Craftsmanship

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Components per Grande Complication
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Minimum Apprenticeship
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Component Tolerance
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In-House Production
How a Calibre is Born

From raw brass
to living mechanism.

Every Aurum Tempus calibre follows the same eight-stage process established by Édouard Vallat in 1891. The materials and tools have evolved. The discipline has not.

01

Design & Computation

Each calibre begins with hand-drawn architectural sketches by our head of complications, then translated to 3D CAD toleranced to ±0.001mm. Simulations run for 800 hours of continuous virtual operation before a single component is machined.

02

Alloy Selection & Sourcing

Main plates are milled from specialist German brass alloys. Gear trains use a proprietary copper-beryllium composition developed by Luc Vallat in 1988 for maximum fatigue resistance. Gold chatons are cast on-site from conflict-free sources.

03

CNC & Finishing

Roughed components emerge from our 5-axis CNC lathes, then pass to finisseurs who remove every machining trace by hand. Côtes de Genève stripes, perlage circles, and anglage bevels are applied by eye — each stroke under 40× magnification.

04

Escapement Construction

Our silicon pallet fork and escape wheel are grown in our own clean-room by deep reactive ion etching. The lever geometry is calculated to maximise impulse efficiency — our current escapements achieve 92.4% energy transfer, against the industry average of 86%.

05

First Assembly

A single watchmaker assembles the rough movement from first component to first tick. This takes between three days (Perpetuelle) and fourteen weeks (Grande Complication). No component passes between hands until the movement runs for the first time.

06

Regulation & Chronometry

Movements are tested across six positions over sixteen days. Master regulator Adrien Châtelain adjusts the balance wheel hairspring by fractions of a micron until the movement achieves the Geneva Seal's ±2 seconds per day in all positions. Our current average: ±1.4 seconds.

07

Case Construction

Cases are machined from solid bar stock — never cast. A Perpetuelle case passes through twenty-six individual operations; a Grande Complication case requires eighty-one. Polishing alternates between Zapon lacquer-brushed and mirror surfaces, each transition hand-executed.

08

Final Casing & Certification

The completed movement is cased, timed again for three further days, then presented to the Vallat family's personal quality review — a practice unchanged since 1889. Each piece exits the manufacture with a signed certificate, a movement extract, and a photograph taken the day of completion.

In-House Calibres

The Engines
of Aurum Tempus.

Calibre AT-1889

Manual Wind, Classic

Diameter26.8mm (11¾'')
Thickness3.65mm
Jewels19
Frequency28,800 vph / 4 Hz
Power Reserve72 hours
Accuracy±1.8 s/day
FinishingCôtes de Genève, Perlage
Calibre AT-2241

Flyback Chronograph

Diameter30.0mm (13'')
Thickness7.20mm
Jewels32
Frequency36,000 vph / 5 Hz
Power Reserve65 hours
Accuracy±1.5 s/day
ComplicationFlyback Chronograph
Calibre AT-9600

Grande Complication

Diameter34.0mm (15'')
Thickness11.40mm
Jewels58
Components312 individual parts
Power Reserve54 hours
ComplicationsPerp. Cal., Min. Rep., Tourbillon
Assembly2,400 hours per piece
GUILLOCHÉ HAND ENGRAVED
Dial Finishing

Guilloché — the Engine Turner's Art

Our dials are engraved by hand on a 1920s rose engine lathe — one of only a handful still in regular horological use. Master artisan Claude Morin spends up to forty hours on a single Grande Complication dial, cutting the crosshatch pattern in a single continuous session — any interruption destroys the rhythm of the cuts.

No two dials are identical. The pattern shifts imperceptibly with each rotation of the lathe, meaning your Aurum Tempus is, quite literally, a unique object.

Commission a Bespoke Piece
Case Finishing

Anglage — the Art of the Chamfer

Every metal angle within an Aurum Tempus movement — from the main plate to the finest lever — receives a hand-applied chamfer, polished to a mirror finish under magnification. This is anglage, and it is performed entirely with a pegwood stick charged with diamantine powder.

A Grande Complication movement contains over 1,400 individual chamfered edges. Each one takes between 30 seconds and 8 minutes depending on accessibility. The total anglage time for a Grande Complication: approximately 120 hours.

Explore the Collections
ANGLAGE HAND CHAMFERED
Visit the Manufacture

See the Work
Before You Own It.

We welcome qualified guests to tour the Rue du Rhône manufacture — to watch, to learn, and to choose their piece in person. Visits are arranged by appointment only.

Request a Visit Our Heritage →