Home Featured Article In-Depth: The Grand Seiko T0 Constant Force Concept Tourbillon, The First Tourbillon Movement From Grand Seiko

In-Depth: The Grand Seiko T0 Constant Force Concept Tourbillon, The First Tourbillon Movement From Grand Seiko

by Jack Forster
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As Grand Seiko has continued to evolve over the previous couple of years (the watches solely turned out there exterior Japan, in varied worldwide markets, in 2010, and Grand Seiko was break up off from Seiko as its personal model in 2018, as HODINKEE Executive Editor Joe Thompson reported), its id has modified enormously from the insider’s secret that it was within the earlier a part of the 2000s. What hasn’t modified is the dedication to high quality and craftsmanship, however the firm is now out there throughout a far wider vary of costs than ever earlier than (the concept of a near-$80,000 Grand Seiko continues to be one thing I am getting used to), and Grand Seiko has grow to be, in current months, an apparent locus for the exploration of additional refinements in technical watchmaking as nicely. 

We now have had two new calibers launched this yr – the brand new Spring Drive caliber 9RA5, and a brand new Hello-Beat caliber, with a brand new escapement, the caliber 9SA5. Each represented vital enhancements in versatility and efficiency over their fast predecessors, however the 9SA5 was, for mechanical watch fans, undoubtedly the larger information, particularly since you do not precisely hear about new escapements every day – notably ones that may be produced on an industrial scale (although, for the second, the motion exists in simply the SLGH002, through which it was launched). 

Grand Seiko has simply introduced that, in parallel with the event course of for the 9SA5, it was additionally engaged on an idea motion venture, which in line with GS helped produce knowledge which was instrumental within the evolution of the 9SA5 into its closing kind. This idea motion is fairly fascinating in its personal proper – the tourbillon caliber T0, which, along with being the primary tourbillon from Grand Seiko, can also be the primary watch of any form from GS (or some other Seiko model, for that matter) to include the fixed pressure gadget often known as the remontoire.

Caliber T0, constant-force tourbillon, with twin mainspring barrels and double tourbillon cage.

I say that that is the first-ever tourbillon from Grand Seiko, and it’s. Nevertheless, it is not the primary Seiko tourbillon – that was the Credor “Fugaku” tourbillon, which we had a chance to go hands-on with back in 2016. That, nonetheless, was a reasonably typical tourbillon at the least from a mechanical standpoint, though it actually was a dramatic piece artistically, with a really elaborate enamel dial representing a well-known print by Hokusai, The Nice Wave Off Kanagawa. I believe there are literally some aesthetic similarities between that tourbillon and the T0 (that is “tee zero” by the best way), though mechanically talking, the T0 is a much more technically superior mechanism.

Leaving apart aesthetics, nonetheless, I believe that the T0 tourbillon is a a lot nearer relative to the 9SA5. Each are calibers which, although clearly designed as an expression of uniquely Grand Seiko aesthetics, are also primarily involved with precision timekeeping, which has been, in flip, a major concern with Grand Seiko since its inception. The T0 was designed particularly to check the boundaries reachable by way of precision and accuracy, in a testbed motion implementing new manufacturing processes and applied sciences. The efficiency of the T0 over the 50-hour operating time throughout which the remontoire is engaged may be very spectacular: ±0.5 seconds most deviation in fee per day. Grand Seiko is cautious to level out that this knowledge comes from testing underneath laboratory situations, which might not essentially duplicate real-life outcomes, however to get fee stability, even underneath such circumstances, which improves on the chronometer spec by an order of magnitude, is exceptional.

Caliber 9SA5, Hello-Beat with Grand Seiko Twin Impulse Escapment.

There are only a few watches of any form fitted with a remontoire, and the variety of watches which embody each a tourbillon and a remontoire may be very small certainly. Francois-Paul Journe was the primary to suit a remontoire to a tourbillon in a wristwatch in 1991, however since then, there have been valuable few such watches launched. IWC launched the Sidérale Scafusia which, along with the remontoire on the tourbillon, additionally has a sidereal time complication. There may be additionally the little-known however most spectacular and fascinating Haldimann H2 Flying Resonance Tourbillon which, along with being a resonance tourbillon with two balances on the carriage and a flying tourbillon and a resonance tourbillon, additionally has two remontoires on every of the 2 escape wheels. We must also not overlook the Andreas Strehler Trans-Axial Tourbillon, to which HODINKEE’s Nick Manousos launched us final yr. There may be additionally an unfinished pocket watch motion by George Daniels, in the London Science Museum, which has a co-axial escapement and remontoire. The mix of a tourbillon with a remontoire is sufficiently uncommon and weird that every certainly one of these watches and their calibers – together with the T0 – current distinctive options and mechanical options.

The motivation behind the invention of the remontoire (the primary to be positioned in a watch was one designed by John Harrison for his H4 marine chronometer, though he had invented one earlier, for the H2 experimental sea clock) is that the torque supplied by a mainspring decreases because the mainspring winds down. This, in flip, tends to amplify poise and positional errors, so ideally you’d have a means of supplying an unvarying quantity of torque to the escapement and stability. The fusée and chain was invented to handle this problem, which was most extreme within the early days of horology due to the unavailability of something apart from plain metal mainsprings, and in addition owing to the sensitivity of the verge escapement (particularly pre-balance spring) to variations in energy. The fusée is a superb resolution, nevertheless it does take up appreciable area within the motion, and as nicely, it does not present essentially the most precise potential resolution to offering fixed torque. Strehler put it very nicely in his dialogue of his personal tourbillon with Nick, remarking, “Attributable to its development with an outlined fusée spiral, the chain-and-fusée solely compensates a theoretical variation of the torque of the mainspring, however not the ability variation of the true mainspring, friction variations, influences from issues, and so forth. These elements can solely be compensated by a remontoire, located instantly earlier than the escapement and performing like a filter.”

One fascinating be aware on the design: The stability wheel is modeled after a Japanese image often known as the tomoe. This image resembles the Chinese language Taiji image (informally often known as the yin-yang image) and is commonly present in household crests and in symbolic iconography at Shinto shrines. The image may be very historical and has many various ranges of which means – semiotically polyvalent, as my lit-crit associates would say.

A remontoire is actually a secondary mainspring, which is on one of many going practice wheels (the fourth wheel) or on the escape wheel. It’s periodically rewound by the mainspring, which doesn’t immediately drive the stability – as a substitute, the function of the mainspring is to maintain the remontoire spring underneath fixed rigidity. So long as there’s sufficient power within the mainspring to maintain the remontoire spring wound, there will probably be basically a relentless quantity of torque delivered to the stability. 

The internal and outer tourbillon cages (blue) and the higher tourbillon bridge. At about 12: 30 you may see the ultimate going practice wheel that drives the outer tourbillon carriage. The cease lever for the tourbillon is the blade spring seen just under. The MEMS-fabricated skeletonized escape wheel is on the higher left, 11: 00-12: 00, and the ceramic cease wheel for the remontoire is at 5: 00-6: 00.

The caliber T0 was designed by a workforce led by Takuma Kawauchiya over a five-year interval. Energy comes from two mainspring barrels which run in parallel – mainspring barrels operating in sequence present an extended energy reserve, however operating them in parallel – that’s, with each feeding power to the going practice individually, and on the similar time – supplies double the torque, and that is needed within the T0 to energy the remontoire, which provides significantly to the ability calls for of the motion general. The theoretical operating time is 72 hours, nonetheless the reserve throughout which there’s sufficient torque for the remontoire is about 50 hours (this discount is par for the course with remontoires). Hand ending is discovered all through the motion (ending the elements, says GS, took about three months), and a particular hardening approach was developed for the second and third going practice wheels to be able to scale back friction on the tooth and pinions and enhance energy stream. The 2 tourbillon cages are in blued titanium, and the stability has adjustable timing screws for fee adjustment and a flat stability spring (that is in distinction to the overcoil discovered within the 9SA5; the overcoil was omitted within the T0 to be able to scale back the already appreciable top of the motion). 

Understanding how the remontoire works generally is a little complicated at first – if you first have a look at the T0, you assume you’re looking at a three-legged higher tourbillon bridge, underneath which is a single tourbillon cage with six blued titanium arms. What you’re really taking a look at are two separate tourbillon cages, every with three arms. The outer cage, which carries the fixed pressure mechanism, is pushed by the gear practice. The fixed pressure cease wheel, which rotates one tooth per second to maintain the remontoire spring wound, and the escape wheel, are each rotating across the similar mounted wheel. 

Kawauchyiya explains, “Because the outer carriage turns, it costs the fixed pressure spring connecting the outer and internal carriage, and the charged power will drive the internal tourbillon carriage. A pallet stone ‘stopper’ hooked up to the internal carriage which meshes with the tooth of the cease wheel [which is made of ceramic] is used to manage the distribution of power from the fixed pressure spring, and as power of the constant-force spring is launched, the power is provided to the internal carriage that drives the escape wheel that meshes with the stationary wheel. The escape wheel now provides fixed and uniform power to the stability. Whereas the internal carriage is rotating, the outer carriage is stopped by the engagement of the stopper and the cease wheel. When the internal carriage rotates by six levels, the engagement of the stopper and the cease wheel is launched and the outer carriage rotates to supply power to the fixed pressure spring. When the outer carriage rotates by six levels, the following tooth of the cease wheel engages the stopper and the outer carriage stops once more. This sequence of actions takes place in one-second cycles, in order that the second hand makes deadbeat movement.”

On this video supplied by Grand Seiko, you may really see the outer carriage executing its one-second bounce.

One different fairly uncommon characteristic of the watch is that it’s, comparatively talking, a fairly high-frequency tourbillon, at 28,800 vph (the default appears to be 21,600 vph in trendy tourbillon wristwatches). Now, this isn’t by any means the best frequency tourbillon ever made – in 2012, the TAG Heuer MikrotourbillonS debuted with two tourbillons, one for the going practice and one for the chronograph, and the one for the chronograph ran at 360,000 vph, which is, you realize, fairly damned quick. Nevertheless, I believe this can be the best frequency tourbillon ever outfitted with a remontoire.

If you wish to see the T0 Tourbillon in individual, you’ll have to journey to Japan – particularly, to the Grand Seiko Studio Shizukuishi, in Morioka, which is Grand Seiko’s new manufacturing facility, inaugurated earlier this yr. As this can be a idea piece, it is not on the market (although it might not shock me if as soon as the information is out that it exists, some individual, or some a number of individuals, attempt to purchase it anyway. Nothing piques the curiosity of the high-end collector like being instructed they cannot have one thing). It doesn’t all the time occur that fascinating idea items grow to be manufacturing watches, nevertheless it does occur often – the Cartier ID One and Two idea watches stay, sadly, solely (now already half-forgotten) idea initiatives, however then again, the Piaget Altiplano Ultimate Concept watch is being sequence produced, which I actually did not count on – in minuscule numbers, however nonetheless, it is a manufacturing watch. I do not know to what extent the remontoire would have to be redesigned for a non-tourbillon watch (I believe the reply is “significantly”), however I would not thoughts within the least seeing a hand-wound Hello-Beat non-tourby with a remontoire. In any case, I strongly suspect that GS did not make this fascinating caliber simply to offer individuals who get to Morioka one thing to admire. In some kind, I believe a few of this tech goes to finish up out on the earth, in manufacturing watches. Time, as regular, will inform.

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