Durowe age determination using various methods
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A brief overview of the history of DUROWE
Ludwig Hummel founded the German Clock Raw Works (DuRoWe) in Pforzheim on October 23, 1933 .
Hummel intended to supply his company Laco , as well as other watch manufacturers in Pforzheim and beyond, with watch movements . Within a few years, thanks to a favorable price-performance ratio, monthly production increased to approximately 30,000 movements. During World War II, the factory in Pforzheim was severely damaged. Immediately after the war, production resumed in the premises of the Wolff metal goods factory, which was already owned by Hummel at that time. The factory building, destroyed in World War II, was rebuilt in 1949 .
On February 1, 1959, Ludwig Hummel sold his shares in Lacher & Co. AG and Durowe to the US Time Corporation . Six years later, on September 1, 1965, Ébauches SA acquired the Durowe brand. The logo changed to INT (International German). Watch movements (DuRoWe). Besides the mechanical movements, only one quartz movement was produced: INT 301.001 as a replacement movement for the mechanical 5½''' ladies' watch movement. A special product is the wristwatch with a parking meter that DuRoWe launched.
This watch was very successful and was also used by Swiss brands. It came in both hand-wound and automatic versions. Calibers 391-4 and 471-4 were used for the hand-wound version, and caliber 7524 for the automatic. The watch was called Minstop (Minute Stop) and was used by many brands such as Vulcain , Buren , Para , Arctos , Perrier, Paul Garnier , Stowa , LIP , Exquisit , Zentra Wille Frères , etc. The automatic version was less common; one of the brands that used it was Seca .
| Period | Event / Development |
|---|---|
| 1933 | Lacher & Co. (Laco) founded Deutsche Uhren-Rohwerke GmbH in Pforzheim. The goal: to produce their own movements for German watches instead of Swiss imports. |
| 1930s–1945 | Production of purely mechanical hand-wound movements, including calibers 410–420 ("Treffpunkt Wehrmachtsuhren"). |
| 1945–1955 | Reconstruction after the war, successful caliber 410/412 series. |
| 1955–1965 | Technical and design maturity: automatic movements (Duromat), shock protection, date, 11xx/25xx series. |
| from 1975 | Integration into Timex Group, production discontinued (end of 1979). |
Typical characteristics of different eras
| design | Dating |
|---|---|
| 15 rubies, small seconds | 1930s–1940s |
| 17 jewels, shock protection, central second hand | 1950s |
| Automatic transmission with rotor “Duromat” | 1955–1960s |
| Slim automatic movement, date | 1965–1975 |
| Work signature | Caliber type | Description | Construction period |
|---|---|---|---|
| “DUROWE 410” | manual winding | 15 rubies, small seconds | 1948 – 1952 |
| “DUROWE 422” | manual winding | centered second hand, Incabloc | 1952 – 1956 |
| “DUROWE 425” | manual winding | flat, dress caliber 17 rubies | 1954 – 1958 |
| “DUROWE 451” | manual winding | new circuit board geometry and shock protection | 1958 – 1965 |
| “DUROWE 2512 (Duromat)” | Automatic | Rotor, 25 rubies | 1956 – 1962 |
| “DUROWE 7425” | Automatic + Date | Flatwork, Incabloc / 17 rubies |
Dating by caliber groups
The DUROWE caliber designation is almost always engraved on the movement plate (e.g. “Durowe 410” or “Durowe 7425”).
This designation can be used to determine the year of manufacture or the era :
| Caliber group | Origin / Production | Typical characteristics | Years of construction (approx.) |
|---|---|---|---|
| Durowe 40x | First raw movements (for military / wristwatches) | small seconds, 15 rubies | 1933 – 1940 |
| Durowe 410 / 412 / 422 | Standard manual winding after WWII | Central seconds stop (not always), robust, 15–17 jewels | 1946 – 1955 |
| Durowe 425 – 430 | refined post-war works | "Incabloc" shock protection | 1953 – 1958 |
| Durowe 441 / 444 / 446 | flatter works, dress-style | small seconds, anchor escapement | 1957 – 1963 |
| Durowe 451 – 455 | mid-generation, Dugena and others use | 17 stones, centered second | 1958 – 1965 |
| Durowe 25xx (series) | fully automated “Duromat” factories | Rotor with ball bearings, 25 rubies | 1955 – 1965 |
| Durowe 70xx / 74xx | late automatic / date | flat, 17-25 rubies, “German Cal. Ref.” |
