by Brent Robillard

A history of high-frequency

Last year, I purchased a 1969 Longines Ultra-Chron ref. 8024 from a reputable dealer in Toronto, Canada. I have been on a vintage kick of late. What draws me to watches like this is twofold. There is the retro aesthetic, of course. As in almost all things, the ventral tegmental dopamine shot of attraction is what fires our limbic system in the first place. However, when it comes to watches, I also seek out stories of horological interest. And the Ultra-Chron is a good one that has slipped through the cracks, somewhat, despite reissues like the brand’s 2022 Ultra-Chron Diver and the most recent Ultra-Chron Carbon.

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Key Features of the Longines Ultra Chron 8024

The Ultra Chron 8024 has a very sporty appearance, not unlike the more popular Heuer Monaco (launched two years later in 1969). Its rectangular shape is characterized by the same bowed sides; however, unlike the Monaco, the Ultra-Chron 8024 has inset lugs.

In fact, the lug design also allows space for the 5-link OEM bracelet—which flares to 23mm at the case—to nestle and attain a very comfortable drape while on wrist. At 20mm in lug width, it also provides the wearer with multiple contemporary strap options from something finer and dressier to something more athletic and sportier.

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The dial, for me, is a highlight. It has a sunray finish that varies from slate-grey to plum dependent on the angle and ambient light. The faceted red-gold indices really stand out against this backdrop, as does the partially skeletonized handset. The brand and model logos are three dimensional and applied in the same colour tones. The T-SWISS MADE-T tells us that the dial would have been treated in tritium lume and you can see evidence of this application in the cardinal markers and again in the hands. 

Originally, the case would have had horizontal brushing across the top and along the slab sides, separated by a polished chamfer. However, years of wear have given the watch a satin sheen throughout now. It measures 34mm in diameter and 37.5mm lug to lug with a height just over 10mm that includes the domed and beveled plexiglass crystal.

The aforementioned 5-link bracelet is another feature of this particular piece. Many models appear to have lost the bracelet over time and are sold on leather straps. The stainless steel band is slinky and tapers significantly from 23mm at the lugs to 13mm at the stamped fold over clasp, upon which there are five divets of microadjust. I think the embossed logo is a real gem.

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‘The World’s Most Accurate Watch’

The Utlra-Chron collection was originally launched in 1967 to celebrate Longines’ centenary (at its current location in St. Imier), as a sporty line of dress watches. While the cases and the dials changed, between 1967 and 1972, each was powered by the high-beat calibre 431.

The accuracy craze was ramping up in the 1960s, of course, and would be forever changed by Seiko’s quartz-powered Astron on Christmas 1969. But before this evolutionary disruption, a brief window of mechanical competition had been opened.

Longines had long been experimenting with high-beat (36000vph) stop watches in their sports timing. However, it was Girard Perregaux that would stick the first high-beat movement (the 32A) in a wristwatch in 1966. Seiko, too, would arrive on the scene with their hand-wound 5740C in 1967.

In that era, the average mechanical movement had a beat rate of 2.5Hz, or 18 000vph. So, a watch beating at 36 000vph, or 5Hz, was vibrating at twice the speed. These faster calibres are more precise than those with lower frequencies as the time is measured in shorter intervals. Advancements in materials and lubricants helped reduce the wear and tear of these higher frequencies.

In the calibre 431, for instance, Longines used dry molybdenum bisulphide. The calibre 431 was also adjusted to 4 positions and had a glucydur balance with a KIF-ultraflex shock absorber and an anti-magnetic Nivarox hairspring.

At the time, Longines billed the Ultra-Chron as the “World’s Most Accurate Watch.” Brand advertising claimed that the movement was accurate to within one minute a month, or two seconds a day. While COSC certification would not arrive until 1973, the calibre 431, nonetheless, would have exceeded those standards.

Sometime in 1972, as the quartz crisis settled in, Longines discontinued the redundant calibre 431, and replaced it with the 3Hz calibre 6651, instead.

Final Thoughts

The Longines Ultra-Chron 8024 is very comfortable on wrist. I am a big fan of the bracelet, though it does look good on a variety of straps, as well. There is a surprising amount of depth in the dial and the Plexi crystal exudes a satisfying warmth. Even 55 years later, the calibre 431 has a silky-smooth second-hand sweep, and while I have not hooked it up to a timegrapher, neither have I noticed any unseemly deviations. Collecting vintage watches of any horological significance can be a costly venture. However, the are hidden jewels out there—like this piece—that won’t unduly tax your pocketbook.

You can find excellent examples of the Ultra-Chron in a wide range of case and dial configurations, all featuring the calibre 431, for under $1000 USD. And trust me, there is nothing more satisfying than holding this watch to your ear for that hummingbird hammering of its 431 heart.

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About the author

Brent Robillard is a writer, educator, craftsman, and watch enthusiast. He is the author of four novels. You can follow him on Instagram.

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