1930s-1960s

The launch of reference 3525 marked an important milestone for the brand as it was the very first chronograph wristwatch to be housed in an Oyster case with a water-resistant screw-down caseback along with a screw-down crown. It was available in pink gold, yellow gold, stainless steel or steel and gold combinations. The model is an important milestone reference, as it represents one of the firm’s most important technological advancements and set the design codes of later models to come.

However, one might argue that references 6034, 6234 and 6238 are the true ancestors of the Cosmograph Daytona we know so well today. These models carry all the design codes of the modern Rolex chronograph such as a metal bezel, protruding chronograph pushers, tonneau-shaped case, screw-down crown and screw-down caseback.

Production of reference 6234 was extremely limited. Since the reference’s launch in 1955, approximately 2,300 examples were produced in stainless steel. In contrast, it is recognized that less than 150 examples were cased in 14K or 18K yellow gold. Production of this reference ceased after approximately six years of manufacture and was replaced by reference 6238.

Reference 6238 most resembles the first Cosmograph Daytona, reference 6239. While the tachymeter scale is still printed on the dial, it is notably fitted with the Valjoux caliber 72B, which would later also be fitted on its successor reference 6239. Cased in 18K, 14K yellow gold and stainless steel, the model was fitted with a variety of designs such as a glossy black lacquer dial, “galvanic” dial, multi-scale grené dial, silvered and even with a multi-scale design (such as pulsometer, tachymeter and telemeter).

When analyzing and understanding the Cosmograph Daytona as model, it can be considered a sum of all its parts. It is imperative to understand the breakdown of each component to fully grasp the model as whole. Throughout the history of the model, Rolex has constantly evolved and improved existing technology: the brand itself states that its values are based on “the pursuit of excellence”.

Within this content it is useful to refer to the Rolex “R 20” Catalog, an internal catalog that Rolex sent to retailers and partners each year to classify and assign parts. This was particularly useful during servicing as watchmakers needed to know which components to use. Today, it is very useful for scholars to refer to this book in the interests of “period correctness” and we will thus do so. Furthermore, collectors and scholars gave nicknames or classification types to models or parts and here it is important to understand the usage of the “Mark (Mk)” classification, which designates an evolution in the versions of a part or a product. As an example, Mk 1 is usually older than Mk 2.

Due to parts being exchanged, as discussed in the opening pages, there may be omissions or inaccuracies when cataloging the many parts and correlating them with dates and/or serial numbers.