This November, three new Grand Seiko Hi-Beat 36000 GMT models were launched; the key highlight being the SBGJ021 that is limited to 500 pieces together with two regular production models, the SBGJ017 and SBGJ019.
The second time zone on the Grand Seiko Hi-Beat 36000 GMT is indicated by an extra hour hand that shows home time.The colours of the dial and rotor of the limited edition SBGJ021 are inspired by Mount Iwate, the mountain that can be seen from the Shizuku-ishi Watch Studio located in Morioka where all mechanical Grand Seiko wristwatches are produced.
The sapphire crystal case back allows one to view the rotor made of titanium and tungsten. The titanium portion of the rotor has shades of blue, purple, orange and yellow, similar to the colours seen at dawn on Mount Iwate.The deep red dial for example, evokes scenes of dawn as the early morning sunlight slowly brightens up Mount Iwate.
The varying thickness of the oxide film results in different colours. The titanium oxide film generates colours according to the light refraction index.Such shades are possible due to an anodic oxidation process, a surface treatment where the metal undergoes electrolysis that artificially generates an oxide film.
The use of titanium for the oscillating weight is not simply for aesthetical reasons; titanium is a material of strength and hardness. These two characteristics make it less prone to distortions arising from severe shocks. Titanium for instance, is able to absorb shock ten times better than brass and it is also corrosion-resistant.
The Grand Seiko Hi-Beat 36000 GMT watches are equipped with the Calibre 9S86 automatic movement with a balance that oscillates at 10 beats per second or 36,000 vibrations per hour. The Calibre 9S86 has the accuracy of plus 5, minus 3 seconds a day in a static position.
With such a high frequency 10-beat movement, why isn’t silicon used to mitigate the effects of friction resulting in wear-and-tear? “At this moment, we are still unsure of the durability and how good the silicium material will be,” says master watchmaker Satoshi Hiraga from Seiko Instruments Inc. “We believe MEMS is the best for making watch components and parts,” he adds.
MEMS is the acronym for Micro Electro Mechanical System, an advanced processing technology used in the manufacture of precision components such as semiconductors.
Seiko’s movements are manufactured in-house and this includes their proprietary spring alloy termed Spron used for their mainsprings and balance springs. Movement components that have to be very precise such as the escape wheel and pallets are produced with MEMS technology.
Unlike traditional production methods for component manufacture comprising pressing, cutting and polishing, MEMS involves the use of moulds made with photolithography which are layered with material to obtain the required shapes, even complex ones.
The resultant components are more precisely made as compared to cutting with surfaces that are smooth in finish. Even hard materials can be used for making components and their shapes can be adjusted to be more lightweight. When precision components are used, durability is greatly enhanced.
In the Calibre 9S68, the shock-resistant and anti-magnetic Spron 610 is used for the balance spring. Derived from the words “Spring” and “Micron”, Spron is a durable metal alloy with a high elasticity that is also corrosion-resistant and heat-resistant.
“The most difficult and challenging aspect when assembling high beat movements lie in the adjustments made to the hairspring of the balance,” says Hiraga. “This is because of the hard material [Spron 610]. While it is also challenging to adjust the 6 beat and 8 beat movements, these are easier as compared to the 10 beat calibre as the material is softer.”
Such adjustments relate to processes that also include what is known as truing the balance spring. This will enable the balance spring to run true in the centre.
Hiraga is Silver Meister (Master), Makuhari Watchmakers Workshop, Takumi Planning Department at the Watch Movement Division. He is also the master watchmaker credited for making and assembling the Calibre 6830 manual-winding movement used in the Credor Fugaku Tourbillon, Seiko’s first commercial tourbillon launched at Baselworld 2016.
We say “first commercial tourbillon” because from what we understand, Seiko had made a tourbillon a long time ago but it was not commercially launched.
“The technical challenges faced with the Credor Fugaku Tourbillon were in the assembly and adjustment of the movement. It was extremely difficult to do it and we had to create special tools to overcome the problems,” says Hiraga.