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The Rolex Cosmograph History

October 3, 2018

BY Eric Wind


The Daytona has become synonymous with Rolex chronographs; however Rolex was manufacturing watches with chronograph movements for several decades before the Daytona name became a mainstay in their catalogue.

The Rolex Cosmograph History has many changes.

Since the Pre-Daytona Chronograph ref. 6234 circa 1957 there have been many changes.

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A Rolex Cosmograph History Lesson

Rolex first started experimenting with mechanical chronographs during the 1930s, but it was not until 1963, with the introduction of the reference 6239, that an actual name was given to their chronograph watch line.

Although many consider this reference to be the first Daytona, it was not until almost 1965 that the Daytona name actually made its debut appearance on the dial. In those two years before the addition of the Daytona name, Rolex’s chronograph line was known simply as the Cosmograph, a name that still remains on Daytona dials today.

The Rolex Daytona 6239 was the first Daytona ever made

The Rolex Daytona 6239 was the first Daytona ever made with inverse colors

The reference 6239 marked the first time in Rolex history that inverse colors were used for the chronograph registers (previous Rolex chronograph dials were entirely monochromatic). Additionally, it also marked the first time that the tachymeter scale was engraved on the bezel, rather than printed on the dial surface.

Changes Through The Ages

Although relatively minor, these two changes made for a significantly different visual appearance that gave the vintage sports reference 6239 a much more chunky and sports-oriented look than the Rolex chronographs that preceded it. These two characteristics were carried over onto subsequent references, and every Daytona that Rolex has manufactured since the reference 6239 has had its tachymeter scale on its bezel rather than its dial.

In addition to pre-dating the arrival of the Daytona name, the reference 6239 also pre-dates the implementation of screw-down pushers for the chronograph buttons. Much like the first iterations of Rolex chronographs, the reference 6239 utilizes pump-style pushers that offer significantly less water resistance than the screw-down style that is used on the “Oyster” Daytona, which first made an appearance with the reference 6240.

While many think of Rolex’s Cosmograph Daytona as a watch with a 40mm case diameter, the first Rolex chronographs – including the reference 6239 – had 37mm cases.  The Rolex Daytona did not see the increase in size until the arrival of the reference 16520, which also marked the introduction of a sapphire crystal to Rolex’s Cosmograph Daytona line of watches.

The Rolex Daytona 116520 Took 16 Years To Develop

The 16520 Daytona was the first increase in size the chronograph saw

The Cosmograph name frequently gets left out when discussing Rolex’s Daytona; however, it is the Cosmograph name that truly marks the point in history when Rolex’s legendary chronograph first started to take its final form.

That being said, the reference 6239 Cosmograph also lacks a number of traits that are characteristic of contemporary Daytona chronographs, such as a self-winding movement, 40mm case diameter, screw down chronograph pushers, and a sapphire crystal. In this way, the reference 6239 is representative of a crossroads between the early Rolex chronographs and the contemporary Daytona watches that would follow.

The Rolex Daytona 116500LN made a big splash at Baselworld

The Rolex Daytona 116500LN made a big splash at Baselworld, and has come a long way since its inception

Although frequently forgotten in conversation, the Cosmograph name is printed on the dial of every Rolex chronograph that leaves the factory today. Additionally, due to its classic good looks and important place within 50-year plus Rolex chronograph history, the reference 6239 Rolex Cosmograph has become one of the most desirable vintage Rolex watches for collectors to own.






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