Arnold & Son Constant Force Tourbillon 11 Platinum: A tribute to two watchmaking pioneers

Arnold & Son Constant Force Tourbillon 11 Platinum pairs a constant-force tourbillon with a hand-engraved fern-inspired gold dial. Price: CHF 140,600

 The Constant Force Tourbillon 11 Platinum by Arnold & Son draws on the historic relationship between John Arnold and Abraham-Louis Breguet, expressed through a contemporary tourbillon equipped with Arnold & Son’s constant-force mechanism.

Produced in a limited edition of 11 pieces, the watch also reflects Arnold’s Cornish origins through a hand-engraved dial inspired by the fern-covered moors around Tintagel, his birthplace.

The platinum case measures 41.5 mm in diameter and 13.7 mm in thickness, with a rounded profile and a fine bezel framing the domed sapphire crystal. 

Both the front and rear crystals receive anti-reflective coating on both sides, while water resistance is rated to 30 metres / 100 feet.

The solid 18-carat yellow-gold dial is hand-engraved using the “tremblé” technique, in which a burin traces deliberately irregular zigzag patterns across the surface. 

A white opal hour and minute subdial is integrated into the dial, while openings also reveal the constant-force mechanism and its gold bridge.

The true-beat seconds are indicated by the tip of a hand-blued anchor, which also forms part of the constant-force mechanism.

Positioned between the main gear train and the tourbillon, Arnold & Son’s patented constant-force mechanism is designed to maintain a stable supply of energy to the regulating organ throughout the movement’s 100-hour power reserve. 

The system replaces the fusée-and-chain architecture traditionally used in John Arnold’s chronometers and also enables the true-beat seconds display, with the mechanism re-arming its spring at one-second intervals.

The A&S5219 is a manually wound manufacture calibre measuring 33 mm in diameter and 10.48 mm in thickness. It operates at 21,600 vibrations per hour (3 Hz) and contains 35 jewels. 

Its finishing includes a grained and polished main plate, hand-engraved barrel bridge, polished angles, blued and chamfered screws, and a combination of polished, satin-finished and rhodium-plated components.

Through the sapphire case back, the architecture and finishing of the movement can be examined, including the one-minute tourbillon tourbillon and the hand-engraved barrel bridge. 

The tourbillon cage follows the design of the tourbillon in Breguet’s historical regulator, with a rounded, mirror-polished bridge and a variable-inertia balance inspired by John Arnold’s chronometers. 

A further engraved inscription pays tribute to John Arnold and Abraham-Louis Breguet, explicitly recalling their friendship and shared contribution to chronometry.

The Arnold & Son Constant Force Tourbillon 11 Platinum, ref. 1FCBX.Z01A.C0232X, is fitted with a hand-stitched midnight blue alligator leather strap with black alligator lining and a platinum folding clasp. 
Price: CHF 140,600. arnoldandson.com