The Omega Speedmaster reference CK2915 was introduced in 1957 as the very first Speedmaster model. It was produced for only a short period – from 1957 through 1959 – before being succeeded by the next reference (CK2998). Within that ~3-year span, Omega issued three sub-references: the 2915-1 (1957), 2915-2 (1958), and 2915-3 (1959). In total, only on the order of a few thousand CK2915 watches were made (on the rough order of 3,000–4,000 pieces across all variants, with only a few hundred in the first batch). This extreme rarity, combined with its historical significance as the “first Speedmaster,” makes the CK2915 highly coveted by collectors.
Case Material and Design
The CK2915 was offered exclusively in stainless steel. Omega’s official archives confirm the case was stainless steel with a screw-in caseback omegawatches.com. The case diameter was approximately 38.5mm, fairly large for its era. The design featured straight lugs (19 mm lug width) without crown guards, giving it a clean, symmetric profile in line with other Omega tool watches of the late 1950s. The watch was marketed as part of Omega’s “Professional” line (alongside the Seamaster 300 and Railmaster in 1957) and had a respectable water resistance of about 50–60 meters (approximately 5 atmospheres) thanks to its sealed caseback and round pump pushers. Early CK2915 casebacks were engraved “Speedmaster” along the outer bevel and were mostly blank in the center (the seahorse logo hippocampus was either absent or very faint on these initial models). By the final 2915-3 in 1959, Omega added the seahorse emblem to the caseback and moved the “Speedmaster” engraving to above that logo, with the caseback itself now featuring a double bevel edge. These subtle caseback differences are one way to distinguish late 2915-3 examples, but they were a transitional change (some 2915-3s may still carry the earlier style back).
Dial Variations and Details
All Omega 2915 models came with a matte black dial (no other dial colors were offered originally). The dial layout was tri-compax (three sub-dials at 3, 6, 9 o’clock for the 30-minute, 12-hour chronograph registers and running seconds) with an outer 1/5th second track for precise time measurement. The design is sometimes described as having a slight “pie-pan” or stepped profile at the dial’s edge leading down to the recessed sub-dials, giving it a subtle depth. Hour markers were painted luminous radium indices (small trapezoid/rectangular marks) for each hour, and a printed “SWISS MADE” appeared at the bottom of the dial. Notably, the 2915 dial featured an applied metal Omega logo (Ω) at 12 o’clock, with the “OMEGA” text and “Speedmaster” name printed just below it. These early Speedmaster dials have a few unique font characteristics: for example, the “O” in “OMEGA” is oval-shaped (wider than it is tall) and the “R” in “Speedmaster” has a long tail on these originals. There is no “Professional” lettering on the dial – that designation was only added years later, so the CK2915 dial simply reads “Omega Speedmaster”. All CK2915 dials used radium luminous material (since tritium was not yet in use), and one hallmark is that the small index markers within the sub-dials are short on the CK2915 (a minor detail that changed in later references). Over time, some original dials have aged to a tropical brown tone, but originally they were black. Overall, aside from normal aging and minor print variations (e.g. slightly “high” or “low” placement of the text relative to the logo), there were no alternate dial colors or major design variants during the 2915’s production.
Movement (Caliber 321)
Powering the CK2915 was Omega’s famed Calibre 321 movement – a 17-jewel, manual-winding chronograph caliber with a column-wheel mechanism. This was the very first movement ever used in the Speedmaster line. In fact, the Cal.321 predated the Speedmaster, having been derived from a Lemania chronograph design (Lemania cal. 27-CHRO-C12) and used in some earlier Omega chronograph models in the Seamaster family. For the Speedmaster in 1957, Omega adopted it as their high-grade chronograph engine. Caliber 321 is renowned for its robust construction and the column-wheel controlled chronograph (machined from a single block, which added complexity and precision). The movement beat at 18,000 vibrations per hour and included features like an anti-magnetic balance spring and a 12-hour chronograph totalizer – essential for the professional timing purposes the watch was intended for. All CK2915 Speedmasters used the Cal 321 throughout the 1957–59 production run, and this same movement would continue to be used in Omega Speedmasters until 1968 when it was eventually replaced by the Cal. 861. The Caliber 321’s presence in the original Speedmaster is a big part of why these models are so historically important, as this is the movement that, in later references, went on to be flight-qualified by NASA and even accompany astronauts to the Moon (though those events happened with slightly later Speedmaster references).
Hands (“Broad Arrow” and Other Styles)
One of the most defining features of the CK2915 is its handset, which earned the watch the nickname “Broad Arrow.” The hour and minute hands on the 2915-1 and 2915-2 are large broad arrow style hands – wide, arrowhead-shaped hands with luminous fill. They are polished steel and have an ample coating of radium lume, making them very bold and legible. This broad arrow hour hand is unique to the first-generation Speedmaster and immediately sets a CK2915 apart from later “Moonwatch” Speedmasters (which eventually used thinner hands). The chronograph seconds hand on the CK2915 is a thin, straight steel hand (uncounted/unpainted, with a pointed tip). Unlike some later references, there was no “lollipop” or large arrow pointer on the chrono seconds in the 2915 – it’s a simple needle hand. The sub-dial hands (for the 3 registers) were slender “leaf” or alpha-style hands in polished metal. All these hands were originally filled with radium lume (except perhaps the small sub-dial hands, which often appear plain steel).
During the final run of this reference, Omega introduced a new style of hands that would carry into the next generation. The sub-reference 2915-3 (1959) is known as a transitional model because some examples were fitted with the classic Broad Arrow hands, while others were factory-fitted with the newer “Alpha” style hands. The Alpha hands are slimmer, pointed baton hands (sometimes also called dauphine-style) with a more refined shape – a stark contrast to the thick broad arrows. Notably, the hour alpha hand used on late 2915-3s was slightly longer than the alpha hand that would be used on subsequent reference 2998, reaching closer to the hour markers. In essence, Omega appears to have been using up remaining Broad Arrow stock while also rolling out the new alpha hands during the 2915-3 production. It’s therefore correct to find a 2915-3 with either Broad Arrow or Alpha hour/minute hands (and similarly either style could be swapped later during service, so verifying originality is tricky). Collectors tend to value the Broad Arrow configuration most (as it is unique to the 2915), but the Alpha-hand 2915-3 watches are equally “authentic” for that reference and historically interesting as transitional pieces.
Other Notable Features and Variations
Bezel: The bezel of the original Speedmaster is another signature element. All CK2915s have a tachymeter scale on the outer bezel – Omega was the first to move the tachymeter from the dial to the bezel on a wristwatch chronograph. On the 2915-1 and 2915-2, this bezel is a brushed stainless steel bezel insert with an engraved “Tachymètre Base 1000” scale. The “Base 1000” notation means the scale is calculated on 1000 units (per hour) – at the time, Omega referred to it as the “Tacho-Productometer” scale in advertising. The steel bezel has numerals and markings filled in black, and it is entirely silver in appearance (no black insert). This specific bezel, used only on the first Speedmasters, has become extremely sought-after by collectors due to its rarity and tendency to be replaced during servicing.
During the production of the 2915-3 (1959), Omega began transitioning to a black bezel. Some 2915-3 examples were fitted with a black aluminum tachymeter bezel insert (still using the same Base 1000 scale) instead of the all-steel version. Other 2915-3 pieces remained with the traditional steel bezel – there doesn’t appear to have been a strict rule, as Omega was likely using whatever parts were on hand in this transitional period. The black bezel on late 2915-3s is essentially the same style that would be standard on the next reference (CK2998). It is still marked “Base 1000” around the 12 o’clock position, but shortly after, Omega changed the calibration: by 1960 (around the 2998-3 sub-reference) they moved to a “Base 500” scale and dropped the word “Base” from the bezel. Thus, the CK2915 is the only Speedmaster reference to feature the “Base 1000” tachymeter bezel, whether in steel or in the rare black variation. Collectors value original Base 1000 bezels highly, as many were replaced with later service parts – an intact steel 2915 bezel today can be as valuable as the watch itself due to scarcity.
Other Characteristics: The crystal on the 2915 was a domed acrylic (hesalite) crystal, as was standard in that era. The crown was a large 7 mm signed crown, facilitating easy winding. The pushers were round “mushroom” style pump pushers (about 4 mm diameter) without any guards. The watch was originally fitted on a stainless steel bracelet – early models came with a flat-link Omega bracelet (reference 7077 in 1957) to match the case. Additionally, the CK2915 did not have the word “Professional” on the dial or case; that designation only came after 1965 when Omega celebrated NASA’s use of the Speedmaster. All original 2915s simply say “Speedmaster.” It’s also interesting to note that Omega initially positioned the Speedmaster within the Seamaster collection (the Omega vintage catalog from 1957 actually calls it “Seamaster Speedmaster”), underscoring its intended use as a rugged sports and racing chronograph (with water resistance akin to a Seamaster). Each of the three sub-references (2915-1, -2, -3) is extremely collectible today. The 2915-1 being the very first version is the most sought-after, but all share the same core design. The -3 stands out as a transitional reference (often a mix-and-match of Broad Arrow vs. Alpha hands and steel vs. black bezel), marking the evolution from the inaugural Speedmaster to the next generation. In summary, the CK2915 “Broad Arrow” Speedmaster, produced only from 1957–1959, introduced all the key elements of the Speedmaster line – from the tri-compax dial and external tachymeter bezel to the robust Cal.321 movement – in a package that has some unique traits (like the broad arrow hands, applied logo, and Base1000 bezel) that would soon change in subsequent models. This makes the original reference 2915 a true icon among vintage sports watches.
