Certina Caliber 25-36: A Robust Time-Only Automatic Movement

The Certina Caliber 25-36 is one of the later additions to the Swiss brand’s distinguished 25-series of automatic mechanical movements. Developed during the 1960s and 1970s, this caliber represents the brand’s commitment to precision, durability, and timeless design in a clean, date-free configuration.

Like other 25-series movements, the 25-36 is compact, efficient, and highly serviceable—attributes that make it a go-to for both collectors and watchmakers restoring vintage Certina timepieces.

Technical Specifications

This movement features no date or additional complications, emphasizing reliability, legibility, and mechanical purity.

Mechanical Design and Features

The 25-36 is nearly identical in structure to previous models like the 25-35, but includes slight refinements in component layout and production tolerances. It was built for long-term performance, particularly in everyday wear conditions.

Key Technical Highlights:

• Bi-directional automatic winding, ensuring quick power reserve recovery with minimal wrist movement

• A central seconds hand, offering a clean and modern dial layout

• Simplified gear train design, leading to better power transmission and reduced friction

• Shock-protected balance, improving resilience against physical impacts

• Optimized bridge architecture for easier servicing

These features combined make the 25-36 an excellent example of Certina’s mid-century mechanical engineering philosophy: functional durability with understated elegance.

Applications in Certina Watches

Watches powered by the 25-36 are usually modest in appearance but solidly built, intended for daily use rather than ornate luxury. They often appear in the DS (Double Security) line or in time-only automatic dress models.

Watch characteristics with the 25-36 include:

• 34–36 mm case diameters, commonly in steel or gold-plated finishes

• Minimalist dials, often with baton indices or subtle markers

• No date window, favoring perfect symmetry

• Snap-on or screw-down case backs

• “Certina Automatic” dial printing, typically in a refined sans serif typeface

These models appealed to customers who wanted Swiss reliability in an affordable, tasteful package—a philosophy that resonates today among vintage enthusiasts.

Watchmaker Insights

The Certina 25-36 is known as a watchmaker-friendly movement, particularly because it shares parts with earlier 25-series movements and remains straightforward to service.

Key Servicing Points:

• Use Moebius 9010 oil for the train and escapement, and 9501 grease for keyless and automatic parts

• Rotor bearings and reverser wheels should be cleaned and checked for wear

• Mainspring barrel may need replacement if amplitude is below 240°

• Post-service, these movements generally regulate to ±10–15 seconds/day

• Absence of a calendar mechanism reduces service time and risk of mechanical failure

Because of the simplified mechanism, reassembly and regulation are often easier than with date-equipped or high-beat calibers.

Collectibility and Value

The Certina 25-36 holds solid appeal among collectors, especially those looking for:

• No-date, symmetrical dial designs

• Affordable Swiss vintage watches

• A platform for restoration or modification

• Durable, well-tested calibers for daily wear

It is especially appreciated for its balance of quality and simplicity, making it a hidden gem in the world of vintage automatics.

Conclusion

The Certina Caliber 25-36 embodies everything that made Certina successful in the post-war watch boom: precision, ruggedness, and simplicity. As a time-only automatic, it captures a timeless aesthetic that appeals to both modern minimalists and vintage purists. Whether you’re restoring a classic Certina or simply seeking a reliable vintage movement, the 25-36 delivers dependable Swiss performance in a clean, uncluttered package.