New and reviewed: MB&F LM Thunderdome

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MB&F collaborates with Eric Coudray and Kari Voutilainen for this new Legacy Machine – the Thunderdome. Triple axis tourbillon in an LM case designed by Eric Coudray in a movement by Kari Voutilainen and made by MB&F. Interesting collab. We explore in depth.

Three world firsts

  • First-ever collaboration between legends Eric Coudray and Kari Voutilainen.
  • Proprietary new ‘TriAx’ mechanism features 3 axes revolving at different speeds and on different planes, in record-breaking 8 seconds, 12 seconds and 20 seconds.
  • Unique combination of Potter escapement, hemispherical balance and helical hairspring.

MB&F LM Thunderdome

In the presentation in Dubai, Charris Yadigaroglou, MB&F’s Head of Communications told us that the only directive to Eric Coudray was to “make the craziest, most cinematic three-axis tourbillon ever.”

The concept

Eric’s concept was interesting in two aspects. The new TriAx mechanism, as the tourbillon is known, is a triple axis rotating escapement which is deconstructed in such a way that only the essence remains. Instead of the straightforward (if ever a triple axis system is ever straightforward) but cumbersome system that associates one cage to each rotation axis, the TriAx only uses two cages with one axis seemingly to just float in the 3-d space of the tourbillon.

And the second is Eric chose to use an unusual Potter escapement (patent US168582A by Albert H. Potter, filed in 1875), which uses a fixed escape wheel in place of the mobile escape wheel.

Instead of driving the escape wheel, via its pinion, around a fixed fourth wheel, Potter made the escape wheel the fixed wheel, and altered the geometry of the escape lever accordingly. This, he correctly theorised, would allow blindingly fast tourbillon rotational speeds.

The TriAx used in the Thunderdome.

In the TriAx mechanism, the Potter escapement is modified yet further. Instead of a fixed escape wheel with externally oriented teeth, co-axial to the balance, the TriAx uses a fixed escape wheel with inverted teeth, co-planar to the lever fork. This method has never been used in a multi-axis mechanism.

As a result, the innermost structure completes one turn in 8 seconds, the intermediate cage rotating once every 12 seconds, and the outermost cage making one full rotation every 20 seconds.

An additional advantage of the Potter escapement is that it frees up more space for the balance and hairspring, allowing to better admire another completely novel development: the balance is hemispherical shaped, wrapping around the helical hairspring. This hemispherical balance is a custom solution to allow for the largest possible balance in combination with a cylindrical hairspring.

The adjustment of the triple axis tourbillon presents significant challenges to the standard Witchi machines used. Even standard laser measuring instruments have difficulty with the continuously shifting balance and its rotating cages. In the development of the TriAx, MB&F furthered the application of this laser technology by shifting the beam frequency to infra-red. This allows the system to take discrete readings at specific intervals and for proper adjustment of the mechanism.

The case, dial and hands

The case is the usual shape of the Legacy Machine, which is designed to be as conventional as Max Büsser’s imagination will allow. The case itself is round and sports sensuous curves. Lugs curve from the sides and presents curved spring bars for a “well dressed” look. The bezel melds into the lugs and a small lip separates it from the case middle and the case back. The crown is set at 2 o’clock, and is the usual flat ribbed crown in an MB&F.

The case diameter is 44mm, but a huge dome in sapphire glass covers the dial, as the dial proper which houses the hour and minute sub-dial set at an angle to the base dial, and the enormous, curved two armed bridge which carries the TriAx tourbillon in suspension. To cover the entire mechanism which protrudes from the base dial, the glass is almost hemispherical and rises to a height of 22.2 mm.

The dome rises 22.2mm above the case, and hence the name, “Thunderdome”.

The TriAx tourbillon is presented in clear view, and it is indeed a mesmerising view, with the animations of the fast turning triple axis mechanism providing visual stimulation like no other watch. It is difficult to tear one’s eyes off the mechanism.

The hour minute subdial is in the usual LM style, which is slightly convex dome shape, with a stretched membrane. The base dial is light-blue guilloché which looks almost like it is radiating light from within. This base dial is created in Kari’s dial facility in Comblémine.

The movement

The movement is where the magic happens. Of course! This is a Coudray creation afterall, and Eric is known for spectacular theaterics. From the first Jaeger-LeCoultre Gyrotourbillon to the Gyrotourbillon 2 to fixing the Cabestan Winch and creating the Cabestan Triple Axis to being the brains behind the multi-axis tourbillons of Cecil Purnell, his work has always fascinated us.

The three axes rotating at different speeds on different planes present interesting challenges. The innermost axis makes one complete turn in 8 seconds. The next axis of rotation is canted at right angles to the first, and makes one complete turn in 12 seconds. The outermost axis of rotation is canted at right angles to the second, and makes one complete turn in 20 seconds. This is the fastest combined rotation in the category of multi-axis regulating mechanisms.

Additionally, the last axis of rotation is eccentric relative to the other two, such that the final motion of the balance wheel, when viewed in isolation, is most precisely described as an orbital tri-axial rotation.

The TriAx design is unique in that it combines key elements of both the karrusel and tourbillon. The karrusel uses a split-train energy transmission system and the tourbillon is based on a fixed wheel to enable the power flow from the barrel directly to the cage. It uses both these features, and is a unique solution to the triple axis tourbillon that we have not seen before.

From the case back, the bridge layout and finishing is the work of Kari Voutilainen’s team. The task may seem straightforward compared to technical development, it almost as complex and challenging. The complex and delicate relationship between the 413 components of the TriAx makes every micro-adjustment an exercise in mechanical reconfiguration. With a movement diameter of only 35mm, there is far less margin for error. A bridge that is even 1mm too wide, or a pinion moved just a few micrometres to either side, would immediately stand out, glaringly out of place.

Movement finishing is to the usual high levels one expects from Voutilainen. The bridges feature many sharp inward and outward angles which can only be executed by hand. Visually, the softly luminous Geneva waves characteristic of Voutilainen are applied by hand, as are the frosting and engraving on the power-reserve indication provides a light play which is a pleasure to observe. The ratchet wheels are finished in a proprietary technique that imparts a sheen that appears almost uniformly sandblasted, but reflects direct light in deeply curved sinusoidal waves.

Concluding thoughts

What can we say? The LM Thunderdome is spectacular. The base dial, radiating in its brilliant blue hue and guillochéd surface is beautiful. The way the tourbillon, rising out from that base, and suspended by the curvaceous bridge, spinning around furiously on all its three axes, is truly mesmerising. The huge dome, initially seems to be too large and cumbersome, in practice and in wear seem to almost disappear, and after a while, we never noticed it at all.

The LM Thunderdome is launched in two limited editions:

  • 33 pieces in platinum 950, with a light-blue guilloché dial plate;
  • 10 pieces in tantalum commemorating the 40th anniversary of Asia-Pacific retail group The Hour Glass, with five pieces bearing a dark-blue guilloché dial and five pieces with an inlaid aventurine dial.

MB&F LM Thunderdome – Technical Specifications

Official press photograph from MB&F.

Two Limited Editions : – Limited edition of 33 pieces in platinum 950, with light-blue guilloché dial; – Limited edition of 10 pieces in tantalum for The Hour Glass (5 pieces with an aventurine dial and 5 pieces with a darkblue guilloché dial).
Engine Movement developed for MB&F by Eric Coudray and Kari Voutilainen.
Regulating mechanism featuring 3 fast rotation axes revolving at different speeds and on different planes. The rotation speeds of the axes starting from the centre are respectively 8 seconds, 12 seconds and 20 seconds. The combined weight of the multi-axis mechanism is nearly 1g.
Manual winding with three mainspring barrels.
Bespoke hemispherical 10mm balance wheel with traditional regulating screws and helical hairspring, visible on top of the movement. Superlative hand finishing throughout respecting 19th-century style; bevelled internal angles highlighting hand craft; polished bevels; Geneva waves; hand-made engravings. Power reserve: 45 hours Balance frequency: 3 Hz / 21,600bph Number of components: 413 Number of jewels: 63
Functions & indications Hours and minutes displayed on a 58° vertically tilted dial Power reserve indicator on the back of the movement
Case Material: launch edition in platinum 950 and The Hour Glass editions in tantalum Dimensions: 44mm × 22.2 mm Number of components: 20 Water resistance: 30m / 90’ / 3ATM
Sapphire crystals Sapphire crystals on top and display back treated with anti-reflective coating on both faces.
Strap & buckle Blue hand-stitched alligator strap with platinum or tantalum folding buckle matching the case.


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