Naissance d’une Montre 4: Inside Bonniksen’s Radical Case for “Le Carrousel”

As rotating regulating devices invented to fight gravity’s slow corruption of the balance spring, the carrousel and the tourbillon are widely treated as siblings.

However, as Maximin Chapuis, Bonniksen’s master watchmaker, will tell you, they are not the same animal at all: “In a carrousel, there is absolutely nothing fixed.” That means: No wheel locked to the plate; no anchor point; just two mobiles spinning in relative motion inside a cage that is itself in motion, creating a differential velocity problem that has defeated most watchmakers for 130 years.
 

Until now, there has been exactly one manufacturer in the world that has solved this conundrum. And Blancpain did it using a flying carrousel supported on a single pivot…simple. Bonniksen’s, however, will be fully pivoted, top and bottom, which means more components, more architecture, and exponentially more complexity.

The pivoted carrousel was Bahne Bonniksen’s own final obsession. The Danish-British watchmaker invented the complication in 1894, founded the British Watch and Clock Makers’ Guild in 1907, and never finished his ultimate version of the mechanism.
 

Jason Chevrolat, 36, is an entrepreneur, consultant, and watch expert who, before founding Bonniksen, which was officially revived as a brand in April 2026, as its sole investor, built and led multiple business units – a career grounded in dual master’s degrees in entrepreneurship from ESC Troyes and engineering from the École Polytechnique de Paris Sud.

Beside him, Maximin Chapuis, 30, brings a watchmaker’s pedigree earned on the bench rather than in the classroom: trained in the Vallée de Joux, then refined at the Paris school of watchmaking under Michel Boulanger, and a professor at WOSTEP, the institution that has trained the industry’s finest for decades. Together, they intend to complete what Bonniksen left behind.
 

“We are making a proposal to continue the work of the inventor of the carrousel,” Chapuis says, without a trace of false modesty. The cage rotates once every 30 seconds – a specification that required running algorithms to find viable gear ratios, since the differential equations governing a carrousel’s gear train are categorically more complex than those of a tourbillon.

The Bonniksen workshop in La Chaux-de-Fonds stretches across 130 square meters. Around 30% of the tools were accumulated personally by Chapuis over ten years; the rest – heavy mills, watchmakers’ benches – arrived in the last 18 months. None of the machines use CNC.

In fact, all of them are at least 50 years old because, below that threshold, vintage precision equipment loses the calibration stability required for manual production to micron tolerances. Each one has been fully disassembled, cleaned thread by thread, and rebuilt by Chapuis himself. The machine park is, he notes, identical in type to Greubel Forsey’s handmade atelier, except they are six people.