April 27, 2015
Omega. A Rare and Early Speedmaster 2915 “Broad Arrow” Chronograph
Manufactured in 1957
Cal. 321 mechanical movement, anti-magnetic soft iron protective cap, black matte dial, luminous baton numerals, luminous “Broad Arrow” hands, outer minute divisions, three engine-turned subsidiary dials for 12 hour and 30 minute registers and constant seconds, steel bezel with tachometer scale calibrated to 300 units, straight lugs, two chronographs buttons in the band, screw back engraved with Seahorse logo, case, dial, and movement signed
Accompanied by an Omega Extract from the Archives
In 1957, Omega launched the first Speedmaster model, the reference CK 2915. It was the first chronograph with a tachometer scale on the bezel, and not on the dial. Produced for only two years, from 1957 through 1959, this references is the most sought-after of Speedmaster references. It is estimated that only between 3300 and 4200 CK 2915’s were produced in total, making the present watch a rare opportunity to collect an all-original and beautifully preserved example.
In 1941, Albert Piguet of the Lemania company designed the caliber 27 CHRO C12 17p for chronographs with three dials (along with the caliber 27 CHRO 17p for chronographs with two subdials). After undergoing several modifications, it was renamed the caliber 321 in 1949. Although the caliber 321 was used in a number of chronograph models in the early 1950’s, including the Omega Seamster, it is best known for its use in the Speedmaster range.
The first generation of caliber 321 movements were used in Speedmaster references 2915, 2998, and 105.002-62. The most notable differences between the first generation of caliber 321 and second and third generations is that the first generation features an arrow-shaped index (later generations feature lozenge-shaped indexes) and a symmetrical clutch bridge (later generations featured asymmetrical clutch bridges).
Reference 2915 cases were produced by Huguenin Freres, and feature a symmetrical shape and straight lugs. The case back either had “Speedmaster” engraved on the edge of the back or had the seahorse logo engraved on the center of the back, as does the present example. Dials were made by the legendary Singer & Co., and produced specifically to be fixed to the caliber 321. For the first five years of production, radium was used for luminous numerals and hands, followed by tritium starting in 1962. The present watch, having been produced in November of 1957, features radium hour markers and hands that have aged to a warm orange-brown tone.
The present reference 2915 features what is known as an “A3 Type Dial”. Pre-professional dials are categorized into the “A” group, and from there divided by variations. A3 Type Dials have the following attributes: an oval-shaped “O” in “Omega”, a small gap between the applied Omega symbol and the text, and minutes counter with short markers. The present watch also features an A2 type of bezel, which has a rounded top “3” in 300, as compared to the A1 type of bezel which features a flat top “3” in 300.
Despite all of these details, what stands out the most on the reference 2915 are the hands. Known as “Broad Arrow” hands, this feature is instantly recognizable. Reference 2915 is broken down into three series - 2915-1 manufactured between 1957 and 1958, 2915-2 manufactured between 1958 and 1959, and 2915-3 manufactured in 1959.
What is interesting about the present watch is that although it is a reference 2915-2, the date of manufacture is from November of 1957. Movement numbers for reference 2915-2 range from 15.996.xxx to 16.648.xxx, yet the present movement number is 15.499.xxx, which not only fits within the known range of 2915-1 examples (15.499.xxx to 15.997.xxx) but makes it one of the earliest movements produced. For vintage watch aficionados, an early example such as the present watch, which is preserved in excellent, original condition, is an opportunity not to be missed.
Source: Moon Watch Only, by Grégoire Rossier and Anthony Marquié