Dating gruen watches
The building, which still exists, was designed to look like a medieval guild hall.In about 1922, the company built the Precision Factory in Biel/Bienne, Switzerland.One of the most important and prestigious American watch manufacturers was the Gruen Watch Company, founded by a brilliant father-and-son team of horologists, Dietrich and Fred Gruen.Among the first companies to sell wristwatches, the Gruens split their manufacturing between two continents, exporting American technology to Germany and Switzerland, and bringing German and Swiss traditions of craftsmanship to America.To graduate, Fred was given bars of metal from which he had to build working watch movements, designing and manufacturing all the parts.
This will give a good idea of the manufacture date.They designed and manufactured many of their own movements, some of which had interesting complications, in facilities in Biel, Switzerland called the “Precision Factory” (which are now owned by Rolex, and apparently used as admin facilities).That said they were a US based company with headquarters in Columbus, Ohio, where they received the movements, and assembled them into American made cases.I am slowly adding serial number tables to this site. With the exception of BULOVA, the numbers on the inside and outside of the CASE ITSELF are ONLY for identification purposes - they mean nothing.Serial number records are available for many of the old pocket watch companies like AM Waltham, Elgin, South Bend etc. The number you need is the serial number stamped on the MOVEMENT (i.e the inner workings).
Their Ohio facilities were also a thing to behold, with architecture that gave it a fairy tale quality.