The Tissot caliber 2400 is a manual-winding mechanical movement introduced in the 1950s, and it stands as the foundational model of Tissot’s compact 24xx movement family. Engineered for small, elegant wristwatches, particularly ladies’ watches and slim unisex dress models, the 2400 reflects Tissot’s mid-century focus on precision, economy, and durable mechanical performance in compact formats.

Overview of the Tissot Caliber 2400

The Tissot 2400 was designed to be:

• Thin and compact, suitable for smaller watch cases

• Simple in construction, making it easy to service

• Reliable for everyday wear, with a smooth manual wind

It typically powers watches with:

• Hour and minute hands (central)

• Often a small seconds subdial at the 6 o’clock position

The movement was housed in cases ranging from 24 mm to 30 mm, often found in gold-plated, steel, or solid gold cases. Watches using this caliber were frequently sold under Tissot’s Antimagnetique, Seastar, and Stylist lines.

Technical Specifications

• Type: Manual winding

• Functions: Hours, minutes, small seconds

• Jewels: 15

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

• Power Reserve: Approximately 40 hours

• Diameter: ~23 mm (approx. 10½ lignes)

• Height: ~3 mm

• Shock Protection: Not present in early models; later production included Incabloc-type systems

• Finish: Functional Swiss industrial style with brushed or matte plates, Tissot-stamped bridges, and often blued screws

The movement architecture is based on the Swiss lever escapement, with a traditional gear train layout for consistent performance and servicing convenience.

Maintenance and Servicing

The 2400 is a vintage movement and, like all mechanical calibers of its age, requires regular service every 4 to 6 years to maintain accuracy and prevent wear.

A standard overhaul includes:

1. Complete disassembly of the movement

2. Ultrasonic cleaning of each component

3. Inspection and replacement of worn parts (especially the mainspring, pivots, and escapement components)

4. Lubrication with modern synthetic oils

5. Reassembly and regulation in multiple positions

6. Case cleaning and, where applicable, gasket replacement

Because parts are no longer in production, donor movements may be used when component replacement is necessary.

Common Points of Wear

• Mainspring fatigue reduces amplitude and power reserve

• Balance staff pivots may wear if shock protection is absent or damaged

• Small seconds gear experiences continuous load and may develop wear

• Stem and crown may become worn due to frequent winding

• Setting mechanism parts (keyless works) may wear or misalign over time

Despite these age-related issues, the 2400 remains relatively easy to restore due to its straightforward construction.

Usage Tips

• Wind gently once per day, stopping when resistance is felt

• Avoid exposing the watch to moisture or strong magnetic fields

• Store in a dry, cushioned box, ideally face-up when not in use

• If unused for long periods, have it serviced before daily wear resumes

Collectibility and Appeal

The Tissot 2400 is modest in complexity but has lasting appeal for collectors and vintage enthusiasts because of its:

• Role as the base model in the 24xx series

• Mechanical simplicity and smooth operation

• Use in elegant mid-century designs

• Affordable entry into vintage Swiss mechanical watches

It’s particularly sought after by those looking for a refined, vintage ladies’ or unisex watch with genuine Swiss heritage.

Conclusion

The Tissot caliber 2400 is a compact, hand-wound mechanical movement that embodies the principles of precision, simplicity, and elegance. As the root of Tissot’s 24xx family, it laid the groundwork for several successful successors. With proper maintenance and respectful handling, the 2400 remains a reliable and charming piece of vintage horology, ideal for those who value the craftsmanship of classic Swiss watchmaking.