An outer hull of sapphire crystal and precious metal, curved and bubbled and fitted together in three parts, is sealed with a proprietary combination of patented three-dimensional gasket and high-tech compound bonding process. Two fully independent cantilevered balances channel data into a differential that turns two heartbeats into one coherent time-pulse. Ultra-precise conical gears efficiently turn the engine’s energy and information current through a 90° angle to feed the time display on a sapphire crystal dial, marked with Super-LumiNova.
On the reverse, co-axial beneath each of the balances are propellers: twin turbines that spin as an element of pure visual interest, waiting for someone to begin a new type of exploration. HM9-SV takes us to the depths of the ocean – the last realm on Earth that still holds a wealth of untold secrets.
Externally, the laws of fluid dynamics remain dominant in its design, although the hydro-governed objectives allow HM9-SV to take a more lenient approach to the sharp inward angles and parabolic curves of the previous Flow versions. From a technical standpoint, the reworked dimensions were necessary to account for the differences in material properties of sapphire crystal; although extremely hard, sapphire can fracture sharply under pressure whereas a metal would merely deform. The smoother lines of HM9-SV minimise potential areas of mechanical vulnerability.
Its three-dimensional assemblage of wheels, gears, plates and bridges takes unexpected forms to inhabit the dynamic outer case, a beating union of mechanical viscera and endoskeleton in a crystalline body.
A traditional balance frequency of 2.5Hz (18,000vph) may seem anachronistic in a modern timekeeper, but the sensitivity to shock associated with a lower beat rate is compensated for by having two balances instead of one. Statistically speaking, two identically calibrated systems offer a better averaged reading than one system on its own which may deliver anomalous results for any number of reasons.
To further reduce sensitivity to shocks, the HM9-SV editions feature a new shock-absorbing system: helicoidal springs placed between the movement and the case. The springs are crafted by laser from a solid tube of polished stainless steel, offering excellent elasticity and limited lateral displacement.
Performing the task of averaging the time measurement from the twin balances of the HM9 engine is a planetary differential, the gearbox of the movement, which then delivers a final reading to be displayed on the perpendicularly oriented dial. every aspect of the engine is open to discovery; the eye can follow the interplay of components from barrel to balance, from differential to dial.
In order to seal the sapphire crystal exterior components into one watertight case, The 3-D gasket remains in HM9-SV, but the sapphire crystals are fused with the metallic frame thanks to a high-tech bonding compound, mastered via an in-house process involving a vacuum and high temperature. The result is a seal resistant to 3ATM (30m) of water pressure, despite practically invisible seams between the sapphire components and the minimalistic frame in 18K gold.
HM9 Sapphire Vision comes in four editions, each limited to only five pieces: two editions with 18K red gold frame, combined with a NAC-coated black or a PVD-coated blue engine; and two editions with 18K white gold frame, featuring a PVD-coated purple or a red gold plated engine.
Clarity of Vision
Corundum, commonly known in its gem-quality form as sapphire crystal, is one of the hardest minerals known to man. This exceptional hardness means that sapphire watch crystals are virtually scratch-proof.
Concurrently, this also means that sapphire is extremely challenging to machine in complex three-dimensional shapes, a challenge that is compounded by the small machining tolerances required in watchmaking. Since its very first creations, MB&F has worked with ever-increasingly complicated sapphire crystal components; HM2 ‘Sapphire Vision’, the double-arched crystals of HM4 ‘Thunderbolt’, the recent HM3 FrogX and the hallucinatory body of HM6 ‘Alien Nation’ are prime examples.
More about the HM9 Engine
Its double-balance system with differential is descended from the similar mechanism in Legacy Machine N°2, albeit in vastly different aesthetic form. HM9 is exultant in its celebration of expressive design.
Horological Machine N°9 deliberately avoids inducing the resonance effect. Its purpose in including two balance wheels is to obtain discrete sets of chronometric data that can be translated by a differential to produce one stable averaged reading. This purpose would be defeated by two balances oscillating perfectly in phase, giving the same chronometric data at every point.
Regulating the twin balances is a challenge in its own category. Because the HM9 engine has two balance assemblies operating simultaneously, creating two sets of sounds, this method is not possible here. When first launched in 2018, each example of Horological Machine N°9 had to be regulated by first blocking one balance to regulate the remaining one, and vice versa. When both balances were allowed to run, the calibration would shift slightly, requiring multiple rounds of re-blocking and re-regulating before an optimal chronometric result was achieved.
Since then, the MB&F team has advanced significantly in chronometric regulation techniques, largely thanks to the experience gained in creating Legacy Machine Thunderdome. HM9-SV thus benefits from a few additional years of specialised expertise in this area — not much in calendar terms, but immeasurable in terms of savoir-faire.
