After I went hands-on with the HM6’s caliber as part of our Movement Hands-On Series in 2014, I thought it would be the last time for me to see this unique array of 475 components and 68 jewels. Happily, I was proven wrong the moment the MB&F HM6 SV “Sapphire Vision” watch debuted last year, slipping this “engine” – as MB&F likes to call it – into a sapphire crystal sandwich.
First, as we like to do, a bit of history for you. MB&F likes to praise itself as one of the starters of the sapphire craze, thanks to their mind-bendingly awesome Horological Machine 2 SV that they first launched in 2010. While the HM2 wasn’t a full sapphire watch per se (as you can see above, it still had a metal back plate), its complex single-piece sapphire front with its drilled holes certainly helped push the limits of the sapphire crystal supplier who made it.
Just to recap, sapphire crystal is very hard and, in fact, remarkably stable when you leave it alone (meaning you’re not putting a spinning diamond-tipped drill through it hundreds of times), but is very prone to cracking when it is being machined. It is no wonder, then, that it took a few years for the first fully sapphire-encased watches to appear (the Cecil Purnell Mirage and Richard Mille RM 056 debuted in 2012).
Now, the MB&F HM6 SV “Sapphire Vision” takes the HM2’s complexity to the next level by taking two massive slabs of bulbous-looking (for lack of a better word) sapphire and fits them over the incredible HM6 tourbillon movement. The top and bottom sapphire elements are fixed to a 950 platinum or 5N+ red gold band which features cool-looking lines inspired by the “Art Deco style Greyhound Streamliner buses of the 1950s and ’60s.”
The sapphire crystals feature a total of nine domes, four on the bottom and five on the top – the features they reveal, we’ll discuss soon below. Each piece has been machined from a solid block of sapphire crystal, the second hardest, naturally occurring mineral on Earth after diamonds. Hence, it comes as no surprise that diamond-tipped tools are required to eat away all the material we don’t need in order to leave behind this weird shape that must take dozens if not hundreds of hours to machine.