Image courtesy of Dr. Crott Consulting SARL.

March 2022 17 Min Read

Derek Pratt: The Forgotten Watchmaker

By A Collected Man

You’ll likely never see a watch bearing the name Derek Pratt. Although they are rarely seen at auction, there is a loan display at The Science Museum in the exhibition collated by the Worshipful Company of Clockmakers, which only speaks to the significance of his work. This relative lack of visibility betrays the skill, ingenuity, and generosity that made up Derek Pratt. The English watchmaker might be best known to collectors for his incredible work at Urban Jürgensen alongside Peter Baumberger, or perhaps for his unfinished replica of Harrison’s H4 chronometer. However, there is much more to this man than these two projects.

It’s been nearly 13 years since Pratt’s death and in that time the world of independent watchmaking has exploded. With a rapidly increasing interest in this field of horology, we thought it worth digging into one of the unsung heroes of British watchmaking whose mark on the craft was far larger than many are aware.

Pratt in his workshop in Switzerland holding his H4 in 2005, courtesy of Charles Frodsham & Co, London.

On the occasions that Pratt is brought up in horological circles, it is often forgotten that he was far more than a watchmaker. His engineering curiosity stretched far further than timepieces. From the Wankel-driven Mazdas he would drive around in, to the classic bikes that he could often be seen atop, Pratt’s love of mechanical things seemingly knew no bounds.

By all accounts, Pratt was at the very centre of complex horology through the 1980s and into the 2000s. He was always willing to lend a hand or just be a sounding board for ideas, and those we spoke to about Pratt could not say enough about the man’s selflessness when it came to giving his time and knowledge. Hopefully we are able to convey all of this and more in the following article, shedding some light on a man who we feel can’t be spoken about highly enough.

An Early Start

Pratt was perhaps always destined to go on to create incredible mechanisms on a tiny scale. Born in Petts Wood, just outside of Orpington, southeast London, he was close to Greenwich and all of the horological masterpieces held there. The earliest recollections of Pratt’s life come via his childhood friend, Derek Goldsmith. They grew up together and shared a passion for all things mechanical. Goldsmith would go on to make his millions by inventing a mixer valve that would become the foundation of the shower company Aqualisa. Both Pratt and Goldsmith attended Scouts together, and both had their parents install lathes in their garages, allowing them to work away on projects together through their teenage years.

Pratt in his younger years - leaning against a Mazda run by a Wankel engine (left), and on a Dursley Pedersen bicycle (right), courtesy of the British Horological Institute (BHI).

They would both go on to attend Beckenham Technical School, with Goldsmith being a year above Pratt. After graduating in 1953, Pratt would take up an apprenticeship at Smiths Industries, and later in 1956 he would start a course at the National College of Horology. This was designed to be a three-year course, where students would complete a full pocket watch in their final year. However, this program was scrapped halfway through Pratt’s course, causing him to leave early despite being an award-winning student up until that point. “He saw it as a betrayal,” says Timothy Treffry, a long-time friend of Pratt’s and former editor of the Horological Journal. From very early on, Pratt had a clear vision of what he wanted to do and his interests that would direct his later work were there for all to see.

According to the memorial written by Goldsmith in the BHI book Derek Pratt – Watchmaker, the two of them founded a company together in 1960 called Pratt and Goldsmith. They produced small, precise parts for other companies, meaning they got to do what they enjoyed most, while earning a bit of money at the same time.

The year that Pratt left his watchmaking course was the last for the National College of Horology, as they closed down shortly after. This meant that Pratt was able to start working for Andrew Fell, the college’s former director. These two would work on the clocks inside black boxes among other micro-engineering projects together. They would go on to work on micro-soldering projects that were being fuelled by the growing field of micro-electronics. This work would see Pratt emigrate to Switzerland, where he would settle with his first wife Franziska.

The Beginning of a Horological Journey

Alongside the work Pratt was doing with Fell, he started doing independent restoration work, which is a path trodden by many of today’s most successful independents. Pratt would restore old chronometers and clocks, starting a theme that would carry on throughout his career – a fascination for traditional and antiquarian horology.

While some watchmakers of his era started looking for new techniques, materials, and designs, Pratt would dedicate his life to mastering the old ways of doing things. A true historian of the craft, he would look to the works of Breguet, Harrison, and Tompion for his inspiration, hoping to carry on the tradition that these early horologists established some 200-300 years prior.

These influences are clear, not only from his work, but from his workshop. Pratt was starting to build up his collection of tools and machinery through the early 1970s, a famously tumultuous time for the watch industry. Through the Quartz crisis, thousands of jobs were lost, but this also meant the machines used for making traditional, mechanical timepieces were no longer needed. Many companies thought they would never need these tools again and were selling them for scrap. Pratt was able to take advantage of this and bought all the equipment he needed for a fraction of what it should have cost. “He was able to set up each lathe to do a specific job,” Treffry told us, “meaning he could save time by taking a part from one to the next, without having to reset the machine.”

Another one of these traditional techniques which Pratt was able to master, and one for which he attracted great acclaim, was guilloché. Pratt was able to get hold of both a rose and straight-line engine and could turn dials with incredible precision. According to Treffry, “he would unplug his telephone and ignore the door if anyone tried to call on him while he was doing this”. There is even a story of someone coming to visit Pratt while he was working on a dial and, after multiple failed attempts to get his attention by knocking on the door, they resorted to throwing snowballs at his window. It’s believed that Pratt was able to get the dial to a stage where he could stop before letting his friend in. But it just goes to show the level of concentration that he was able to reach when working on these machines.

Pratt constructing the guilloché on a dial, courtesy of Peter Baumberger in Derek Pratt: Watchmaker (BHI, 2012).

In the memorial that he wrote, and was later published in the BHI book, Dr. Helmut Crott noted that the machines that Pratt used were not – for want of a better word – cutting edge. Crott had found photos of Pratt working on a dial. “I showed these photos to my 82-year-old dial maker who has spent 65 years in the dial business,” he wrote. “He was very astonished about the tools Derek used. They seemed to him archaic, but he said someone who can use these kinds of tools must be very talented.” Pratt was clearly determined to make watches in a traditional way and wouldn’t be swayed by modernity. It was also noted by Crott that there was not a CNC machine in sight in his workshop. Pratt would often joke that he didn’t use CAD (Computer-Aided Design) either, but much preferred “CARD”. He would make scaled-up models of certain components out of cardboard, using rubber bands to power them, checking his theories before casting them in metal.

Mastering these old techniques and maintaining these aged machines meant that Pratt was able to sensitively work on vintage pieces. His restoration work would prove to be almost a constant throughout his life. It would also be the vehicle that brought him and Peter Baumberger together. Baumberger was one of the top antique dealers and would later become the owner of the Danish brand Urban Jürgensen und Sønner, a name that has links to some of the more complex watchmaking in the early 1800s. Thanks to this complexity often found in Urban Jürgensen pieces, Baumberger had trouble getting some of his pieces serviced – and it was this search that led him first meeting Pratt. Having built a reputation for working with traditional techniques and an ability to handle multifaceted movements, Pratt’s name was spreading across the cantons.

I showed these photos [of Pratt] to my 82-year-old dial maker who has spent 65 years in the dial business. He was very astonished about the tools Derek used. They seemed to him archaic, but he said someone who can use these kinds of tools must be very talented.

Dr. Helmut Crott

Pratt started doing more and more work for Baumberger, and the two eventually became close friends. When the latter was about to take full control of Urban Jürgensen und Sønner, there was really only one person he wanted to help him on the technical development side. But it wasn’t just Urban Jürgensen watches that Pratt would work on from Baumberger in the early days – he also completed a restoration of a Vacheron Constantin offered to King Fuad I in 1929.

The Urban Jürgensen Years

The movement of an open face tourbillon made by Derek Pratt for Urban Jürgensen, courtesy of Christie's. The movement bears the words 'Invenit et Fecit', a motto found on Breguet watches, while the modern collector may be familiar with them from F.P. Journe's dials.

There has recently been some noise surrounding Urban Jürgensen, as Finnish watchmaker Kari Voutilainen has taken charge as its new CEO and placed his talented daughter Venla in charge of after-sales service. There was a similar excitement surrounding Baumberger’s ownership of the brand, and it saw a rather prolific era of development, in large thanks to the ability of Pratt.

When talking about Pratt’s involvement with Urban Jürgensen, everyone we spoke to first mentioned his dials. His engine-turning work was extremely highly regarded in the industry, even after his death. When clearing out his workshop, a drawer full of discarded dials was found. To the untrained eye they appeared perfect, yet after some serious close inspection it was possible to see the smallest of errors that someone less of a perfectionist than Pratt would be OK with. But while his dial work was extraordinary, it was far from the extent of his contributions to the brand. He would become the technical director from 1982 to 2005.

An in-line engine Pratt used to create his extraordinary dials, courtesy of Peter Baumberger in Derek Pratt: Watchmaker (BHI, 2012).

When it comes to Pratt’s work with Urban Jürgensen, many will instantly think of his oval pocket watch. This was a project that would take Pratt more than two decades to complete, with the finishing touches needing to be completed by Kari Voutilainen. While its distinctive case shape may help it stand out aesthetically, the real highlight of this watch lies in its movement. For this watch, Pratt invented a new way to fit a remontoire to a gear train with a tourbillon. His innovation? Mounting the remontoire inside the tourbillon cage. He would also incorporate a détente escapement to this construction, a favourite of his thanks to its unique quality of not needing lubrication.

There were plenty of unique challenges that faced Pratt in the construction of this watch, yet it seems he tackled them all with the same determination that many saw throughout his career. He made every part of this watch by hand, even down to the screws. This particular watch had three cases made for it – one in silver, one in platinum and one in rose gold. The platinum and rose-gold examples were produced between 2005 and 2006 by Bruno Affolter, a master casemaker of Les Artisans Boîtiers, a sister company of Parmigiani. However, the silver case was made by Pratt on his lathe. Due to its oval shape, he would have to fit a special attachment to his lathe to complete the extremely intricate work. He did such a good job that master casemaker Jean-Pierre Hagmann would say this after getting the chance to examine the case, “The mastery and quality of manufacture is superb! The maker deserves the title of master casemaker!”

Notes on the oval case that Pratt wanted to construct, courtesy of Timothy Treffry, from Derek Pratt: Watchmaker (BHI, 2012).

He would also take on the challenge of forming the two glasses that would cover the front and back of the watch – not something that just any craftsman could do. Pratt sought the advice of supposedly the one man capable of shaping sapphire like this, who laughed at Pratt when he explained the dimensions of the project. When it was clear that he was going to get little assistance from him, Pratt decided to tackle it himself. He was eventually able to produce both, including the back glass that has two holes bored into it for winding and setting the watch.

Pratt was incredibly proud of this watch, even going on to add a sketch of it to his business card. However, as we mentioned above, he wasn’t able to finish the project. In 2004, as Pratt’s cancer was starting to take hold, Baumberger asked if he could hand the project off to Kari Voutilainen, who would add the final pieces to the movement along with applying the spectacular finishes. For a more in-depth guide to this watch, we recommend reading the breakdown that Dr. Helmut Crott gives in an article published on SJX last year, as there are many more extraordinary details about that watch that we don’t have space to go into here.

Of course, this wasn’t the only piece that Pratt would make for Urban Jürgensen and Baumberger. He would work on and develop the reference 2 and 3 wristwatches, where his perpetual calendar module would sit atop another F. Piguet ébauche. The only difference between these two was the addition of a power reserve indicator tracking around the bottom half of the moon phase display in the ref. 3.

The Urban Jürgensen reference 2 alongside the reference 3.

These two watches would go on to set the design codes for Urban Jürgensen for many years to come. Their stylised tear-drop lugs, observatory hands and fine guilloché dials would become the standard for many of the brand’s lines after Pratt and Baumberger died. Given the skill that Voutilainen (who, as we mentioned above, had worked with both Pratt and Baumberger previously) is known for in dial work, one can only presume these traditions will be continued when his first pieces for the company are revealed.

The George Daniel's Relationship

Looking back now, it may seem obvious that Derek Pratt and George Daniels would become friends. The two top watchmaking talents of their generation, both were born in England, 12 years apart. According to Treffry, “the two would have long phone conversations every Sunday discussing at length the various challenges they were both tackling in their work that week”.

While they shared a lot of skills and knowledge, they were also able to complement each other nicely. Pratt’s skill in machining, specifically Electrical Discharge Machining (EDM), was of great help to Daniels, and it is believed that Pratt machined the small pinion needed to create the thin co-axial escapement.

George Daniels with Derek Pratt and Grahame Brooks, the then UK Sales Director for Audemars Piguet, in 1986 in front of Daniels 1928 “Blower Bentley', courtesy of Grahame Brooks.

This wouldn’t be the only part that Pratt would play in the life and success of the co-axial. Daniels would rely heavily on Pratt’s language skills – he was fluent in Swiss German and could get by in French. Having not only a reasonably competent speaker on his side, but one who fully understood the intricacies of what they were trying to explain, helped him negotiate with the various brands to get his invention commercialised.

There have been parallels made between Pratt and Daniels, with fair reason. Both were more than capable of making incredible watches of an often-unmatched quality from start to finish, machining each component not only to perfect functionality, but also in a way that was visually pleasing. As Treffry says, “Certainly [Pratt was] on a par with Daniels in skill, but very different in objectives. I think Derek was an amateur in the highest sense of the word; he loved what he was doing.”

Their shared interests didn’t stop at watchmaking. Like many who are engrossed by traditional watchmaking, both Daniels and Pratt loved mechanisms of all shapes and sizes. While Daniels is well known for his love of vintage cars, especially Bentleys, Pratt’s motorising passions stemmed from one of his horological breakthroughs. He had a passion for Mazdas driven by Wankel engines which made use of Reuleaux triangles, a curved shape with a constant width, which Pratt utilised in his remontoire system. It wasn’t just machines that excited Pratt – he also found great enjoyment in pop-pop boats, a small toy that can be made at home using pretty rudimentary parts. Pratt would perfect these, wonderfully over-engineering them by adding radio-controlled steering, and wrote multiple articles about them.

Pratt racing on what is believed to be a BSA Sloper, courtesy of Derek Pratt: Watchmaker (BHI, 2012).

On a slight tangent, Pratt’s love of all things horological was not limited to pocket watches and wristwatches – he had a great fascination with Gothic iron clocks that still run in so many European village clock towers today. He would also produce four water clocks over the duration of his career. It’s an aspect of horology that not many think about today, and possibly not the most attractive side of the industry, yet it’s one that intrigued Pratt. One that he made and would continue to develop for years stood over two floors in his workshop and now resides at the BHI Museum in Upton Hall, Nottinghamshire. His third water clock was a commission for a village celebrating its 950th anniversary, taking the role of part public art, part functioning timekeeper.

While these two British master watchmakers were very similar in a lot of ways, it is perhaps their differences which affect their separate legacies. Daniels was known for being a force of nature in the industry: nothing was going to get in his way of making the co-axial a commercial success, nor would he stop constantly pushing to promote English watchmaking and the Daniels Method. Meanwhile, Pratt was very happy to work under the name of others. “He was quiet; mild-mannered in a very low-key way,” says Richard Stenning, co-owner of Charles Frodsham & Co.

Certainly [Pratt was] on a par with Daniels in skill, but very different in objectives. I think Derek was an amateur in the highest sense of the word; he loved what he was doing.

Timothy Treffry

Treffry pointed out to us that Pratt and Daniels’ origins differed a huge amount, which seemed to affect how they would pursue their watchmaking. “[George] started out in poverty and fought his way up step by step… Derek came from a happy middle-class family and was supported in the hobby which became his career. As long as he could make a decent living and could more or less do what he wanted, he was content.”

Constantly in work, he was able to lend his talent to any mechanical project that came his way. This is also possible to see in the way he treated those around him. “He always had time for anyone who might need his help or advice,” Stenning told us.

Whenever Pratt made it over to the UK, according to Stenning, he always had time for the Frodsham team. In fact, it was on one of these visits that Pratt would help inspire them with the development of their wristwatch. “We were working on utilising a spring détente in a wristwatch, but overcoming the inherent issues of such an escapement in a wristwatch was proving difficult,” explains Stenning. “We were in the workshops with Derek chatting about the problems encountered with single-impulse escapements when he pulled out of his pocket the tourbillon watch that he had created for the Breguet competition. He suggested that if we could miniaturise the escapement, it might be the solution.”

This far more stable configuration would lead the Frodsham team to develop the double-impulse chronometer wristwatch that they are making today. We will talk in more depth about Pratt’s double-wheel tourbillon pocket watch further down.

Escapement Development

While Daniels is known throughout the watchmaking community for his co-axial escapement, Pratt also developed an ingenious form of escapement that pulls direct inspiration from the work of A.L. Breguet. This was, of course, his remontoire tourbillon, which held a détente escapement. It would be possible to dedicate an entire article to this, and we might do so at a later date, but we will do our best to describe what is an incredibly complex mechanism in the space we have here.

In 1981, Pratt set to work on solving a problem that Breguet was not able to remedy – providing constant force to a tourbillon. As Andrew Crisford an expert on British watchmaking and Breguet, points out in his memorial in the BHI book, Breguet had attempted this in a couple of watches in which he had engraved “Echappement à force-constanté”, yet there is only one of these watches surviving, and it has since had its escapement replaced “due to the unsuitability of Breguet’s constant-force escapement for use in watches”.

The mechanical principles behind the escapement, courtesy of Derek Pratt: Watchmaker (BHI, 2012).

Pratt’s solution was to incorporate a remontoire inside the tourbillon. This remontoire is what drives the tourbillon and is directly driven by the gear train. This means that the escape pinion that normally drives the tourbillon around the fixed fourth gear is replaced by the pinion attached to the remontoire. This one-second remontoire is attached to the escape wheel via the remontoire spring, which, as the name suggests, winds and releases every second, providing an impulse to the escape wheel.

The component of this construction that stands out more than most is the Reuleaux triangle. This curved equilateral triangle acts as a cam here, controlling the movement of the pallets that stop the remontoire wheel. Attributed to 19th-century German mechanical engineer Franz Reuleaux, the Reuleaux triangle is part of the Reuleaux polygons which all share the unique quality of having a constant diameter. This allows the tines of the fork in which it sits to remain in constant contact with the cam as it rotates and shifts the pallets with each rotation. This is the same shape that’s used by Mazda in their Wankel engines, as mentioned above.

The Reuleaux system, courtesy of Derek Pratt: Watchmaker (BHI, 2012).

This escapement first appeared in a series of pocket watches made for Urban Jürgensen. Pratt would go on to produce a second series of these pocket watches in the 1990s, the main difference being that the triangular cam was made of a synthetic ruby rather than steel, allowing for far lower friction.

In 1997, Pratt would turn his attention to a new project with a new innovative escapement. This time, he would take inspiration from Daniels and his double-wheel design, and construct a watch that incorporated this into a tourbillon that also made use of a détente escapement. In a Daniels double-wheel escapement, the two wheels turn in opposite directions, which is slightly counterintuitive for a tourbillon. According to Treffry, Pratt “came to a realisation while on the loo that if you add a second fixed wheel with inward facing teeth, it would drive the escape wheel rotating in the opposite direction”. Pratt made this watch for a competition celebrating the 250th anniversary of Breguet’s birth. Combining two of the old masters’ inventions, it managed to come second, and would go on to provide some of the inspiration for Frodsham’s Double-Impulse Chronometer escapement. This watch is now on display in The Science Museum in London.

His Unfinished H4

In a previous article, we covered Pratt taking on the Herculean task of replicating H4, the final marine timekeeper produced by John Harrison, famous for beating the Longitude Challenge. This was somewhat of a passion project for Pratt, who had been fascinated by this piece for years, along with Harrison’s full catalogue of work.

Treffry tells us that you could not call Pratt’s chronometer a replica. “He would always say he was ‘building another one’,” he says. “He wanted to get into the mindset of Harrison to try to solve the problems that he had to solve.”

It was also important not to call it a replica because, at the time, H4 was technically owned by the admiralty and was a state secret. This meant that no one was allowed access to it, bar those who worked at the museum in Greenwich – and at the time, the only man trusted to keep H4 running was Jonathan Betts, Curator Emeritus at the Royal Observatory, Greenwich.

This would turn out to be Pratt’s final project. He started it in 1997, but would have to hand it over to the team at Frodsham to finish it. “It was quite a long hand over,” says Roger Stevenson, a now semi-retired watchmaker at Frodsham, who, along with Philip Whyte, travelled to Switzerland and stayed with Derek for a week to start the transition of the project. “He had put so much time and effort into this thing and it must have gradually dawned on him that he wasn’t going to be able to see it through.”

“[Pratt] had put so much time and effort into [the H4] and it must have gradually dawned on him that he wasn’t going to be able to see it through.”

Philip Whyte

The visit by Stevenson and Whyte was not the first contact that Frodsham had had with this project. According to Stevenson, Whyte had put Pratt in touch with the various craftsmen that helped with the specialist parts of this project. Martin Matthews made the silver case; Charles Scarr completed the intricate engraving work; and Jos Houbraken worked on the delicate dial. Something that was impressed on us by Stevenson was that this was the definition of a team effort. However, Treffry pointed out that all of these external craftsmen still had to live up to Pratt’s lofty expectations. “I think he went through three dial makers before he found Houbraken,” he said.

Pratt was very much a perfectionist. In his memorial to Pratt in the BHI’s book, Whyte details how it wasn’t just the dial maker that saw multiple iterations – Pratt also went through multiple casemakers and engravers to ensure that every detail of his H4 would be perfect.

The H4 case and the completed movement in 2014, courtesy of Charles Frodsham & Co, London.

Frodsham officially took control of the project in 2009, shortly before Pratt lost his life to prostate cancer. They were able to complete the project in time for a travelling exhibition called Ships, Clocks, and Stars at the National Maritime Museum at Greenwich in March 2014. “We naively thought we would only have to set aside one day a week to work on H4,” says Stevenson. That one day turned into nearly every waking hour as the deadline approached.

There was one final project which Pratt started and was not able to see complete: the miniaturisation of his remontoire into a wristwatch. He began this project with the American watchmaker Stewart Lesemann. Pratt was able to examine the initial straight-line prototype of this movement, which Lesemann had worked on, before he died.

Pratt's Legacy

It’s safe to say that Derek Pratt was one of the most important and accomplished horologers of the 20th century. His work spans the wide range of watchmaking, and his skills and interests were so varied that he was clearly able to turn his hand to nearly anything mechanical. However, to those that knew him, this was always secondary to his kind and giving nature. “No matter who you were, Derek always had time to sit down and share some advice with you,” says Stenning when remembering the many times Pratt would stop by the Frodsham workshop before heading to the pub for the obligatory ’pie and a pint’.

Pratt being awarded the Tompion Gold Medal of the Worshipful Company of Clockmakers for excellence in horology in 2005, courtesy of Derek Pratt: Watchmaker (BHI, 2012).

While he never took on an apprentice – according to Treffry this was in part due to his incredibly high standards and the fact that he only ever worked off rough sketches and what was in his head – Pratt was clearly very keen to pass on his knowledge whenever he could. He would regularly invite students from WOSTEP to visit his home workshop on Saturday afternoons when, as well as acquiring high level horological knowledge, they would be treated to a substantial afternoon tea created by Pratt’s second wife, Jenny. He was the recipient of multiple awards for his watchmaking, from both the Silver and Gold medals, the second and first highest honours that can be awarded by the BHI, to the Gaïa Prize. He was also a rare recipient of the Worshipful Company of Clockmakers’ Tompion medal.

Many of Pratt’s greatest innovations never made it into the commercial space like the co-axial did. In part, this was because Pratt never pursued this route, but also their high level of complexity made them tricky to produce at scale and almost impossible to scale down to a wristwatch. This often makes his legacy a hard one for many collectors and enthusiasts today to connect with.

Pratt's legacy: a watchmaker whose work was incredibly traditional and complex, taken in 1990, courtesy of Derek Pratt: Watchmaker (BHI, 2012).

Pratt was a rare breed in watchmaking: a hyper-talented watchmaker who seemingly approached all disciplines of the profession at the highest level. As Stenning puts it, “He was the consummate horologist.” Driven by his passion and less by recognition, we wonder how Pratt would have developed in today’s market, where the path to becoming an independent watchmaker seems extremely well trod.

We would like to thank Timothy Treffry and Richard Stenning for sharing their knowledge and stories of Derek Pratt with us. For those looking to learn more about his life and works, we highly recommend buying the Derek Pratt: Watchmaker book from the BHI.