Arnold & Son Constant Force Tourbillon 11 Review

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The contemporary watchmaking landscape contains precious few timepieces that genuinely merit the descriptor “architecture.” Most watches, however refined in their execution, remain exercises in variation on established themes. The Constant Force Tourbillon 11 from Arnold & Son stands apart. This yellow gold chronometer represents a deliberate articulation of mechanical philosophy, its architecture reflecting not the fashions of the present moment but rather the principles that governed the birth of precision timekeeping two centuries ago.

To understand this watch fully requires stepping back from the present into the final decades of the eighteenth century. Arnold & Son, though reconstituted in 1995 by horological scholar Eric A. Loth as a tribute to British watchmaking tradition, traces its spiritual lineage to John Arnold, the Bodmin-born horologist whose innovations fundamentally transformed the science of timekeeping. Arnold’s contributions extended far beyond any single complication. He brought the term “chronometer” into its modern sense, meaning a precision timekeeper whose design possessed both practical reliability and genuine accuracy. His detached escapement, temperature-compensating balance design, and pioneering work with balance springs established the technical foundations upon which modern mechanical watchmaking rests.

Arnold & Son Constant Force Tourbillon 11

Yet the Constant Force Tourbillon 11 honours not only John Arnold alone. Its genesis lies in a friendship that transcended the political upheavals of the French Revolution: the relationship between Arnold and Abraham-Louis Breguet. Between 1789 and 1791, during Breguet’s sojourns to London, these two giants of the Age of Enlightenment exchanged views on the principles of chronometric regulation. Arnold possessed the ability to conceive mechanisms of stunning simplicity that could be produced in quantity without sacrificing precision. Breguet, conversely, brought to watchmaking an understanding of complex kinematics and an aesthetic sensibility that elevated horology to an art form.

The fruits of their intellectual exchange would prove profound. Where Arnold concentrated on perfecting his detent escapement and developing sophisticated balance assemblies to serve his proto-industrial approach to chronometer manufacture for the Admiralty, Breguet seized upon their conversations to develop a revolutionary regulating mechanism. Working in Switzerland during his exile from 1792 onwards, he conceived the tourbillon, a rotating carriage designed to average the effects of positional error upon the balance and hairspring. Patented on 26 June 1801, the 7 Messidor Year IX in the Revolutionary calendar still in force, this mechanism would reshape horological possibility.

To honour Arnold‘s memory after his death in 1799, Breguet constructed his first functional tourbillon not in isolation but rather incorporated into one of Arnold’s own marine chronometers. The dedication engraved upon it read: “The first tourbillon regulator by Breguet incorporated in one of the first works of Arnold. Breguet’s homage to the revered memory of Arnold. Presented to his son in the year 1808.” That instrument now resides in the British Museum, and the Constant Force Tourbillon 11 draws its inspiration directly from this historical achievement.

The Dial: Enamel as a Window into Chronometric History

Arnold & Son has elected to present the Constant Force Tourbillon 11 with a white Grand Feu enamel dial affixed to an 18-carat yellow gold base. The choice of white enamel carries historical significance. It evokes the appearance of the ship’s chronometer dials that John Arnold supplied to naval officers operating from his London boutique. Grand Feu enamel, that most demanding of dial techniques, involves the heating of powdered materials to temperatures exceeding 800 degrees Celsius. The artisan fires the enamel multiple times to achieve the requisite thickness, then carefully laps the surface to ensure smoothness and uniformity. Should imperfections emerge (cracks or discolorations) the piece must be discarded entirely, for Grand Feu accepts no compromise. A final application of translucent enamel, fired once more in the kiln, imparts depth and permanence to the surface. This process yields the characteristic “Grand Feu” hue, achieved through true vitrification rather than superficial coating.

The dial’s layout functions as a technical presentation of the watch’s primary complication. The constant force mechanism, rendered in 18-carat yellow gold, occupies the dial surface and rotates over a span of precisely one minute. This bridge stands in yellow gold rather than the steel typical of such mechanism, creating a visual continuity between the visible complication and the yellow gold case that houses the entire movement. The secondary dial for the hours employs white opal, presented in a concave configuration, a distinctive stylistic choice that affords greater visual prominence and enhanced readability for the black transfer Roman numerals. This marks the first instance in which Arnold & Son has recessed the opal subdial in such fashion, demonstrating that even within the bounds of historical inspiration, the manufacture remains committed to genuine refinement rather than slavish duplication.

The constant force mechanism itself performs a function of considerable importance to chronometric regularity. The barrel delivers power with unequal torque: strongest when freshly wound, it gradually diminishes throughout the power reserve. The constant force mechanism smooths this delivery, ensuring that the balance and hairspring within the tourbillon carriage receive uniform energy regardless of the barrel’s state of wind. Rather than employing a fusee and chain, as John Arnold himself utilised in his marine chronometers, the designers of this calibre have incorporated a patented constant force system that not only delivers stable torque but also enables what the watch world terms “dead-beat seconds” – the distinctive jumping advance of a seconds hand, with each jump spanning precisely one second.

In the case of the Constant Force Tourbillon 11, the dead-beat seconds find expression through an elegantly conceived detail: the flame-blued anchor that serves as the structural bridge for the constant force mechanism itself. Rather than employ a conventional seconds hand, the tip of this anchor demarcates the passage of each second. This approach speaks to the design philosophy that has animated Arnold & Son‘s thinking: architecture over ornamentation, where every component serves both functional and visual purpose.

The Movement: A Chronometric Philosophy in Metal

The A&S5219 calibre represents the intellectual labour of the La Chaux-de-Fonds manufacture, developed specifically to the requirements of the Constant Force Tourbillon 11. To maintain historical fidelity, the calibre remains entirely hand-wound. This decision reflects a particular philosophy regarding the relationship between watchmaker and watch. An automatic rotor introduces complexity and requires the watchmaker to trust in the wearer’s activity level to maintain adequate power reserve. A hand-wound movement places the responsibility for energy management upon the owner, creating a more intimate relationship with the timepiece.

The calibre incorporates two identical barrels mounted in series, a configuration that yields a 100-hour power reserve. It is a specification of considerable achievement in the realm of mechanical watches. The barrels function through an alternating sequence, with the second barrel activating only when the torque output of the first falls below optimal levels. This arrangement ensures that the constant force mechanism receives appropriately regulated energy across the entire 100-hour duration, thereby maintaining the isochronism that Abraham-Louis Breguet’s tourbillon was designed to support.

The movement’s beating rate stands at 3 Hz (21,600 vibrations per hour), a frequency that represents a careful equilibrium between chronometric regulation and energy consumption. Within a 33-millimetre diameter and 10.48-millimetre thickness, the manufacture has assembled 35 jewels distributed throughout the gear train and escapement assembly.

The architectural inspiration for the A&S5219 derives directly from the tourbillon chronometer that now resides in the British Museum. Yet contemporary watchmaking cannot simply reproduce eighteenth-century mechanics; instead, the manufacture has interpreted historical principles through modern materials and manufacturing capability. The tourbillon carriage itself exhibits the refined engineering characteristic of contemporary haute horlogerie. Rendered with a polished carriage plate and mirror-finished elements, the carriage appears almost ethereal when viewed through the exhibition case back. The pallet bridge exhibits satin finishing, whilst the stud-holder receives full mirror polish. The balance wheel, finished in rhodium, undergoes the standard regulations of precision timekeeping, with inertia blocks inspired by the sophisticated oscillators that John Arnold developed for his marine chronometers.

The variable inertia balance employed within the tourbillon carriage represents a technical decision that echoes Arnold‘s own thinking. Rather than employing a simple simple-harmonic oscillator, a balance with adjustable inertia blocks allows the watchmaker to fine-tune chronometric performance through the redistribution of mass. This approach offers greater flexibility than fixed-inertia designs, permitting adjustment to accommodate variations in hairspring behaviour or environmental factors.

Of particular interest stands the retaining spring of the tourbillon assembly, fashioned as a T-shaped component inspired by the “pare-chute” shock protection system that Breguet developed and integrated into his original tourbillon mechanism. The pare-chute concept represents one of Breguet’s most enduring contributions to horological practice, employing a specific spring configuration to protect the delicate balance assembly during shocks or drops. Arnold & Son has incorporated this historical reference as an active protection system rather than merely aesthetic homage.

The escapement selected for the A&S5219 represents a pragmatic divergence from the historical original. Whereas the British Museum’s Breguet-Arnold tourbillon employs a detent escapement (characteristic of marine chronometers), the contemporary calibre utilises a Swiss lever escapement. The detent escapement, whilst capable of extraordinary precision, displays heightened sensitivity to shocks and requires careful handling. The lever escapement, more robust and more resistant to positional error through shocks, remains the industry standard for a reason. This decision reflects the philosophy that innovation need not require the wholesale abandonment of proven solutions, but rather their intelligent adaptation.

The finishing programme applied to the A&S5219 distinguishes this movement within the crowded landscape of contemporary complications. The mainplate receives a distinctive 3N golden finish, with surfaces grained and angles polished in the traditional manner. The barrel bridge, similarly finished in golden tone, receives hand-engraved inscriptions and features the commemorative plate that Arnold & Son has created to mark this edition. The inscription reads: “To the revered memory of John Arnold and Abraham-Louis Breguet. Friends in their time, legendary watchmakers always.” These words articulate the historical purpose of this limited edition of eleven timepieces.

The tourbillon bridge exhibits polished angles and grained surfaces in keeping with movement decoration standards. The screws throughout the movement receive blue tempering at the arms and chamfering at the shoulders, with heads finished to a mirror polish. The constant force bridge, rendered entirely in 18-carat yellow gold, presents polished bevel work with a satin-finished flat surface and polished edges. The flame-blued constant force carriage lower bridge, serving as the structural support for the seconds indication, exhibits mirror polish with polished angles.

This catalogue of finishing approaches, whilst potentially appearing excessive in enumeration, serves a fundamental purpose in the context of a complicated movement displayed through an exhibition case back. The eye naturally seeks texture and visual variation. A movement finished entirely in a single manner becomes visually monotonous. The varied surfaces, grained, polished, satin-finished, flame-blued, create visual interest whilst simultaneously reflecting the skilled labour that assembled these components. This represents honest finishing rather than the application of surface texture as mere ornamentation.

The Case: Yellow Gold as Historical Reference

Arnold & Son has enclosed the A&S5219 movement within a 41.5-millimetre diameter case of 18-carat yellow gold. This material choice reflects deliberate historical consciousness. John Arnold favoured yellow gold for his most prestigious pocket watches, particularly those created for distinguished patrons. The colour of yellow gold, that particular warm luminosity created by the alloying of pure gold with copper, possesses an aesthetic quality that stainless steel simply cannot match. In the context of a watch inspired by Arnold’s own practices, the choice becomes not merely material specification but rather a commitment to historical authenticity.

The case itself measures 13.7 millimetres in depth, a specification that reflects considered proportions. The 41.5-millimetre diameter, positioned at the contemporary boundary between wristwatch and large dress watch, receives tempered by a curved case middle that reduces the perceived profile. Were the sides of the case rendered straight and perpendicular to the dial plane, the watch would appear thicker and more blocky. The curve, subtle but present, imparts a sense of refinement and ensures that the watch sits elegantly upon the wrist without appearing monolithic.

The crystal system comprises a pair of sapphire elements. The dial-facing crystal exhibits a subtle dome rather than the flat sapphires characteristic of much contemporary watchmaking. This dome, gentle in its curvature, provides a slight magnification effect upon the dial whilst creating a more sophisticated visual appearance than a flat crystal would permit. The crystal receives anti-reflective coating upon both surfaces, a specification necessary for visibility in bright light conditions. The exhibition case back employs an identical sapphire crystal, permitting unobstructed viewing of the movement architecture whilst maintaining structural integrity and protecting against dust ingress.

Water resistance stands rated at 3 bar (30 metres or 100 feet), a specification that places the Constant Force Tourbillon 11 firmly within the dress watch category. This limitation reflects the nature of the movement architecture. The two barrels, the constant force mechanism, and the tourbillon carriage all require precise spacing and alignment. Pressurising such a movement would necessitate engineering compromises that would detract from its primary function, which consists not of aquatic protection but rather of chronometric excellence. The specification proves entirely appropriate to the watch’s intended role.

The case back features another crystal permitting viewing of the movement without removing an entire solid back and potentially disturbing the delicate chronometric assemblies. This approach, characteristic of higher-quality watchmaking, reflects respect for the integrity of the movement without compromising the joy of the viewer.

Arnold & Son presents the Constant Force Tourbillon 11 upon an alligator leather strap of midnight blue, furnished with black alligator lining to enhance durability and comfort. The buckle consists of 18-carat yellow gold rendered as a simple pin fastener bearing the Arnold & Son monogram. This strap system, constructed from genuine alligator leather by established specialists, demonstrates the thought extended to every component of the timepiece.

The Architecture of Aspiration

The Constant Force Tourbillon 11 occupies a distinctive position within contemporary watchmaking. It does not attempt to revolutionise horological practice nor to introduce previously unconceived complications. Rather, it represents a considered interpretation of historical principles through contemporary manufacturing capability, executed with the technical competence and material integrity that characterise the finest watchmaking. The 100-hour power reserve, the constant force mechanism, and the tourbillon carriage all function in concert to deliver the chronometric stability that motivated John Arnold and Abraham-Louis Breguet during their intellectual exchanges across the English Channel.

The choice of materials, 18-carat yellow gold for case, dial base, and the constant force bridge, reveals a confidence in aesthetic choice that sidesteps current fashion. The Grand Feu enamel dial, created through processes unchanged since the eighteenth century, speaks to a commitment to craft tradition. The hand-wound movement, the open case back, and the decorative finishing all reinforce the fundamental proposition: that watchmaking of the highest order involves the intelligent application of proven solutions rather than novelty for its own sake.

Limited to eleven examples, a production number that directly references John Arnold’s marine chronometer number 11, the Constant Force Tourbillon 11 presents itself as a watch created for individuals who possess sufficient horological knowledge to perceive its merits without requiring marketing explanation. The constant force mechanism, visible on the dial, requires no rotation of the wrist to appreciate its function. The tourbillon, presented through a perfectly transparent case back, reveals the calibre’s entire architecture without compromise or obstruction.

At a Swiss retail price of €155,000 incl. VAT, this timepiece commands the investment befitting a movement of such complexity and case material of such integrity. Within the contemporary landscape of constantly revised references, seasonal colour variations, and limited editions defined by production numbers in the thousands, Arnold & Son’s commitment to producing only eleven examples of this chronometer possesses a quiet dignity. Ownership becomes not the acquisition of a commodity watch but rather stewardship of a horological instrument created to commemorate two of watchmaking’s most influential figures and the intellectual collaboration that shaped modern timekeeping science.

The Constant Force Tourbillon 11 succeeds because it recognises that great watchmaking operates within constraints rather than in rebellion against them. The 100-hour power reserve requires two barrels. The constant force complication demands precise engineering and careful finishing. The tourbillon, rather than serving as marketing decoration, performs its intended function of regulating positional error. Every component, every surface, every architectural decision contributes to a coherent whole. In an era of technical exuberance and design novelty, such clarity of purpose represents an achievement of considerable distinction. It is one of my favourite watches this year and I love it! Exceptional!

Arnold & Son Constant Force Tourbillon 11 Technical Specifications

Reference 1FCBJ.E01A.C246J – €155,000 incl. VAT, Limited edition 11 timepieces

Functions

Hours, minutes, true-beat seconds

Movement

Calibre A&S5219 hand-wound mechanical movement, constant force, one-minute tourbillon
Jewels: 35
Diameter: 33 mm
Thickness: 10.48 mm
Power reserve: 100 hours
Frequency: 3 Hz / 21,600 vph
Finishes mainplate:
- 3N golden finish, grained, polished angles
- barrel bridge: 3N golden finish, grained, polished angles, stretched edges, hand-engraved
- tourbillon bridge: golden finish, grained, polished angles, stretched edges, satin-finished Durnico steel retaining spring
- screws: blued, chamfered, mirror-polished heads
- tourbillon: mirror-polished carriage plate, satin-finished pallet bridge, mirror-polished stud-holder, rhodium-finished balance, polished and rounded-off carriage bridge
- constant force bridge: 18-carat yellow gold (3N), polished bevel, satin-finished flat surface, polished angles
- constant force carriage lower bridge: flame-blued, mirror-polished, polished angles
Engraved plate: To the revered memory of John Arnold and Abraham-Louis Breguet. Friends in their time, legendary watchmakers always.