In keeping with the purest horological traditions, the 188 components of the Manufacture Calibre MB M18.69 are entirely hand-decorated by expert craftsmen and women using artisanal finishings such as circular graining, mirror-polishing, and beveling. In addition, the movement also counts 420 inner angles that require expertise and passion to complete.
The new skeletonized Exo Tourbillon movement’s architecture
The original patented Exo Tourbillon complication was developed in-house at the Montblanc Manufacture in Villeret and required three years of development. This new version of the in-house manual-winding movement — the Calibre MB M18.69 — took the Montblanc engineers a further 18 months to develop due to the complexity of its skeletonization. The Manufacture movement Calibre MB M18.69, with its 188 components, was completely rethought in terms of aesthetics, geometry, and stability to reveal the beauty of its mechanism while increasing its performance.
The movement features a three-dimensional construction on different levels, bringing a whole new level of suspension to the timepiece. This is achieved with five pillars that support the main plate on the top, and the barrel and going train bridges on the bottom. It is completed on the front by the Exo Tourbillon balance wheel and the off-centered domed hour and minute dial at 12 o’clock. The main plate and bridges have been completely open-worked, making them visible on both sides of the watch. The barrel drum has also been opened to reveal the spring.
The resulting timepiece creates a composition of pure lines where watchmaking artisanal know-how meets technology, drawing attention to the Exo Tourbillon and the skeletonized movement from top to bottom. Very rarely can we observe a whole movement working from every angle and get a 360-degree view. Each of the movement’s tiny components is meticulously decorated by hand, following traditional techniques that create a bright and airy timepiece. Due to the level of skeletonization and decoration, assembly requires particular dexterity and care in order to avoid scratches on the beveled components.
The Montblanc Manufacture in Villeret is a very special place that possesses the know-how to produce a movement from A to Z, making all the main components in-house, such as the plates and bridges in German-silver (“Maillechort”) with traditional decoration, and it also manufactures the full regulating organ in-house, including the hairspring.
Artisanal hand-finishing movement decoration
The 188 components of the Manufacture movement Calibre MB M18.69 are entirely decorated in the Montblanc Manufacture in Villeret with traditional horological finishings such as circular graining, mirror-polishing and beveling with inner angles. In total, the movement has more than 420 inner angles that take over two weeks to be decorated by Montblanc’s watch experts. This high-end, artisanal finishing, where the angles of tiny components are beveled by hand to accentuate the play of light, is a very ancient and authentic watchmaking art. There are different types of angles, but the inner angles ( 90° < to <180°), where the meeting point of two chamfers creates a sharp intersection, are very difficult to achieve. It is impossible to make these with a machine and each artisan develops his/her own technique and tools in order to work each tiny component. In Villeret, artisans often use the stems of mountain flowers, such as gentian, a soft local wood, that is used to apply the polished diamond paste to specific components in order to create the distinctive final shiny effect. This kind of decoration takes time and patience and it takes years of experience to master this precise and regular work.
The new 18K rose gold case & the 18K gold and Grand Feu enamel dial
Inspired by the three-dimensional bridge configuration, the construction of the case, with its domed sapphire crystal on the front, has been built around the movement. The external part of the movement’s main plate has been fixed inside the sides of the case giving an impression of complete suspension. The 44.8 mm case comes in 18 K rose gold and features a sapphire crystal on both sides of the watch, revealing the full beauty of the hand-finished manually-wound Calibre MB M18.69. It also provides a totally transparent view of the Star Legacy Exo Tourbillon Skeleton from front to back.
The off-centered dial, placed on the movement and located at 12 o’clock, is made of 18 K gold and Grand Feu enamel, a rare technical feat that provides an artisanal and traditional touch. 18K rose gold leaf hour and minute hands complete the overall aesthetic.
The timepiece comes fitted with a brown Sfumato alligator leather strap coming from the Pelletteria in Florence, Italy, and is equipped with a triple folding clasp with security pushers, offering a secure grip.
The ”Exo Tourbillon” by Montblanc, patented since 2012
The “Exo” is derived from the Greek for external or outside and refers to the large balance wheel with screws, which is positioned outside of the tourbillon’s rotating cage. This particular patented construction of the Suspended Exo Tourbillon allows the watchmakers at the Montblanc Manufacture in Villeret to have a large and impressive balance wheel and eliminates the need to increase the size of the movement or the case. The massive balance wheel is raised 4.15 mm higher than the dial and appears to be floating above it. This suspended position has been made possible thanks to a tourbillon bridge with only one stainless steel arm which is curved and mirrors the domed hour circle at 12 o’clock. It creates a three-dimensional look and a new fine watchmaking aesthetic. Due to its asymmetric construction, the alignment of the Exo Tourbillon bridge, with its solitary arm, represents a horological challenge and demands skill and dexterity to complete. The complexity of the patented Exo Tourbillon comes from the dimensions of the long axis that needs to be precise with a concentricity tolerance with a diameter of 0.01 mm, along with the complication construction itself, which requires that the balance’s axis must be perfectly perpendicular to the movement. This technical aspect has been particularly worked on this new model as the tourbillon bridge and the seconds counter are made of one piece, leading to a highly stable construction that is easier to align. Then, a deviation of 5 microns (0.005 mm) at the base of the bridge can result in a deviation at the centre of only 5 microns (0.005 mm) à ratio of 1
Montblanc Star Legacy Exo Tourbillon Skeleton Limited Edition 8
MOVEMENT Montblanc Manufacture open-worked Calibre MB M18.69
Type of movement Mechanical movement with manual winding mechanism, patented one-minute Suspended Exo Tourbillon
Dimensions Diameter = 41.95 mm; height = 6.45 mm
No. of components 188
No. of rubies 19
Power reserve Approx. 50 hours
Balance Screw balance, diameter = 14.5 mm; moment of inertia = 59 mgcm²
Frequency 18,000 A/h (2.5 Hz)
Hairspring With Phillips terminal curve
Plate Open-worked rhodium-plated German-silver, stretched stripes on both sides, hand-chamfered edges
Displays Off-centered hours and minutes, small second at 6 o’clock
Patented Exo Tourbillon (one revolution per minute to indicate the seconds) with one arm-bridge at 6 o’clock, mirror-polished Exo Tourbillon cage
Bridges Open-worked rhodium-plated German-silver, stretched stripes on both sides, hand-chamfered edges
Going-train Gold-plated, circular grained, chamfered, diamond hubs on both sides
Barrel Mirror-polished open-worked ratchet, circular-graining inside the mirror-polished winding pawl shaped with the Minerva arrow
Case 18 K rose gold, polished case
Crystal Scratch-resistant, domed anti-reflective sapphire crystal on both sides
Back 18 K rose gold with inset pane of sapphire crystal
Dimensions Diameter = 44.8 mm / Height = 15.01 mm
Water resistance 3 bar (30 m)
Crown 18 K rose gold with Montblanc emblem in mother-of-pearl
Dial Domed 18 K gold dial with ivory “Grand Feu” enamel, black Arabic numerals, 18 K rose gold leaf hour and minute-hands
Wristband Brown Sfumato alligator leather strap coming from the Pelletteria in Florence, Italy with an 18 K rose gold triple folding clasp
Limited Edition 8