Counting Jewels with Omega – Part II
June 3, 2016
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Since the emblem of the Omega manufacture and the beginning of the journey can be identified on good reasons with then newly tailored 19" lig. caliber, developed by François Chevillat, it is worth offering a small tribute to it's creation by adapting this small grading study on the evolution of the 19" caliber, being the most versatile of all Omega pocket watch calibers, with many of it's features and transformations visible later to the rest of the dynasty.

The below chart represents the standard 4 grade designation (A, B, C and D) for the Omega 19" lig. Lépine caliber family, available since 1894. Although in 1901, a new and improved family of calibers has been introduced, the old family remained in production at the same time with the new ones, for many years to come.


Omega A Quality - 7 jewels:

Since 1894, with the exception of the Goliath 59.8D caliber, Omega has never manufactured a pocket watch movement with less then 7 jewels. The 7 jewels stands for A quality when grading your movement.

all 7 jewels are within the escapement assembly
4 in Chatons, to the balance staff - 2 hole jewels, 2 cap jewels
1 Roller jewel
2 Pallet jewels
Other features: cut balance wheel, double roller, flat hairspring made of tempered steel, adjusted in 2 positions with an accuracy variation of under a minute per day.
The going train pivots have metal bushings instead of jewels.


Omega B Quality - 15 jewels:

4 in Chatons, to the balance staff - 2 hole jewels, 2 cap jewels
1 Roller jewel
2 Pallet jewels
2 Pallet pivot hole jewels
2 Escape wheel pivot hole jewels
2 3rd wheel pivot hole jewels
2 Seconds wheel pivot hole jewels
Other features: cut temperature compensated balance wheel, double roller, Breguet hairspring made of tempered steel, polished compass, straight line Lever, visible pallets, adjusted in 2 positions with an accuracy variation of under a minute per day.
The center wheel pivots have metal bushings instead of jewels.


Omega C Quality - 15 jewels:

7 jewels in Chatons, 4 to the balance staff - 2 hole jewels, 2 cap jewels
1 Roller jewel
2 Pallet jewels
2 Pallet pivot hole jewels
2 Escape wheel pivot hole jewels (1 in Chaton)
2 3rd wheel pivot hole jewels (1 in Chaton)
2 Seconds wheel pivot hole jewels (1 in Chaton)
Other features: fine finishing ebauche, superior quality jewels, Anglage, cut temperature compensated balance wheel, double roller, high quality Breguet hairspring made of tempered steel, polished compass, swan neck regulator, straight line Lever, visible pallets, polished and faceted wheels and tooth, movement secured in a expansion ring between movement and case, adjusted in 5 positions with an accuracy variation of under a minute per week, with a 1st Class, Bulletin de Marche from Bienne Observatory - on request -, enamel dial with stepped seconds dial.
The center wheel pivots have metal bushings instead of jewels.


Omega D Quality - 16 jewels:

11 jewels in Chatons, 4 to the balance staff - 2 hole jewels, 2 cap jewels
1 Roller jewel
2 Pallet jewels
2 Pallet pivot hole jewels
2 Escape wheel pivot hole jewels (2 in Chaton)
2 3rd wheel pivot hole jewels (2 in Chaton)
2 Seconds wheel pivot hole jewels (2 in Chaton)
1 Center wheel pivot hole jewel (1 in Chaton)
Other features: Chronometer class, top finishing ebauche, best quality jewels, all in Chatons, best quality wheels and pivots, Anglage, 1st quality cut temperature compensated balance wheel, double roller, 1st quality Breguet hairspring made of tempered steel, polished compass, snail regulator, straight line Lever, visible pallets and ruby pallet stones, chronometer quality escape wheel, polished and faceted wheels and tooth, jeweled center wheel above (exception: and below, for 17 jewels movements), adjusted in 5 positions and extreme temperatures, with an accuracy variation of under a minute per month, with a 1st Class, Bulletin de Marche from Bienne (or Neuchatel or Geneva) Observatory, enamel dial with stepped seconds dial.


In the above chart we can notice a few variables and differences in construction. All these differences are part of the grading process. 
However, when grading an Omega movement, we have to take in consideration more then what we see.
Just to name a few: Balance cock shape, Regulator, Setting mechanism, Bridge shape construction, Movement finishing, Case material, Dial, Handset, etc.
Except A Quality, each grade has it's own declination. For example, in 1894, the Bs declination was the top of the B Quality, found only in gold pieces, while the DD declination was the top of the D Quality production.

In a following chapter we will focus on the various Omega balance cocks, regulators and their evolution, in order to determine jewel count, caliber and correct caliber abbreviation.

*** Although a work in progress at the moment, a wider illustrated chart, containing at least the 19" caliber family, caliber abbreviation and technical specs, should be available by the end of the year.

If you wish to bring your contribution to the project, don't hesitate to send us pictures with your Omega pocket watch, including case and movement by email, at: [email protected]

 


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