Hello everyone,

I spotted an Omega Seamaster De Ville on eBay that has a movement I am questioning. The watch is time only so no day or date function. The trend I have seen is the movement will have 17 jewels if it is time only and it will have 24 jewels if it is date or day date. This watch has a 24 jewel movement but it is time only. It is a 552 movement which I looked up and it appears it is supposed to have 24 jewels but I think that this movement was mean to be paired with a Seamaster De Ville that has the date or day date function. I am including the pictures from the listing.

 

A quick search on google images for "omega 552 movement" yields countless photos showing 552's with 24 jewels.

 

552 is a no date movement, the 562 will have date and both 24 jewels.

 

No relationship between jewel count and date feature.

There are 17 and 24-jewel versions either way.

 

17 jewel versions were usually intended for the US market. America imposed a larger tariff on watches over 17 jewels - the more jewels, the higher the tax.

 

I learned quite a bit from all these posts and have cured some of my ignorance. I know more jewels doesn't necessarily mean a better movement but in this case did the 24 jewel movement have all functional jewels or were some useless jewels?

 

The extra jewels are cap jewels and other less critical jewels. They perform a function, but don't necessarily reduce friction all that much.

 

Thank you for the information. I once read that the maximum number of jewels that a time only wristwatch can use is 28 but Patek Philippe found that some jewels meant to reduce friction actually made the watch less accurate. I don't know if that is entirely true but if it is good enough for Patek Philippe then it is good enough for me.

 

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

 

I don't know if this is the right place to ask this question. Today synthetic jewels are used in movements. How long has this been the case? Were jewels used in watch movements before synthetic jewels could be made? Would that make an older jewelled watch more expensive because REAL jewels were used? Just a thought.

 

Synthetic jewels were invented in 1892, and became public knowledge in 1902, but you'll see details in the first link below.

Information and history on jewels in a watch:

http://www.watchtalkforums.info/forums/thread14382.html

http://www.watchtalkforums.info/forums/thread14627.html


The whole series:

http://www.watchtalkforums.info/forums/thread22496.html

 

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

 

Very cool to get to see this Al, thanks for posting all of this!

 

Thanks for the links. Makes for interesting reading. It looks to me that ULACKFOCUS is everywhere (the Shadow (Ulackfocus) knows!!)