Chronomètre FB 3SPC

Powered by a mechanical movement featuring a novel construction and a cylindrical balance-spring, the Chronomètre FB 3SPC approaches the core theme of precision from a new angle. It took several years to perfect the adjustments of the regulating organ before obtaining official "chronometer" certification (ISO 3159 standard): a first for such a movement.

 The only cylindrical balance-spring chronometer-certified by the COSC

The mechanical movement of the Chronomètre FB 3SPC is based on a cylindrical balance-spring, a rare watchmaking speciality on which Ferdinand Berthoud himself worked. His nephew, Louis Berthoud, favoured its use in his famous No. 26 decimal watch. The Calibre FB-SPC is the only one of its kind to satisfy the chronometric (precision timekeeping) criteria of the COSC: ISO 3159 certification made possible only by the precision adjustments performed by the Manufacture's watchmakers. Many months of research, testing and fine-tuning were necessary to define the number of coils and the geometry of the terminal curve at the attachment points to optimise rate precision.

Appearing at 9 o'clock, the three main escapement organs – the balance-wheel, pallet-lever and escape-wheel – are thus individualised, distinct and prominent. This ample space dedicated to the regulating organ enables its operation to be admired in full, and the cylindrical balance-spring to be seen beating throughout the three-day power reserve, including through a large water-resistant porthole created in the case middle at 9 o'clock.

A design inspired by pocket watches

While the FB 1 and FB 2 collections belong to the legacy of Ferdinand Berthoud's marine chronometers, the FB 3 collection borrows from the style of the Master's nephew, student and successor: Pierre-Louis Berthoud (1754-1813) known as "Louis Berthoud".

Its round case recalls the curves of pocket watches from the early 19^th century. A single line hugs the curves of the domed crystal and the slender polished bezel of the FB 3 models, while harmoniously extending along the strap and the lugs screwed to the case.

An architecture designed to highlight every detail

The other deep-seated characteristic of Chronométrie Ferdinand Berthoud lies in the desire to create movements with a legible, graphic and three-dimensional architecture. The mainplate is placed at the heart of Calibre FB-SPC and the components are assembled on either side of it.

On the dial side, a close-knit array of six bridges traces curves and lines directly inspired by the work of Louis Berthoud. They are echoed on the back by ten other bridges forming an intimately juxtaposed mosaic.

The hours and minutes appear on a peripheral inner bezel ring, small seconds at 6 o'clock and the power reserve at 2 o'clock. The rest of the dial, deliberately left open, enables one to admire the aesthetics of the movement's components, their arrangement, as well as the surface conditions alternating between chamfered and polished bevels and matt surfaces created by fine sandblasting.

More than 100 hours are required to decorate the 230 components of the movement in order to achieve the ultimate degree of perfection characterising the creations bearing the Chronométrie Ferdinand Berthoud signature.

The Chronomètre FB 3SPC.1 features an 18-carat white gold case, 2N pale yellow gold movement components and an eggshell-coloured dial in sandblasted silver-toned brass.

Production of the Chronomètre FB 3SPC is naturally limited by the capacities of the Chronométrie Ferdinand Berthoud workshop in Fleurier to a maximum of 25 of these timepieces per year.