In early stem wound and set watches the usual Swiss 'positive' set keyless work (in contrast to American or negative set) incorporates this detent as part of the mechanism, usually a notch on the yoke, whereas in later watches it is integrated into the cover plate as in this watch. Stem set keyless work needs a detent to hold the crown in the winding or setting position. The setting lever spring was an evolution of the earlier simple cover plate that simply kept all of the parts of the keyless work in place. These are smaller, simpler, and less easy to identify with certainty.
The other two parts shown are the setting lever and the yoke that moves the sliding pinion. 445, or 'set bridge' in American parlance. This cover is called the 'setting lever spring' in Swiss parts lists, with the generic part No. This has an integrated detent spring which holds the setting lever in either the winding or setting position. The most significant part for identification is the largest part, the cover plate. For example, The Bestfit Book includes the diagram shown here of the parts of the keyless work of ETA calibre 715 and Eterna 710. Bestfit 1965 ETA 715 and Eterna 710 The keyless work under the dial that handles stem winding and setting is often said to be the 'fingerprint' of a movement. Manufacturers altered the appearance of their movements by changing the top plates, but the basic layout remained much the same.
In fact, the apparently huge variety of Swiss watches is explained by this phenomenon: once the basic layout in a round movement of the barrel, train wheels, escapement and balance was arrived at, there was little scope, let alone need, to change it. It is often difficult to identify movements from the shape of the top plates or bridges alone.Īlthough some movements such as the IWC calibre 64 leap out to the experienced eye, other are less easy because of similarities between the products of different manufactures, and manufacturers altering bridge shapes for different customers. The idea of this page is to try to identify otherwise unknown movements found in the type of watches that I collect, which are principally Great War era men's wristwatches with 12 or 13 ligne movements. I don't intend to show movements with their makers names on them, because they are already identified. It is a small selection of often unidentified old movements that I have been able to positively identify. com is the online resource for information about the Gallet MultiChron 12 chronograph.Ĭontents This page is not intended to be a comprehensive reference of watch movements, of which there are many thousands.
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