record

  • Record register count, pusher arrangement and reset behaviour separately.
  • Confirm column wheel or cam only from visible parts or documents.
  • Keep ordinary running condition separate from chronograph function.

Do not repeatedly start, stop or reset an unserviced historic chronograph for demonstration.

In the object catalogue

Catalogued objects whose own source record mentions “Chronograph”. The quoted line shows where; it is the seller’s or museum’s wording, not independent verification.