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Zenith is a Swiss watch manufacturer that specializes in chronograph movements, especially its El Primero movement, which was launched in 1969 as the world’s first high-frequency automatic chronograph movement. The El Primero, which means “the first” in Spanish, has a distinctive characteristic of oscillating at 36,000 vibrations per hour (vph) or 5 Hertz (Hz), which enables it to measure elapsed time up to one-tenth of a second. The El Primero movement has been used in many iconic Zenith watches, such as the A386, the De Luca, and the Rainbow Flyback, as well as in other brands’ watches, such as the Rolex Daytona ref. 16520.
However, the El Primero movement is not a static design. Zenith has continuously improved and refined its flagship movement over the years, introducing new versions and variations that offer enhanced performance, functionality, and aesthetics. The latest and most advanced iteration of the El Primero movement is the caliber 3600, which debuted in 2021 in the new Chronomaster Sport model and was later used in the Chronomaster Original and the Chronomaster Open models.
Technical Specifications of the Caliber 3600
The caliber 3600 is not a mere cosmetic update of the El Primero movement. It is a complete overhaul that incorporates modern materials, technologies, and design principles to optimize the movement’s efficiency, reliability, and accuracy. Some of the main technical specifications of the caliber 3600 are:
• A diameter of 30 mm and a height of 6.8 mm, which are slightly larger than the previous dimensions of 29.33 mm and 6.6 mm of the El Primero 400.
• A total of 311 components, which is a reduction from the previous number of 326 components of the El Primero 400. This is achieved by using a single barrel instead of two barrels and by simplifying the column wheel and lateral clutch system.
• A total of 35 jewels, which is an increase from the previous number of 31 jewels of the El Primero 400. This is due to the addition of four jewels in the chronograph mechanism to reduce friction and wear.
• A frequency of 36,000 vph or 5 Hz, which is unchanged from the previous frequency of the El Primero movement. This allows it to measure elapsed time up to one-tenth of a second.
• A power reserve of 60 hours, which is a significant increase from the previous power reserve of 50 hours of the El Primero 400. This is achieved by using a single barrel with a larger mainspring and by reducing friction and energy loss in the movement.
• A silicon escape wheel, which is lighter, harder, and more resistant to magnetism than steel. This improves the stability and durability of the escapement, which is the heart of the movement.
• A stop-seconds mechanism, which allows the user to stop and reset the seconds hand to zero for precise time setting. This feature was previously absent in the El Primero movement due to its high beat rate.
• A central chronograph hand that makes one revolution every ten seconds, instead of one minute. This enables the user to read elapsed time up to one-tenth of a second directly from the dial, without having to multiply by ten. The dial also features a graduated ceramic bezel that indicates one-tenth of a second increments.
• A simplified column wheel and lateral clutch system, which reduces the number of components and screws in the chronograph mechanism. This makes the movement easier to manufacture, assemble, and service, as well as more robust and reliable.
• A partially skeletonized rotor, which reveals more of the movement’s inner workings and adds a touch of modernity to its appearance.
Technical Performance of the Caliber 3600
The caliber 3600 is not only a technical marvel but also a practical and functional one. It offers several advantages over its predecessor, such as:
• A higher accuracy, thanks to its silicon escape wheel and its ability to measure one-tenth of a second. Zenith claims that the caliber 3600 has an average deviation of only +/- 3 seconds per day, which is well within the COSC chronometer standards.
• A longer autonomy, thanks to its 60-hour power reserve. This means that the user can leave the watch unworn for more than two days without having to wind it or reset it.
• A better legibility, thanks to its central chronograph hand that makes one revolution every ten seconds and its ceramic bezel that indicates one-tenth of a second increments. The user can easily read elapsed time at a glance, without any confusion or calculation.
• A more versatile design, thanks to its simplified column wheel and lateral clutch system. The caliber 3600 can be adapted to different dial layouts and configurations, such as tri-compax (three sub-dials), bi-compax (two sub-dials), or open heart (exposed escapement).
Technical Aesthetics of the Caliber 3600
The caliber 3600 is not only a functional improvement but also an aesthetic one. It has a refined and elegant appearance that showcases Zenith’s craftsmanship and heritage. Some of the visual highlights of the caliber 3600 are:
• The blue column wheel, which is a signature element of Zenith’s chronograph movements. It adds a splash of color and contrast to the movement’s silver-tone finish.
• The star-shaped rotor, which is another emblematic feature of Zenith’s movements. It is partially skeletonized to reveal more of the movement’s inner workings and to create a dynamic and captivating effect.
