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1: Impulse jewel (the part of the balance wheel assembly which receives a kick from the escape lever)
2-5: Balance staff pivot bearings (two pairs - in combinations of one pivot jewel (i.e. jewel with a hole to receive the axle (pivot) of the wheel) and one cap jewel (i.e. jewel without a hole outboard of the pivot jewel, to prevent excessive movement of the balance staff), usually shock protected)
6-7: Escape lever pallets (one pair)
8-9: Escape lever pivot bearings (one pair)
10-11: Escape wheel pivot bearings (one pair)
12-13: Fourth wheel pivot bearings (one pair)
14-15: Third wheel pivot bearings (one pair)
16-17: Center wheel pivot bearings (one pair)
18-19: Add 2 cap-jewels on the pallet
20-21: add 2 cap-jewels on the escape wheel.
22-23: add 2 mainspring barrel jewels
 

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1: Impulse jewel (the part of the balance wheel assembly which receives a kick from the escape lever)
2-5: Balance staff pivot bearings (two pairs - in combinations of one pivot jewel (i.e. jewel with a hole to receive the axle (pivot) of the wheel) and one cap jewel (i.e. jewel without a hole outboard of the pivot jewel, to prevent excessive movement of the balance staff), usually shock protected)
6-7: Escape lever pallets (one pair)
8-9: Escape lever pivot bearings (one pair)
10-11: Escape wheel pivot bearings (one pair)
12-13: Fourth wheel pivot bearings (one pair)
14-15: Third wheel pivot bearings (one pair)
16-17: Center wheel pivot bearings (one pair)
18-19: Add 2 cap-jewels on the pallet
20-21: add 2 cap-jewels on the escape wheel.
22-23: add 2 mainspring barrel jewels
just exactly what type of "jewels" do they use? Ruby? I see red in my Baume Mercier caseback.
 

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just exactly what type of "jewels" do they use? Ruby? I see red in my Baume Mercier caseback.
Lab grown corundum with a chromium impurity. Most people would call that ruby (indeed the two are chemically identical) but the crystal structure of the lab grown variety is totally different to natural ruby. It's is used because it's cheap to manufacture, hard, and provides the lowest friction for the lowest amount of money. Lab grown diamond would technically be better, but lab grown diamonds are still more expensive than lab grown rubies. Plus rubies look nice. Blue lab grown corundum is also seen in a few watches.
 

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Discussion Starter #5
Thanks - are any of those what I'm referring to as the rotor pivot (probably not the correct term)? In other words, the weight that swings to wind the watch? I'm asking because that seems like it would likely be a wear-point, particularly if the rotor is at an angle to its pivot point. It's quite possible my understanding of how things work is incorrect. The 7750 "wobble" seems to discount my concern about the strength or possibility of undue wear at this pivot point. If the rotor can spin like that without causing undue wear leads me to believe that either it is protected from wear or a bit of "slop" in this area isn't an issue. Thanks again, and I apologize for my probable incorrect usage of nomenclature. Any reference material recommended, like maybe an autos for dummies? I don't need to become a master, but a basic understanding would be nice. Right now my knowledge level is "look at the pretty moving things - cool!"
 

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1: Impulse jewel (the part of the balance wheel assembly which receives a kick from the escape lever)
2-5: Balance staff pivot bearings (two pairs - in combinations of one pivot jewel (i.e. jewel with a hole to receive the axle (pivot) of the wheel) and one cap jewel (i.e. jewel without a hole outboard of the pivot jewel, to prevent excessive movement of the balance staff), usually shock protected)
6-7: Escape lever pallets (one pair)
8-9: Escape lever pivot bearings (one pair)
10-11: Escape wheel pivot bearings (one pair)
12-13: Fourth wheel pivot bearings (one pair)
14-15: Third wheel pivot bearings (one pair)
16-17: Center wheel pivot bearings (one pair)
18-19: Add 2 cap-jewels on the pallet
20-21: add 2 cap-jewels on the escape wheel.
22-23: add 2 mainspring barrel jewels
The last two (22-23) are not usual, and rarely, if ever seem on 23 jewel watches, except Chinese ones. For the conventional hand-wind layout you have listed, the 22 & 23 jewels are cap jewels for the 3rd wheel.

Most automatics do not use that layout (in fact, all common ones found in $5000 and cheaper watches). They stop at 16 or 17 on your list.

The remaining jewels are distributed through the automatic winding mechanism. Sometime a jewel, or pair of jewels can be used at the rotor axle, but not always. These days most companies prefer to use a ball bearing. The 7750 used a ball bearing.
 
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Discussion Starter #7
How about ETA movements and Maurice Lacroix? Is there somewhere I can find this info? I have Miyota 9015, Seiko NH36, ETA 2824-2(?), and Maurice Lacroix either 15 or 115 - forget which.
 

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The ML 115 basically is a SW 200 which is an ETA 2824-2 with just one more jewel. Search WUS for more info. All described in detail.
 

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Discussion Starter #9
I tried searching, but the results were overwhelming. Any specific search terms to learn more actual details rather than the more common questions such as "ETA versus xxxx?"
 

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Discussion Starter #11

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Discussion Starter #15
That that must be the best, most accurate, longest lasting watch ever! Why not just make all parts completely out of jewels? Even a full ruby rotor, hands, stem, crown, and even spring bars!



Once was a time when too much jewels was never enough !



Regards,
 
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