Time Spec: 1970s British Military Asymmetrical Chronographs

For over a decade, four companies–Hamilton, CWC, Newmark, and Precista–supplied simple, sturdy, 30-minute chronographs to the British military. Their classic black, two-register dials, workhorse Valjoux 7733 movements, and asymmetrical case design led to high usability and keep them popular and influential today.



In the early 1970s, while the United States maintained and grew its military in response to the conflict in Southeast Asia and its Cold War with the Soviet Union, the British government was in the process of reducing its armed forces in both size and cost. As a very small part of these austerity measures, the UK Ministry of Defense (MoD) revised the Defense Standard (DEF-STAN) that prescribed the design characteristics of military pilots’ watches to allow for cheaper, commercially available movements to be used.

This change allowed manufactures to begin using one of the classic workhorse chronograph movements of the 1970s–the Valjoux 7733. This movement and the unique case design of these watches combined to become the British military pilot’s watch throughout the ’70s and into the early ’80s, before eventually being replaced by cheaper quartz chronographs. Today we’ll take a look at the design features that made (and keep) these chronographs so popular, we’ll discuss the collector market for these watches today, and we’ll wrap up with some modern watches whose pedigrees are a direct line to these classic chronographs.



DefStanDEF-STAN 66-4 (Part 2) included a small but significant change from its first issue in April 1969 to its second issue in April 1970. The latter changed the standard to allow for pilot’s chronograph cases to feature either one or two “pushpieces,” or buttons, to control the watch’s chronograph function. That change allowed for manufactures to use the Valjoux 7733 movement we’ll discuss below. It also balanced the case vertically in a way that it was not before, placing one button on top and one below the crown.

What it did not change was the asymmetry of the case from left to right. A design element intended to protect the crown and pushers from accidental bumps during use, the case is thicker on the right side than on the left. As the key feature of these watches, they are often referred to as “asymmetrical chronographs.”

Along with the asymmetrical case, nearly all design elements of the watches were specified in DEF-STAN 66-4 (Part 2), and all four brands share nearly identical appearance. The dials are black with white markers, illuminated 12 and six numerals, and illuminated dots at each hour marker. The time is displayed by central hour and minute hands and a running seconds hand in the nine o’clock sub-dial. The chronograph time is counted by the center seconds hand and a 30-minute counter in the three o’clock sub-dial. The chronograph is activated and stopped by the top pusher, then reset by the bottom pusher.

Processed with VSCOcam with se3 preset

The one obvious external difference between the four watches is the company branding that appears below 12. Below that, each watch bears the circle “T,” indicating that tritium lume was used on the illuminated numerals, indices, and hands. The Hamilton and CWC dials also display the “broad arrow,” or “pheon,” a mark found on British military equipment to signify that the item is property of the government (you’ll see the mark again when we get to the case back, and on other British military watches we’ll cover in future articles).

Click here to learn more about tritium and luminescence.

Military Markings

casebacksAs is true with all military equipment, issuing and tracking of these watches was an important job. To aid in that process, these watches were marked with four important pieces of information: the item type number, the issuing agency, the year of issue, and the individual watch issue number. These watches were built in accordance with the “924-3306” type, so they all carry that numbering. They were issued by two agencies in the UK and one in Australia and have issuing numbers that correspond with each agency:

• 0552 – Royal Navy (RN)
• 6BB – Royal Air Force (RAF)
• 6645-99 – Royal Australian Navy (RAN)

In some cases, these watches were issued to one unit, then returned and reissued through another unit. In the third and fourth examples shown here, RN-issued watches were reissued to the RAF. In one case, the “0552” marking was routed out and the “6BB” marking stamped on top of the same location. In the other, the RN markings were struck through with lines and the RAF markings engraved above.

Under the agency and item type numbers, we see the broad arrow, signifying that the watch is “property of the crown.” Below that are the specific watch serial number–different on each watch–and the two-digit year of issue. Hamilton was first to make these watches, with examples starting in 1970. CWC began production in 1973, and were eventually followed by Newmark in 1980 and Precista 1981.


Processed with VSCOcam with b5 presetA two-button, two-register, 30-minute chronograph movement, the Valjoux 7733 was used by a wide variety of watch makers throughout the 1970s to power attractive, affordable chronographs. With a strong, proven design history and parts compatible across the 773x range, the 7733 was a good choice for simple chronograph watches and made a great movement to power these British pilot’s watches. The movement is hand-wound via the crown at three, and the chronograph functions as described above. The movement ticks strongly at 18,000 beats per hour.


Because of their minimal, attractive design, quality construction, and military connections, all variations of these four watches have become very collectable in recent years. With production of only one year each, the Newmark and Precista models are the rarest, and good examples often attract the highest prices at around $1,500-2,000. CWC and Hamilton models are found fore sale more often, and nice examples typically sell in the $1,000-1,500 range.

With many of these watches in military use for over a decade, and easy parts interchangeability between the models, many examples exist with a combination of manufacturer’s parts (for example, a single watch might have a Hamilton signed dial, CWC signed movement, and case back from a later issue). Finding a watch with combined parts does not necessarily mean it is inauthentic; parts swapping like this in known to have been performed by MoD watchmakers who had access to different parts stocks at different times. As with all military watches, buying a piece with known provenance is always the best way to go. If you can’t find one for sale from an original owner, buying one from a respected dealer or member of the collector community is equally recommended.

Modern Influences

Throughout the article, we’ve mentioned the popularity these watches currently enjoy. It should therefore be no surprise that modern companies have tried to capitalize on that popularity by reissuing or recreating these watches. CWC still manufactures watches under UK DEF-STAN specifications and has reissued this chronograph with a modified hand-wound Valjoux 7760 movement. It’s for sale at Silverman’s for around $1,500. The Precista brand trademark is now owned by Eddie Platts of TimeFactors, and remakes of the watch with Seagull ST-19 movements were available for around $425, though they have been discontinued. Both examples provide the classic look of the asymmetrical chronograph with modern movements and factory warranties.


The final example of this classic design being remade as a modern timepiece is the Pilot Pioneer by Hamilton. Click here for a full review of that piece.


Photo Credits:
Hamilton – “tempussuisse”
Trio – “hogpole,” “watchitdude”, “Geronimo”
Casebacks – Anna, “hogpole,” John “Flightpath,” Joel M, MKII Watches
Movement – MB Radio
Reissues – CWC Watches, TimeFactors

Related Posts
Brandon was raised in a military family, the son of an Army pilot and engineer. An early fascination with all things mechanical developed into a love of watches that remains today. Brandon holds a pair of degrees in experimental psychology and works as a human factors test engineer for Army aviation systems.