Is this the Right Movement?

No relationship between jewel count and date feature.

There are 17 and 24-jewel versions either way.

The 7 extra jewels are all in the automatic winding system - none of them are cap jewels, and they are certainly an improvement over the bushings used in the 17 jewel version from a wear standpoint.

Cheers, Al

There is no truth in that story...the number of jewels in a watch (a modern watch anyway) is related to the design and complexity of the movement. A jewel must be functional to be counted.

Most jewels act as bearing surfaces, and the alternative to having a jewel is either a simple hole in the brass movement plate, or a bushing - both of these wear more easily than synthetic ruby does. It's very rare to have to replace a plate jewel for wear, where bushings are far more commonly replaced.

Here is an example - my GO, uses 48 jewels, so 20 more than this supposed "limit":



There was a time when companies added jewels just to make it look good (some watches had over 100, with the vast majority being completely non-functional. But very generally speaking, and all else being equal, more jewels is "better" as they reduce friction, and provide a longer life than a simple bushing does.

So in the example of the 550 series Omegas, the 24 jewel movements were better than the 17, as the bushing in the automatic bridges wear more easily than the jewels do. For older pocket watches, the higher the grade and accuracy, the more jewels the watch typically has. Today a manual wind with 17 jewels is considered to be fully jeweled.

Hope this helps.

Cheers, Al

Interesting reading. Apparently most of the earliest imports both to the US and Australia only had 2 jewels.

Real rubies were used before synthetics, but these are typically not "valuable" jewels in terms of being gemstone quality. In fact due to the inclusions that the real rubies tend to have, they are often less desirable for use in watches than synthetic.

Of course we say rubies, but the material is corundum, which is clear. The type of impurities determine the final colour, and I have seen jewels of various colours in watches that I have serviced. Mostly red, but often clear, and sometimes even fairly deep blue, as in this Zenith pocket watch:



And here is a shot taken at the Watchmaking Museum in Glashütte in Germany, which is the center of German watchmaking - as you can see the jewels that were being made in the school there are of various colours:



Ruby/corundum isn't the only gem material used for jewels. Some high grade American pocket watches used diamond cap jewels on the balance staff, and more recently the German company Sinn tried to use diamonds for the pallet jewels (Diapal) but that effort didn't work out. Although they still have watches using technology they call Diapal, the pallet fork jewels are typical corundum (ruby), and the escape wheel has been treated with a coating, so the escapement requires no lubrication. Oh, and no "co-axial" needed for that either. 😉

Cheers, Al