Dating mappin and webb silver plate marks

If you click on the pictures a bigger one should pop up in a new window.I don't mind you using these for your own personal research, but if you want to use them elsewhere such as on an internet forum, a web site, or in a publication, please read my copyright notice first and include attribution.It is often difficult to identify movements from the shape of the top plates or bridges alone.Although 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.Movements from the 1920s or earlier, with cover plates that don't have integrated detent springs, don't generally appear in the Bestfit or similar books and are therefore harder to identify. The first step in identifying a movement is to determine its size in lignes.The cover plates are often just as unique, it's just that by the time the Bestfit books were introduced, watches with such movements were considered "obsolete". The image here from the "Official Catalogue of Swiss Watch Repair Parts" issued by the Watchmakers of Switzerland in 1948 shows how movements are measured for diameter D and height H.

Preeten sex

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.Note that the setting lever screw is an exception to the rule about screw placement, it can be in different places in stem set and pin set varieties of the same movement, or absent altogether if the keyless work is negative set.The shape of the cocks and bridges is more of an aesthetic consideration; so long as all the pivot holes and screw holes are in the same places, then bridges of very different shapes can be freely interchanged.The movements are definitively identified as Eterna by their keyless work, but their top plates are different from those shown in Jobin.

The really definitive "fingerprint" of a movement is the keyless work, which is why materials parts suppliers such as Bestfit and Schwartchild often show only the components of the keyless work in their movement identifications.

If you have any knowledge about this, please let me know.