We settled on a case size of 39mm to get that sweet spot in proportions between diameter and thickness. Given that we knew we wanted to add and anti-magnetic ‘Faraday’ cage, we couldnt go any smaller than 39mm or it would look too tall.
To further break up the height of the side profile, I added some horizontal lines. This is the equivalent of the fashion trick of wearing vertical lines to make you look taller. Not that is is very thick at 12.4mm.
So what is a Faraday cage and how does it work?
A Faraday cage is a structure that is designed to block electromagnetic fields. It is named after scientist Michael Faraday, who first discovered the concept in 1836. A Faraday cage works by creating an enclosure of conductive material, such as metal mesh or metal plates, that surrounds the area to be protected. The electrical charges on the conductive material redistribute themselves in such a way as to cancel out any external electromagnetic field inside the enclosure. In this way, the cage acts as a shield, preventing the external field from entering the protected space. Faraday cages are used in a variety of applications, including protecting electronic equipment from electromagnetic interference and shielding sensitive laboratory equipment from external electromagnetic fields.
In the below diagram, you can see the extra pieces of soft iron that we added to surround the movement, protecting it from magnetic interference.
Another component of the case that we have upgraded to improve longevity is the case back gasket.
Gaskets are susceptible to wear from continuous sweat while on your wrist, as well as other chemicals like sunscreen or deodorant. Over years of use this can become a failure point. Viton rubber is formulated to be extremely resistant to chemicals and salt water. The Aoraki will have a Viton gasket on the case back to ensure long term reliability of the watch.
Another feature of the watch that we hadn’t mentioned before is drilled lugs. Drilled lugs make it easier to remove spring bars when switching between straps, although you will still need a tool to push the bar through the hole. You won’t need a tool for the changing between the stock straps that come with the watch however, as these will be single piece straps.
On that note, I noticed on the prototypes that the sharp edge on the underside of the case between the lugs was catching on the leather strap. For the production version we will machine a slice out of the case there so that the strap can slide more smoothly between the case and the spring bars.
One last detail I should mention about the prototypes. The rehaut ring will have the words ASSEMBLED IN NEW ZEALAND. The prototypes are engraved and painted, but for the production version will only be engraved.
Thanks for reading. Stay tuned for the next post in the series.