SIHH 2018: Ferdinand Berthoud - Chronomètre FB 1R.6-1

With its original regulator-type display and its ultra-resistant carburised stainless steel case, the new Chronomètre FB 1R.6-1 by Ferdinand Berthoud transposes into contemporary language the pursuit of excellence undertaken by the eponymous master horologist, clockmaker to the French King and Navy.

The 44 mm x 13.95 mm case is composed of a steel cylinder whose molecular structure has been reinforced by a thermo-chemical process involving the diffusion of vapour-phase carbon, thereby guaranteeing an exceptional surface hardness of 1200 Vickers and making it extremely robust. It is also exceptionally corrosion-resistant and biocompatible.

Two octagonal-shaped stainless steel side pieces give the case a characteristic shape including two lateral portholes at 2 and 11 o’clock providing a chance to admire the chain-and-fusee mechanism in action. These two openings are complemented by a screw-down stainless steel case-back fitted with glare-proofed sapphire crystal enabling observers to appreciate the high-quality finishing.

The construction of the Chronomètre Ferdinand Berthoud IR.6-1 sets it apart from all existing regulator-type displays. In fact, the vertically satin-brushed and black rhodium-plated dial is the rear side of the complication plate.

Of the three small apertures, the first serves to show the hours, offset at 2 o’clock and appearing on a glare-proofed sapphire crystal disc bearing transferred Arabic numerals striking a pleasing contrast with a white background. The second opening features an original power-reserve display mechanism, distinguished by a large dial cut-out revealing part of the finely sandblasted and black rhodium-plated mainplate. Located in the centre of the minutes counter, the third aperture displays a hand-engraved “pyramid” motif inspired by an openworked Ferdinand Berthoud astronomical clock belonging to the collection of the L.U.CEUM watch museum.

Meanwhile, the seconds appear around the rim of the dial on a flat inner bezel ring made of black rhodium-plated, bead-blasted and chamfered nickel silver.

The design of the hands is a reinterpretation of various hand shapes used by Ferdinand Berthoud in his numerous timepieces. Great expertise is required to reproduce their complex shapes. The minutes hand is crafted in 18-carat gold, while the seconds hand is made of bronze and the fixed hour-markers and power reserve hand are made of steel.

The 3 Hz (21,600 vph) hand-wound movement features 18 nickel silver bridges framed by polished titanium pillars surrounding the mechanical organs. This construction is typical of 18th century marine chronometers. The architectural approach is picked up in the design of all the components, and especially in the symmetrical equilibrium of the movement.

The distinctive nature of the FB-T.FC.R calibre lies in its inverted upside-down barrel and fusee, and particularly in the fact that both elements are suspended, meaning held on only one side. A patent has been filed for this construction which saves precious millimetres. At 9.89 mm thick, the movement of the Chronomètre Ferdinand Berthoud FB 1R.6-1 remains extremely thin for its category despite the regulator-type display and the new power-reserve indication.

Barrel and fusée are linked by a chain comprising no less than 474 steel links, including more than 300 pins measuring barely 0.30 mm in diameter and all hand-assembled. The chain measures a total 28 cm long and the maximum tension exercised upon it once in place amounts to three kilos.

When the mainspring is associated with a fusée, the barrel drum turns in one direction when the spring winds down and in the opposite direction when it is wound up, thus causing the chain to wrap around the drum.

A patent has been filed for the sophisticated 53-hour power-reserve indication mechanism. Visible through a cut-out in the half-bridge on the case-back side, a truncated cone moves up and down along an arbour connected to the barrel. This suspended cone is topped by a feeler spindle in the form of a mobile arm tipped with a watch jewel. The latter’s position on the cone reflects the barrel’s state of wind.

The tourbillon of Calibre FB-T.FC-R comprises 67 components assembled within a titanium carriage measuring 16.55 mm in diameter. This tourbillon contributes to earning this movement its chronometer title awarded by the Swiss Official Chronometer Testing Institute (COSC). Although it performs one rotation per minute, this tourbillon does not indicate the seconds, leaving the task to the central sweep-seconds hand.

Hand-sewn from top-quality leather, the strap of the Ferdinand Berthoud Chronomètre FB 1R.6-1 is secured to the wrist by a folding equipped with a safety mechanism as to avoid inadvertent unbuckling of the strap. The watch may also be fitted with a 20 mm pin buckle for those who prefer it.

The Ferdinand Berthoud Chronomètre FB 1R.6-1 is a 20-piece limited edition. Price on request. ferdinandberthoud.ch