Arnold & Son Unveils Platinum Constant Force Tourbillon
Arnold & Son has unveiled the Constant Force Tourbillon 11 Platinum Edition, a limited run of 11 pieces priced at CHF 140,600 marking the brand’s 260th anniversary. The timepiece pays homage to founder John Arnold through detailed hand engraving and a mechanical complication that traces its lineage directly to a historic 1808 gift from Abraham-Louis Breguet.
Cornish Inspiration on a Golden Dial
The watch features an 18-carat yellow gold dial hand-engraved with a “tremblé” fern pattern. Arnold & Son artisans use a burin engraver to craft the irregular zigzag motifs, creating an organic design inspired by the wild moors around Tintagel in Cornwall—John Arnold’s birthplace and the setting for Arthurian legend. The engraving captures the movement of ferns bending in coastal winds, linking the watchmaker’s heritage to the setting that shaped his early years.
A white opal subdial displays hours and minutes, while the constant force mechanism sits beneath an 18-carat gold bridge. The tourbillon cage rotates in precise one-second increments, echoing the demands of marine chronometry when seconds mattered for calculating longitude at sea.
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Platinum Case and Construction
The classically proportioned case measures 41.5 mm in diameter, crafted from platinum for a slender appearance on the wrist. A domed sapphire crystal with anti-reflective coating protects the dial, while a sapphire caseback reveals the manual-winding A&S5219 caliber. Water resistance stands at 3 bar, and the watch arrives on a hand-stitched midnight blue alligator leather strap with a platinum folding clasp.
The Constant Force Mechanism
Arnold & Son’s patented constant force mechanism sits between the main gear train and tourbillon to ensure consistent energy delivery throughout the 100-hour power reserve. The system eliminates torque variations that could disrupt the balance wheel’s oscillation, re-arming a finely adjusted spring second by second for stable transmission to the tourbillon cage. This replaces the fusée-and-chain system John Arnold used in his chronometers.
The mechanism also produces a true-beat seconds display. Instead of a conventional seconds hand, the blued anchor tip indicates seconds while simultaneously serving as a structural bridge for the constant force system.
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A Watchmaking Friendship Revived
The sapphire caseback exposes the A&S5219 caliber, its architecture inspired by the first tourbillon regulator Breguet created. That historic piece, now housed at the British Museum, was based on Arnold’s No. 11 chronometer and given to John Roger Arnold in 1808. The tourbillon cage faithfully reproduces the original design, featuring a mirror-polished linear cage bridge and variable-inertia balance drawing from Arnold’s most accomplished chronometers.
Finishing details mirror the original tourbillon, with hand-engraved inscriptions on the barrel bridge. An engraved plate bears the tribute: “To the revered memory of John Arnold and Abraham-Louis Breguet. Friends in their time, legendary watchmakers always.”
The Constant Force Tourbillon 11 Platinum Edition serves as the final chapter in Arnold & Son’s Constant Force 11 collection, which launched with a gold model. Technical specifications include a 33-jewel movement, 3 Hz frequency (21,600 vph), 13.7 mm case thickness, and movement dimensions of 33 mm by 6.3 mm. The reference number is 11CFTF01P0021.PP, with the platinum case standing 13.7 mm tall.
