The Valjoux caliber 24 is a manual-winding chronograph movement introduced in the mid-20th century by Valjoux (Fabrique d’Ébauches Valjoux SA), a leading Swiss movement manufacturer known for producing high-quality chronograph calibers. The Valjoux 24 is part of the broader Valjoux 23 family, a prestigious series of column-wheel-operated chronograph movements widely used in high-end Swiss watches from the 1930s to the 1970s.

Overview of the Valjoux 24

The Valjoux 24 is a derivative of the Valjoux 23, nearly identical in architecture and performance, but it includes an added GMT (second time zone) or 24-hour hand functionality. This feature made it particularly suitable for military, aviation, and traveler chronographs during a time when dual-time complications were highly valued by professionals and enthusiasts.

Key Specifications

• Type: Manual-winding chronograph

• Chronograph Mechanism: Column wheel

• Jewels: 17

• Frequency: 18,000 vibrations per hour (2.5 Hz)

• Power Reserve: Approx. 45–48 hours

• Diameter: 13 lignes (~29.5 mm)

• Height: Approx. 5.9 mm

• Functions:

  • Hours, minutes

  • Small seconds at 9 o’clock

  • 30-minute chronograph counter at 3 o’clock

  • Central chronograph seconds

  • Additional 24-hour (or GMT-style) hand

• Shock Protection: Incabloc (in most later versions)

Movement Features

• Column-wheel actuation: Offers precise and smooth chronograph engagement

• Horizontal coupling system: A traditional setup where chronograph wheels mesh side by side

• Finishing: High-grade Swiss finish, often with Geneva stripes or perlage in luxury implementations

• Durability: Highly regarded for long-term reliability, especially when regularly serviced

Applications

The Valjoux 24 was used in military chronographs, pilot watches, and high-end travel watches from Swiss brands such as:

• Heuer

• Enicar

• LeCoultre (Jaeger-LeCoultre, in some tool watches)

• BWC, Excelsior Park, and other specialty brands

It was particularly prized in aviation circles for combining chronograph and dual-time functions in a robust and legible layout.

Servicing and Parts

• Service Interval: Every 4 to 6 years

• Complexity: Requires a watchmaker experienced with column-wheel chronographs

• Parts Availability: Scarce due to its age and limited production; sourcing may involve donor movements

• Value: Restored examples of watches using this caliber are increasingly collectible and valued in the vintage market

Collectibility and Legacy

Collectors appreciate the Valjoux 24 for its:

• Rarity compared to the standard Valjoux 23

• Functional sophistication, offering both chronograph and GMT capability

• Mechanical refinement, especially with column-wheel construction

• Historical importance in tool and pilot watches

Its combination of mechanical complexity and practical functionality makes it a desirable collector’s movement, especially when found in well-preserved or military-issued watches.

Conclusion

The Valjoux caliber 24 is a rare and refined manual-wind chronograph movement with a 24-hour/GMT function, derived from the legendary Valjoux 23. Built with a column-wheel system, it delivers smooth operation and excellent long-term performance. Though it is far less common than its base caliber, it remains a highly collectible and historically significant movement, especially valued by enthusiasts of vintage aviation and dual-time chronographs.