Results for Silicon Hairspring

Yacht rock: the new IWC Portugieser Yacht Club Moon & Tide boasts the brand’s first silicon hairspring

Unveiled at Watches & Wonders Shanghai 2024, its innovative tide indicator and moonphase can show high, low, spring and neap tides.The post Yacht rock: the new IWC Portugieser Yacht Club Moon & Tide boasts the brand’s first silicon hairspring appeared first on Time+Tide Watches.

First Look – The Updated IWC Portugieser Yacht Club Moon & Tide, the First IWC with a Silicon Hairspring

This year, IWC brings the emblematic Portugieser collection under the spotlight, introducing several stunning new additions to the collection, including the impressive Eternal Calendar and updates to several iconic models, such as the chronograph and the 7-day Automatic. On the occasion of Watches and Wonders Shanghai, the brand unveils a new version of its Portugieser […]

Hands On: Tudor Black Bay 41 Ref. 7941A1A0NU

Among Tudor’s new releases for 2024, the most conservative is undoubtedly the Black Bay 41 METAS ref. 7941A1A0NU, which offers a monochrome, black-and-white alternative to the gilt-and-burgundy ref. M7941A1A0RU-0003 introduced last year. Initial thoughts The new Black Bay 41 (BB41) feels instantly familiar. In fact, it’s a little surprising that it wasn’t already in the collection, being about at straightforward as a contemporary dive watch can be. But what it lacks in surprise, it makes up for in simple, tangible quality. While the BB41 was the original Black Bay – launched a dozen years ago now – it now sits atop a range that also includes the smaller Black Bay 58 and even more compact Black Bay 54. The BB41 METAS’ dimensions of 41 mm by 13.6 mm thick mean it wears similar to a modern Rolex Submariner; those looking for vintage proportions should consider the BB58 and BB54. Of course, the big news is METAS certification for the MT5602-U movement, which now carries a “U” suffix to identify it as a METAS-certified Master Chronometer. The differences from the standard MT5602 used to date are likely minimal, since the movement has always had a silicon hairspring, one of the most important features for resisting the METAS standard’s 15,000 gauss anti-magnetism test. The difference, therefore, is that the movement’s high-performance specs have been confirmed by an independent test. Tudor is all about value, and the BB41 METAS is no exception. Available with...

Ulysse Nardin Introduces the Military-Inspired Diver OPS

Ulysse Nardin just dropped the Diver Net OPS and Diver X Skeleton OPS, a pair of military-inspired sports watches made from sustainable materials. Dressed in olive drab and black, the two watches utilise recycled steel and carbon composites, and even nylon straps made from fishing nets. Though the emphasis on sustainability and styling are clearly modern, the basis of the watches is historical: the design is modelled on the shipborne marine chronometers Ulysse Nardin was once famous for. The Diver X Skeleton OPS with its open dial Initial Thoughts Ulysse Nardin opted for more restrained aesthetics for the new Diver Duo, instead of the brighter colours found on past models. The Diver Net OPS in particular has a low-key, functional look. Notably, the trademark “X” motif on its dial – which you either love or hate – is not particularly obvious. I find the “X” too bold on some other designs, but here it works better with the military-esque look of the dial. However, both the materials and movements found inside the two watches reflect the brand’s focus on advanced, industrial watchmaking. The Diver Net OPS, for example, is an entry-level model but still equipped with an in-house movement with a silicon hairspring and free-sprung balance, along with a diamond-coated escapement. The Diver Net OPS And the use of recycled materials is also interesting. The carbon composite parts of the case are offcuts from the aircraft manufacturing, which according to the brand red...

Longines’ New Legend Diver in the Old Size

Recognised by its distinctive dual crowns and an internal rotating bezel, the Longines Legend Diver pays homage to history while embracing modern enhancements. Already a mainstay of Longines’ reissue sports watches, the Legend Diver has undergone a transformation and now features a redesigned and smaller 39 mm case that faithfully echoes the original (while it predecessor was 41 mm). Initial thoughts The new Legend Diver carefully retains the vintage styling of its predecessor. Traditionalists will appreciate the absence of the date that was found on the prior version. The absent dial preserves the dial’s clean and uncluttered aesthetic. But the new Legend Diver is not just a remake. Inside is the cal. 888.6, an upgraded ETA calibre that stands out with a 72-hour power reserve and magnetic resistance that exceeds the ISO 764 standard by ten times thanks to a silicon hairspring. And the dial similarly retains the design of the vintage original, but is executed in a modern manner with two colours of Super-Luminova, green and blue. This not only adds a touch of excellence to the design but also enhances readability in low-light conditions. On its face, the downsizing to 39 mm may not align with the conventions of a tool watch, especially one conceived for diving. However, this shift in size caters better to daily wear and better reproduces the original’s dimensions. Unfortunately, the reduction in diameter doesn’t go hand in hand with a decrease in thickness, so the ...

The Longines Master Collection Small Seconds is what happens when a brand listens to enthusiasts

Longines unveils an engraved trio with three different dial colours in three different finishes The watches are downsized from 40mm to 38.5mm, in a move destined to be popular among enthusiasts An azurage-finish petite seconde is courtesy of the silicon hairspring-equipped L893.5 How often do you see a brand new release that immediately captures you? … ContinuedThe post The Longines Master Collection Small Seconds is what happens when a brand listens to enthusiasts appeared first on Time+Tide Watches.

In Conversation with Gregory Kissling About Omega’s New Spirate System

At the launch of the new Speedmaster Super Racing at Omega’s HQ in Bienne, Wei speaks with VP of Product, Gregory Kissling, to learn in detail about the brand’s latest groundbreaking invention, the Spirate System. Kissling gives a masterclass on the unique geometry of the Spirate’s silicon hairspring that has been formed through Deep Reactive […]

Omega Introduces the Spirate Hairspring in the Speedmaster Super Racing

Having teased about a new innovation on social media for several weeks, specifically a “tiny device” that would be a game-changer for the Speedmaster, Omega has finally revealed the Speedmaster Super Racing. But the star of the show is not the watch but actually the technology in the all-new silicon hairspring within the latest Speedmaster. Known as Spirate, a portmanteau of “silicon” and “rate”, the new hairspring has a proprietary form that allows a watchmaker to vary the tension along its length, theoretically enabling fine adjustment of up to a tenth of a second. The result is a watch certified to have a daily rate of 0/+2 seconds, the most stringent timekeeping criteria amongst Omega watches.  Initial thoughts  While it is a given that Omega debuts a new Speedmaster every year, several of them at a go in fact, the revolutionary innovation in the hairspring was unexpected (though anyone who was trawling the Swiss patent registry would have gotten some hints). The patented Spirate hairspring The technical innovation behind Spirate is unquestionable, though the benefit to the wearer is probably less than the advantage it brings Omega in terms of streamlining regulation during production and assembly. And when Omega starts equipping its offerings with Spirate on a large scale, it will be an achievement from the perspective of industrial production.   As for the Speedmaster Super Racing itself, well, the watch is less than spectacular. Visually it’s sim...

Tudor Introduces the Black Bay Pro

Tudor finally introduces a more compact GMT watch with the Black Bay Pro, which is 39 mm and equipped with a fixed bezel. With slightly retro styling, the Black Bay Pro nonetheless has all the features that characterise Tudor, including a proprietary movement with a silicon hairspring as well as the newly-developed T-Fit micro-adjustment clasp. Initial thoughts The Black Bay Pro is what I have been hoping for, a more compact Tudor GMT. It has a 39 mm case just like the Black Bay Fifty-Eight, the perfect size in my estimation. And it has a true GMT function thanks to the MT5652 inside. It also sports a useful upgrade: the T-Fit clasp that allows for micro-adjustment on the fly, giving this a feature usually found on pricier watches. The aesthetic certainly beings to mind the Rolex Explorer II ref. 1655, which is a good thing (and it was probably designed with a knowing wink). Arguably the only downside is the case thickness. At 14.6 mm high the watch is thick, though not excessively so. It does not feel ungainly on the wrist, although the flat, vertical case sides do accentuate the height. Another only potential downside is the fixed bezel, which means the watch cannot track the third time zone that’s possible on the standard GMT. It’s not a dealbreaker for me since the third time zone functionality is something I never use on a GMT watch. Still, the Black Bay Pro is an impressive value proposition all things considered, and certainly one of the best buys of the fair. F...

Breguet Unveils the Classique Tourbillon Extra Plat Anniversaire 5365

Breguet is marking its invention of the tourbillon – way back in 1801, or 220 years ago – with an elegantly simple variant of its extra-thin tourbillon. The Classique Tourbillon Extra Plat Anniversaire 5365 is classically Breguet in style, with a handful of aesthetic flourishes to mark it out as an anniversary edition. And it is truly a limited edition of only 35 watches, which is also the number of tourbillon pocket watches Abraham-Louis Breguet made in his lifetime. Initial thoughts Breguet’s Tourbillon Extra Plat is already impressively executed for a slim, simple watch, especially with a skeleton movement. The cal. 581 inside is typical of modern-day Breguet movements – incorporating technology in the form of a silicon hairspring and escapement, while boasting a high level of hand finishing. Fortunately, the anniversary edition doesn’t try to do too much differently. In fact, it is almost indistinguishable from the standard version. But that simplicity is appealing because it captures the spirit of Breguet, especially in its details like the off-centre dial and spherical, gold minute markers. Perhaps the only downside of the watch is its thinness. The case is so slim that its relatively wide diameter gives it disc-like proportions on the wrist, especially with its narrow, long lugs. A subtle tribute Just two small details on the dial mark it out as the anniversary edition. One is engraved just above the tourbillon aperture, the number of the patent awarded to...

Ulysse Nardin Debuts the Marine Torpilleur 175 Years Collection

Historically a major producer of marine chronometers, Ulysse Nardin has repurposed the concept in the modern day for its bestselling line of wristwatches that retain the face of a marine chronometer while having in-house movements and eminently reasonable prices. For its 175th anniversary, Ulysse Nardin has unveiled the Marine Torpilleur 175 Years collection, a suite of limited-edition watches starting with an affordable base model and ending with a range-topping tourbillon featuring a fired-enamel dial. Initial thoughts Originally introduced as an entry-level Marine model – it was named after a torpedo boat – the Marine Torpilleur has been successful enough that it’s now an entire anniversary line up. The expansion of the line is a good thing, because the Torpilleur is classically handsome and generally good value. All the Torpilleur models are largish at 42 mm in diameter, but most are slim, with heights of about 11 mm, though the chronograph is understandably wider and thicker. As a result, they appear relatively thin on the wrist, especially for a sporty watch. The tourbillon with a black enamel dial, and next to it a vintage Ulysse Nardin chronometer pocket watch with tourbillon regulator And the watches are all equipped with high-spec in-house movements, which is a big factor in their value propositions. Even the base model, which costs US$8,200 in its simplest version, is equipped with the UN-118, a movement that has a silicon hairspring and escapement, along...

Longines Remakes the 1950s Silver Arrow

Named after the aluminium-bodied Mercedes-Benz Formula 1 cars of the 1950s, the Longines Silver Arrow was introduced in 1956. Typical of mid-20th century gentlemen’s watches, the Silver Arrow is a functional but elegant design with a discreet flourish in the form of fluted hour markers. Notably, the Silver Arrow was first reproduced about a decade ago, but with a date and simpler execution all around. Now it returns as a more sophisticated remake that is far closer to the vintage original, but with a latest generation ETA movement equipped with a silicon hairspring. Initial thoughts Like the brand’s other recent remakes, the Silver Arrow maintains the look and feel of the original, albeit enlarged as most reproductions are. The dial has the details of the original, as does the thin case and even the crown. Longines’ Heritage remakes are often modelled on military-issue or sports watches, resulting in a strongly utilitarian aesthetic. The Silver Arrow is different, offering another look while still preserving the strong value of Longines’ historical remakes. Priced at US$2,100, the Silver Arrow will be difficult to beat in terms of classical watches in its price segment. Silver Arrow redux The silver dial features unusual, fluted indices just like the vintage original. That, along with the sword hands and correct typography create a faithful replica of the 1956 Silver Arrow. As is standard practice, the remake is larger than the original, although the new Silver Arr...

Tudor Introduces the Pelagos “Qatar Watch Club”

Founded two years ago, the Qatar Watch Club (QWC) is a community of internet-savvy watch enthusiasts in the wealthy Arab nation. The club recently got together with Tudor and local watch retailer Fifty One East to create the Pelagos “Qatar Watch Club”, a limited edition of the brand’s top-spec dive watch. The second QWC edition after last year’s Chopard L.U.C GMT, the Pelagos has “Qatar” in Arabic, or “قطر‎”, on the dial at six, replacing the five lines of text on the standard model, giving it a much cleaner look. The other point of distinction is the club logo engraved on the case back. The rest of the watch is identical to the standard model, which means a titanium case rated to 500 m and a scratch-resistant, blue-ceramic bezel insert. And the watch is equipped with the MT5612 movement. A proprietary calibre produced by Kenissi, a joint venture Tudor shares with Chanel, the calibre has a 70-hour power reserve, silicon hairspring, and is an all-round strong performer, particularly at this price point. The watch is delivered in a box bearing the QWC logo, as well as an additional blue rubber strap. Only 50 were produced – the club has 50 members – and at press time all have been spoken for. QWC members at last year’s launch event for the Chopard L.U.C GMT QWC edition. Photo – QWC Key facts Tudor Pelagos Qatar Watch Club Special Edition Ref. M25600TB-0001 Diameter: 42 mm Thickness: 14.3 mm Material: Titanium Water resistance: 500 m Movement:...

The Value Proposition: The Longines Heritage Classic 'Sector'

A truly classic 1930s design is revived as an affordable automatic with silicon hairspring.

Omega Unveils Seamaster Planet Ocean Tokyo 2020 Limited Edition

As Tokyo counts down to hosting the 2020 Olympics, the games’ official timekeeper is also counting down with progressive rollouts of limited edition watches. Exactly a year to the start of Tokyo 2020, Omega has announced a pair of commemorative dive watches: the Seamaster Aqua Terra Tokyo 2020 and the slightly less interesting Seamaster Planet Ocean Tokyo 2020. Inspired by the Japanese flag, the Seamaster Planet Ocean Tokyo 2020 Limited Edition is clad in white with red accents. It is based on the midsize Planet Ocean, so the steel case is 39.5mm in diameter (the largest size is 43.5mm). Both the dial and bezel insert in white ceramic. The “lollipop” tip of the seconds hand is in red, as is the “20” on the bezel. Inside is the Master Chronometer cal. 8800, a top of the line automatic movement with various innovations designed to ensure good timekeeping over long periods, including a silicon hairspring and Co-Axial escapement. And special alloys used for the escapement ensure it is magnetism-resistant to 15,000 Gauss.   Key facts Diameter: 39.5mm Material: Stainless steel Movement: Master Chronometer Calibre 8800 Functions: Hours, minutes, seconds, and date Winding: Automatic Frequency: 25,200bph, or 3.5Hz Power reserve: 55 hours Strap: Delivered with three options – steel bracelet, rubber strap lined with white crocodile leather, and fabric “NATO” strap. Price and availability The Seamaster Planet Ocean Tokyo 2020 Limited Edition (ref. 522.33.4...

Tudor Introduces the Black Bay Ceramic One “Only Watch”

Continuing the tradition of one of a kind dive watches for Only Watch that started in 2015, Tudor has just unveiled the Black Bay Ceramic One. Entirely clad in matte black but composed of several different materials, the Black Bay Ceramic One is starkly different from any other Tudor dive watch. The 41mm case is made of ceramic, while the bezel is black-coated titanium fitted with a ceramic bezel insert. Both the case back and crown and black-coated steel, but the back is unusual – it’s the only Tudor watch with a display back aside from the little loved North Flag. The sapphire back reveals the MT5602 movement, a “manufacture” calibre with 70-hour power reserve and silicon hairspring. The dial is all-black to match, with the markings and text printed in glossy back to distinguish them from the matte black dial surface. The hands and hour markers are filled with black Super-Luminova, which will glow green in the dark, albeit dimly. And the strap is rubber, but lined on the top with matte black alligator, which is the same construction as the rubber-calf strap found on the recently launched Black Bay P01. The Black Bay Ceramic One (ref. M7921/001CN) has an estimate of 4,500-5,500 Swiss francs. If past Tudor watches made for Only Watch are anything to go by, it will blow right past the estimate straight out of the gate and probably finish just over 300,000 Swiss francs. It’ll be sold on November 9, 2019 at Christie’s in Geneva. Visit onlywatch.com for the ...

In-Depth: TAG Heuer Achieves Carbon Hairspring Industrialisation

TAG Heuer is marking the rollout of its new-and-improved, and in-house, carbon hairsprings – timed to coincide with the 350th anniversary of the hairspring’s invention – with a pair of chronographs: the Monaco Flyback Chronograph TH-Carbonspring and Carrera Chronograph Tourbillon Extreme Sport TH-Carbonspring. More than just two new watches, the TH-Carbonspring is a notable technical achievement that might promise an entirely new generation of TAG Heuer movements equipped with oscillators that boast all of the advantages of silicon, but with added robustness. Protected by several patents, TH-Carbonspring is also the result of a fascinating process of research and development to overcome a surprising problem. Kitted out in carbon composite dials and cases, the two watches are centred on TAG Heuer’s latest-generation carbon-nanocomposite balance springs, with each being a limited edition of just 50 pieces Initial thoughts Both models serve as a launch platform for TAG Heuer’s improved and industrialisation-ready carbon hairspring. While the brand has been flirting with carbon hairsprings since 2019, its use of the technology has been intermittent and on limited scale. TAG Heuer explains previous attempts at carbon springs were not up to the brand’s standards, which is to say the hairsprings did not perform as expected and could not be produced at scale. The new TH-Carbonspring indicates TAG Heuer has perfected the technology to make reliable hairsprings, which m...

Insight: Hairspring Materials and Evolution Part II

Part I of our story on the evolution of hairspring materials covered temperature compensation along with the development of the first specialised balance spring alloy, Elinvar. The story brought us to the 1920s, when scientist and horologist Charles-Edouard Guillaume (1861-1938) finished his work on nickel-iron alloys and watchmakers begun embracing Elinvar springs paired with mono-metallic balances. In this second part we turn to newer hairspring alloys, like the now-ubiquitous Nivarox. Then we look at today’s landscape and the future, touching on research done by the Swatch Group with alternative, niobium-based alloys and also the specialised but obscure Seiko SPRON 610 hairspring. Lastly we discuss silicon springs, which are growing more prevalent across a range of timepieces. Elinvar’s weaknesses Elinvar was by far the greatest breakthrough in self-compensating alloy hairsprings at the time. Guillaume considered Elinvar good enough and not needing further improvement - unsurprisingly since he was its inventor - but other watchmakers and engineers continued to experiment with iron-nickel compounds because Elinvar’s inherent properties made it a good, but imperfect, material. Even though the alloy behaved predictably with temperature changes, its physical properties were not ideal to begin with. Elinvar was a soft metal, which posed its own suite of problems for spring applications. The importance of softness in terms of hairspring performance is not related ...

Revolution Awards 2025: Material Innovation - TAG Heuer Carbon Hairspring

Frederique Constant Unveils 40 Hz Silicon Oscillator

Best known for affordable complications, Frederique Constant’s recent watches include a flyback chronograph for US$4,000 and a perpetual calendar for a bit under US$10,000. But the brand has also applied modern technology to its watchmaking with its analog smartwatches. The brand’s latest offering is cutting-edge horology, but in a mechanical movement. The Slimline Monolithic Manufacture is equipped with an automatic movement that runs at 40 Hz, or 288,000 beats per hour (bph), thanks to a compliant-mechanism silicon oscillator instead of a balance wheel. Initial thoughts It’s a pleasant surprise to see Frederique Constant delving into advanced horological solutions with its silicon compliant mechanism and entering a space often associated with pricier brands like Ulysse Nardin and Zenith. Even more impressive is the fact that the movement is not just as a concept, but a commercially available watch that will be in stores in fall of this year and priced relatively affordably, starting at €4,495, or about US$5,300, in steel. The advanced movement leaves the design of the Monolithic Manufacture incongruous with its classical styling and a truly modern oscillator. However, as such watches go, the design is not the point – it is all about the novel escapement that will certainly pique the interest of technical-minded enthusiasts. Hi-tech collab The high-frequency silicon oscillator was born of a collaboration with Flexous, a startup focused on compliant mechanis...

Explained: The Rolex Parachrom Hairspring

Over the last decade, metal alloy hairsprings seem to fallen out of favour across watchmaking, with even conservative, haute horlogerie brands like Breguet and Patek Philippe turning to silicon balance springs. Not to mention large-scale makers of sporty watches like Omega and Tudor, which already transitioned to silicon balance springs. Rolex, however, stands out. The Geneva marque continues to employ a hairspring fabricated of its proprietary blue alloy – the Parachrom hairspring. The Parachrom hairspring inside the cal. 4131 of the Cosmograph Daytona The advantages of alloy The use of blue Parachrom is rooted in the simple fact that the right metal alloy boasts performance that is at least on par with its silicon counterpart – while offering some distinct advantages missing in silicon. Alloy hairsprings are traditionally made of Nivarox (and its family of related alloys), a special alloy that neither oxidises nor change its dimensions with variations in temperature. Invented in 1933 and almost a century old, Nivarox is a mix of nickel and iron, making it a ferromagnetic alloy, thus susceptible to influence from magnetic fields.  The cal. 3255 of the Day-Date 40 is equipped with a Parachrom hairspring. Image – Rolex In order to make its hairsprings more resistant to magnetism and to bypass the Swatch-imposed monopoly on Nivarox hairsprings (Nivarox-FAR being one of the key companies of Swatch Group), Rolex set out to develop its own hairspring alloy in the early 2...

Down to the Wire: De Bethune’s In-House Hairsprings

De Bethune plans to bring hairspring production in house, aiming to become one of the very few firms able to process alloy wire into a finished balance hairspring. This requires De Bethune’s new hairspring workshop to master wire drawing, rolling, cutting, heat treatment, and assembly. The rationale? “Externally produced hairsprings meet standards based on averages that do not enable fine adjustment of the dimensions to suit a particular balance wheel or its specific positioning in a calibre,” according to De Bethune. De Bethune’s “flat end curve” mated to a hairspring sourced from a supplier. Initial thoughts As De Bethune explains it, making its own hairsprings will allow the brand to tailor its hairspring to a specific balance or movement. Since its founding in 2002, De Bethune has presented itself as being on the cutting edge of chronometry, debuting a new balance design every year from 2004 to 2010. The brand was also quick to embrace silicon, and even briefly attempted a kilohertz magnetic oscillator system, Résonique. A new year, a new balance. Sometimes two new balances. Given De Bethune’s focus on chronometry, making its own hairsprings seems like a natural next step. However, there is a reason so few brands make their own hairsprings: the process is a difficult and demanding one that benefits greatly from economies of scale. For example, H. Moser & Cie. makes less than 4,000 watches per year, however, its sister company Precision Engineering claims...

In-Depth: Orient Star’s Smart Silicon Escape Wheel

While silicon mechanical movement components have swept across Switzerland, adoption has been slow within the Japanese watch industry, stymied by Swiss patents and professed concerns over the material’s durability. To this day, it remains the unlikely domain of Orient Star, a small brand with priority access to Seiko Epson’s massive industrial base. This positions Orient Star to capitalise on consumer demand for increasingly long power reserves, without sacrificing performance. Thanks to an ultralight and geometrically efficient escape wheel with a patented design, Orient Star is able to deliver a 70-hour power reserve without resorting the same counter-productive trade-offs to balance energy made by some Swiss peers – here’s how it was done. A silicon wafer of escape wheels. Image – Seiko Epson The quest for longer power reserves Recent consumer demand for longer power reserves has sent the industry’s engineers scrambling for ways to increase the autonomy of existing movement platforms. A movement’s power reserve is dictated by the length of the mainspring, which unwinds at a constant rate. That is why using a chronograph doesn’t cause a watch to run down faster – usually. Of course, you need to find somewhere to fit that extra length of mainspring while maintaining the movement’s dimensions, such as by thinning out the barrel walls, narrowing the inner barrel arbour radius, or, reducing the thickness of the mainspring. However, while decreasing the ma...

Insight: Hairspring Materials and Evolution Part I

The invention of the hairspring was among the greatest breakthroughs in horology, since its inception suddenly made mechanical timepieces portable, transforming clocks into watches. This not only marked the start of precision timekeeping, but also set mankind upon the long road to perfecting the accuracy of mechanical watches, arguably the most sophisticated pieces of kit on Earth at the time, when such precision was paramount for fields as varied as navigation, warfare, and astronomy. The hairspring turned 350 years old in 2025 and we’re marking the occasion with a series of stories on the topic, including the story of the spiral hairspring and also the importance and evolution of the overcoil. Now we turn to temperature compensation and metallurgy in a two-part story covering the evolution of the hairspring materials up until metal alloys. More exotic materials and inventions will follow in Part II. Elasticity and thermal expandability  One of the fundamental factors in hairspring function is ambient temperature, simply because metal alloys expand or contract uni-directionally with a change in temperature. As a result, watchmakers used calorimetry, the science of temperature effects, and material science, specifically metal alloys, to their gain in advancing hairspring technology. The equation below shows the relation between the initial length of a metal strip L0, measured at a given temperature and the final length LT after a certain change in temperature.  The equ...

Insight: The Overcoil Hairspring, From Breguet to Phillips

While the invention of the spiral hairspring by Christiaan Huygens in 1675 kickstarted a revolution in terms of portable precision timekeeping, the concept was far from fully developed. It was arguably only with the later invention of the overcoil hairspring that the ideal oscillator in portable watches emerged. For many years horologists - theoreticians and artisans alike - worked to perfect the balance-hairspring assembly to optimise its performance, notably in terms of isochronism. True isochronism became a sort of holy grail for watchmakers all around the world, who all sought to ameliorate the inherent quirks of the sprung oscillator. The recent Breguet Soucription features an overcoil hairspring of non-magnetic Nivachron alloy The need for end curves The quest for isochronism was a true challenge for horologists. Isochronism is the ability of the balance-hairspring assembly the have the same period of oscillation for small and large amplitudes alike. In other words, the balance oscillation takes the same period of time regardless of the degree travelled. This is very important, since a balance usually swings with high amplitude with a fully wound mainspring and then runs at progressively smaller amplitude as the barrel unwinds. As a timepiece is required to keep good time regardless of  its winding state, an oscillator whose period is independent from its amplitude is needed. (Another solution to this is to optimise the energy delivery from the mainspring with a...