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ETA Mechanical movements Caliber Product Line Winding Diameter Height Jewels Frequency Running time VPH Hz; 2671 [1] Mecaline automatic 17.2 4.8 25 28800 4 38 2678 [2] Mecaline automatic 17.2 5.35 25 28800 4 38 2000-1 [3] Mecaline Specialities automatic 19.4 3.6 20 28800 4 40 2681 [4] Mecaline automatic 19.4 4.8 25 28800 4 38 2094 [5]
Watch movements that could compete for accuracy certification at the observatory had typically been specifically built for that purpose alone, they were slow beat movements, oscillating at from 18,000 to 21,600 bph, typically with oversized balance wheels, tweaked and prepared by the best watchmakers often for many years to render ultimate ...
Each movement is individually tested for several consecutive days, in five positions and at three temperatures. Any watch with denominations "certified chronometer" or "officially-certified chronometer" contains a certified movement and matches the criteria in ISO 3159 Timekeeping instruments—wristwatch chronometers with spring balance ...
Each specific watch movement is called a caliber. [3] The movement parts are separated into two main categories: those belonging to the ébauches and those belonging to the assortments. [2] In watch movements the wheels and other moving parts are mounted between two plates, which are held a small distance apart with pillars to make a rigid ...
The company built the Elgin National Watch Company Observatory in 1910 to maintain scientifically precise times in their watches. The company produced many of the self-winding wristwatch movements made in the United States, beginning with the 607 and 618 calibers (which were bumper wind) and the calibers 760 and 761 (30 and 27 jewels respectively).
Every watch movement that the company produced through the early 1950s was engraved with an individual serial number. That number can be used to estimate the date of production. Volunteers have created a database of Waltham serial numbers, [103] models and grades, [104] and descriptions of observed watches. [105]
Patriot Watch (reg. 16 Apr 1889, pocket watches) [30] Profundus (first diver's wristwatch with integral depth gauge, 1966) [30] QuickTrain (earliest commercially produced wrist watch with faster beat movement) [12] Racine (watches sold in North America) [12] Racine Royale (watches sold in North America) [12] Railroad Watch (reg. 12 Aug 1879) [27]
Occasionally, a watch movement intended for a hunting case (with the winding stem at 3:00 and sub second dial at 6:00) will have an open-faced case. Such watch is known as a "sidewinder." Alternatively, such a watch movement may be fitted with a so-called conversion dial, which relocates the winding stem to 12:00 and the sub-second dial to 3:00.