The Tissot caliber 2403 is a manual-winding mechanical movement produced during the 1950s and 1960s, part of the brand’s compact 24xx movement family. Like its sibling calibers (such as 2400, 2404, and 2451), the 2403 was developed for elegant time-only wristwatches, particularly ladies’ watches and small unisex models, where space constraints demanded a movement that was thin, reliable, and easily serviceable.

Overview of the Tissot Caliber 2403

The caliber 2403 is typically found in watches with:

• Manual winding

• Central hour and minute hands

• A small seconds subdial at 6 o’clock (in most versions)

Watches equipped with this movement were commonly part of the Tissot Antimagnetique, Stylist, or Seastar series. These were often housed in small-diameter cases (around 25–30 mm), made from stainless steel, gold-plated brass, or even solid gold. Dials were simple, elegant, and highly legible, designed to complement the slim profile of the movement.

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: Often equipped with Incabloc or similar system (in later production)

• Finish: Industrial Swiss finish with matte or lightly brushed bridges, often Tissot-stamped

Like other movements in the 2400 series, the 2403 uses a Swiss lever escapement, and its layout is designed to be easily maintained by qualified watchmakers.

Maintenance and Servicing

Being a vintage movement, the 2403 requires regular maintenance every 4 to 6 years to keep it running accurately and to prevent long-term wear. A typical full service includes:

1. Disassembly of all movement components

2. Ultrasonic cleaning of parts

3. Inspection of pivots, jewels, and the mainspring

4. Replacement of worn components, using donor movements if necessary

5. Lubrication with modern synthetic oils

6. Reassembly and regulation

7. Cleaning the case and replacing seals (if fitted)

Due to the age of these watches, some may require custom adjustments or part fabrication during servicing, especially if they have seen extensive wear.

Common Wear Areas

• Mainspring weakening over time, reducing power reserve

• Balance pivots and jewels, particularly vulnerable if the watch has not been lubricated regularly

• Small seconds train, under constant load, can show tooth wear

• Crown and stem, subject to wear due to frequent winding

• Setting mechanism components may wear or become misaligned over time

Despite these typical aging issues, the 2403 is known for being durable and forgiving, especially when serviced correctly.

Handling and Use Tips

• Wind once per day, stopping when resistance is felt

• Avoid exposing the watch to water or high humidity

• Keep away from magnetic fields, which can affect timekeeping

• Store in a dry, cushioned case, preferably dial-up when not in use

Collectibility and Appeal

The Tissot 2403 is not a rare movement, but it holds enduring appeal for several reasons:

• Compact mechanical reliability for smaller vintage watches

• Historical value as part of Tissot’s post-war production

• Simple, elegant styling that still resonates with collectors

• Affordability, making it a great entry point into vintage Swiss watches

Collectors appreciate it for its balance of practicality and vintage charm, especially in well-preserved examples.

Conclusion

The Tissot caliber 2403 is a well-crafted, small-format manual movement from a time when Swiss precision and elegant watch design went hand in hand. Built for long-lasting performance and ease of service, it remains a solid option for vintage collectors who appreciate the timeless appeal of mid-century mechanical timepieces. When maintained properly, the 2403 offers many more years of reliable performance and understated beauty.