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The Encyclopedia of Horology

Cincinnati, OH, United States · 1847 – 1911

Dietrich Gruen

Partially verified

Watchmaking

Life & work

Founded the Gruen Watch Company; German-born American horologist.

Training, contributions & innovations

  • Invented the safety pinion for watches

Inventions & patents

  • Patent for the safety pinion (1874)

Signatures & markings on surviving work

  • D. Gruen & Sons

Collecting significance

Authenticity depends on signatures and movement quality. For 19th-century makers, serial numbers often allow for precise dating. For modern independents, documentation from the maker is key.

Diagram

12345let downstripcleanoilregulateorder of work; never skip letting down the mainspring
Schematic: order of work at the bench. An outline schematic drawn to show the arrangement of the parts discussed here. It is not a dimensioned working drawing and does not depict a particular maker's calibre.

Sources & references

  1. Britten, F. J., Old Clocks and Watches and Their Makers
  2. Loomes, B., The Early Clockmakers of Great Britain
  3. Ehrhardt, R., American Pocket Watch Identification and Price Guide
  4. Museum catalogue records

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