Wristwatch restoration, servicing and repair

Minerva Chronograph Ref:1335 (Minerva Cal. 13-20)…

Another quality vintage chronograph on the blog, this time from Minerva.

(Click pictures to enlarge)

Minerva was founded in 1858 as “H. & C. Robert” in Villeret in the Bernese Jura by two brothers, Charles-Ivan and Hyppolite Robert. Like many other companies, they started by producing pocket watches built around calibres from other manufacturers until they could establish their own place in the market.

Hyppolite retired in 1880 and as the company continued to grow, Charles’ brother Yvan and sons Charles-Auguste and George-Louis joined the company and the name was changed around 1889 to “Robert Frères Villeret” along with the introduction of a new RFV trademark.

From 1902 onward RFV began producing their own in-house calibres and cases, with their first chronograph and stopwatch calibres being introduced in 1908. The Minerva brand name as we know it today was first introduced in 1923 and the company was renamed to the now familiar “Minerva SA, Villeret” in 1929.

In 1934 Minerva SA was taken over by Charles Haussener and Jacques Pelot and run by Pelot’s nephew Andre Frey. The Frey family retained ownership of the company and production continued uninterrupted up until 2000 when there were big changes at Minerva, but more on that later…

The movement inside the watch in this post is one of Minerva’s longest serving column-wheel chronograph calibres, the cal. 13-20.

The cal. 13-20 was one of the earliest wristwatch chronograph calibres available and was developed in collaboration with chronograph specialists Dubois-Depraz. First produced in 1923 it was originally designed as a mono-pusher chronograph before being changed to a two pusher design around 1940 after which it was available in both 30 and 45 minute variants.

Even at a glance it’s easy to spot the quality in this calibre; the plates and bridges are richly plated, most of the components have polished bevels and it has solid steel return springs throughout. Typical of calibres from this period it has a screwed balance wheel, a Breguet hairspring and it pre-dates any shock mechanism for the balance staff.

Under the dial, with no hour register the calibre is pared down to a minimum, with the set lever spring and minute wheel bridge being combined into one component.

As well as the Minerva ‘arrow in a circle’ on the train side of the movement (pictured inset), the RFV trademark with the arrow is clearly visible here along with a serial number. Under the RFV trademark is the word ‘Depose’ which is short for Modèle Déposé, the Swiss/French for “Registered Design”.

Arriving already in excellent condition both mechanically and cosmetically, the movement needed no more than a routine service and a new mainspring this time.

At 36mm it’s quite a small chronograph by modern standards but the design has certainly aged well. There’s no denying that with its blued cathedral hands and minimal dial markings, this is a handsome watch.

A testament to the quality of the cal. 13-20 is the fact that is was produced almost unchanged from the 1940’s and was still being manufactured on the original production machinery until 2000. At that time the Frey family sold the company to an Italian investor, Emilio Gnutti, who radically changed the working practices and the future for the whole Minerva brand.

It was decided at that time that the current Minerva calibres could not be reproduced using modern machinery so they were re-engineered in CAD for CNC machining. The 13-20 was effectively retired at that point and the redesigned calibre was named the cal. 13-21 to reflect the updates. As you can see below, using modern production methods and hand finishing techniques the quality of the resulting calibre is clear to see.

Interestingly, the calibre was returned to the original mono-pusher design before the subsequent development of a two pusher version, the cal. 13-22.

Powered by updated calibres the Minerva brand was effectively relaunched into the Haute Horlogerie segment with a range of new models. Sadly their rebirth was relatively short lived as Minerva was bought by the Swiss luxury goods company Richemont in October 2006 and was assigned to the Montblanc brand where it remains today.

Minerva branded watches are no longer available and Minerva’s technical team are now responsible for producing the hand crafted calibres found in other Richemont brands, predominantly the Montblanc 1858 Villeret collection and more recently in a small number of Panerai chronographs.


** Many thanks to Daniel Spiegel for letting me feature his watch on the blog. **

Season Greetings…

‘Tis the season and all that good stuff! A Merry Christmas to all readers and best wishes for a happy and healthy 2018.

Enjoy yourselves!


Favre-Leuba Twin Power (FL Cal. 259)…

I’ve worked on quite a few of these watches over the years but never written about one, so let’s have a look at this Favre-Leuba Twin Power.

(Click pictures to enlarge)

With one of the longest histories in watchmaking, dating back to 1737, Favre-Leuba introduced some interesting technical innovations into their watches and especially so during the 1960’s. During that decade they produced the first watch with a built in altimeter, the Bivouac, a depth meter in their Bathy diver and they were among the first companies to produce in-house high-beat calibres for their Deep Blue divers and Sea Raider models. (I’ve written about the latter two watches in the past, click here and here respectively if you would like to read about them.)

The watch in this post, although quite plain compared to some of the recent watches on the blog has enough going on inside to deserve a mention.

Inside is a Favre-Leuba cal. 259, a 17 jewel, in-house, manually wound calibre with a beat rate of 18,000 bph. Derived from the FL cal. 251 which was first introduced in 1962, the cal. 259 featured some technical improvements and also added a date function.

What makes this calibre interesting and gives it its “Twin Power” moniker is that is has not one but two mainspring barrels. While two mainspring barrels isn’t that unusual these days, they are often placed in serial to significantly increase the power reserve of a manually wound watch. The Nomos Lambda is one such example that comes to mind, a manually wound watch with a power reserve of 84hrs (3.5 days).

What made the Favre-Leuba calibre unique in 1962 was that it placed the mainspring barrels in parallel, meaning that both barrels were wound simultaneously and both provided power to the centre wheel. With the winding bridge removed you can see that both barrels transfer their power to the centre wheel via an intermediate wheel mounted on the mainplate.

The benefit of this method is that drive is balanced between the two barrels, ironing out any power fluctuations which results in a more constant power delivery through to the escapement and a more stable rate.

A secondary benefit is that as each mainspring only needs to deliver half of the power required it is much thinner and can therefore be longer, resulting in a power reserve of 50hrs which was more than most watches were offering in the early 1960’s.

Here is a picture of the two barrels and springs when disassembled. Interestingly, the design of the barrel unifies the barrel arbor and ratchet wheel into one part so both parts reside underneath the winding bridge resulting in a thinner calibre (3.1mm) and an uncluttered aesthetic.

As the barrel design has no cover, additional care must be taken when greasing the mainsprings on these calibres as any excess could creep out and contaminate the rest of the movement.

The underside of the winding bridge has the click spring and three intermediate winding wheels mounted onto it to allow both barrels to be wound from the crown simultaneously.

Though the watch was in decent cosmetic condition on arrival it was a poor runner and had a problem with the date function. When looking over the movement I spotted that there were some marks on the train bridge and under the microscope this is what I found…

A service mark from February 1991. You often see service marks scratched into the caseback which is bad enough but why any watchmaker would do that directly onto a bridge I’ve got no idea…. if this was horological X-Factor it would get three “No’s” from three me’s!

The date issue was resolved with a new jumper spring and rest of the service was straight forward, so with the dial, hands and case cleaned and the crystal polished, the watch could be rebuilt.

Although not specifically branded in this case these watches can often be found with Twin Power engraved onto the movement and/or printed on the lower half of the dial. Twin power movements can often be found in Favre-Leuba’s Sea King and Sea Chief models too.

However, care must be taken when buying any of these models as they were made in significant numbers and now seem to be popular with sellers in India or SE Asia who reprint the dials (often in lurid colours) in an attempt to freshen up what are in truth tired examples. Sadly this practice has somewhat tarnished the reputation of the brand, but with care all original examples can still be found.

… and finally, since the rebirth of Favre-Leuba in 2006, an updated version of the Twin Power calibre has been developed, the cal. FL-401 which debuted in 2009. I use the term “updated” loosely in this case as the only thing it shares with the original is the parallel twin barrel concept. The new calibre runs at 36,000bph and has a power reserve of 8 days (192 hrs) which is quite an upgrade on the original.


** Many thanks to Tony Wright for letting me feature his watch on the blog. **

Heuer Skipper Ref. 15640 (Heuer Cal. 15)…

It’s been a few years since I’ve written about a sailing timer on the blog, so let’s have a look at this Heuer Skipper.

(Click pictures to enlarge)

Heuer’s first Skipper model was released in 1968 and is now known as the ‘Skipperera’ among Heuer collectors due to be it housed in a Carrera chronograph case. The Skipperera is an incredibly rare watch as it was only produced for a year or so and there are only thought to be around 20 known examples in collections today.

The second iteration was introduced just year later in 1969 and was based on the popular Autavia ref. 2446C. The watch featured an oversized 15 minute subdial and the calibre inside was a modified Valjoux cal. 7730.

From 1971 onwards production moved on to the Autavia case, the earliest models based on the then current Valjoux 7734 powered chronographs (recognisable by the crown and pushers all being on the right) and the later iterations were built around the Heuer cal. 15 automatic. The watch in this post is one of the earlier cal. 15 models, known as the 1st generation ref. 15640, recognisable by the blue dial and glossy blue bezel insert.

The other Autavia cased iterations are pictured below, clockwise from the top left; the Valjoux 7734 powered ref. 73463; the earliest cal. 15 based Skipper, the ref. 1564, fitted with an acrylic rather than mineral crystal and slightly different case details; the early black ref. 15640 made between 1978 and 82 and finally the late black ref. 15640 made from 1983 until 1985/6.

For a complete history of the Skipper and Heuer’s other sailing timers, check out Henrik’s excellent site HeuerChrono.com.

According to the owner, the subject of this post had spent a good few years in a drawer – sliding around face down by the looks of things as the mineral crystal was completely scratched up. (Thank goodness that the crystal protrudes above the bezel insert on these models or that too would have suffered the same fate and wouldn’t have been nearly as easy to replace.)

Under the damaged crystal everything was in good original condition. The watch was running which is always a good start but as the subdial hand was off and floating around the dial, it was hard to say if the sailing timer was fully functional.

The owner and I were hopeful that the hand had just come away from its post but on disassembling the watch the reason the hand was loose was immediately obvious. The shaft of the minute recording runner had broken clean off at the base.

The good news is that the minute recording runner is shared among all the Heuer 12, 14 and 15 calibres but that isn’t the case for the wheel onto which the sweep second hand is mounted, the central chronograph runner, which is unique to the cal. 15 Skipper movement.

As you can see when you look at any Skipper the minute subdial only has 15 minute graduations opposed to the 30 seen in a traditional Heuer Autavia chronograph.

This is of course required specifically for the 15 minute countdown at the start of a yacht race and to implement this Heuer adopted the same system as the Valjoux cal. 7737 used predominantly by Memosail (an example here), namely two fingers on the chronograph runner instead of one.

In operation this effectively moves the minute recording runner forward every 30 seconds rather than every minute, very simply transforming the mechanism (and subdial) from a 30 minute to a 15 minute counter.

Thankfully the centre chronograph runner was in good condition as I’m told that it’s now an incredibly difficult part to source. Even though the minute runner should have been a relatively common part, as Heuer parts are getting harder to source these days I needed to call out to the Heuer community to help me find one. Needless to say they came through for me once again and things were quickly back on track.

With the minute runner replaced and the base movement serviced, the rest of the build was straight forward. The chronograph module and the rest of the watch was rebuilt, the case cleaned and a new crystal fitted returning the watch to full working order.


** Many thanks to Richard Perry for letting me feature his watch on the blog and to James and Gianluca for helping me out with the minute runner. **

Enicar Sherpa Graph (Valjoux Cal. 72)…

Another Valjoux powered vintage chronograph on the blog, this time it’s an Enicar Sherpa Graph.

(Click pictures to enlarge)

I’ve written about a Sherpa model in the past, the Sherpa Dive but the Sherpa Graph is a stalwart of the range and is now very popular with vintage watch collectors.

First introduced in 1960 the Sherpa Graph went through many changes during its production run and was made with a variety of dial and hand combinations. Changes were also made to the dial and tachymetre bezel over the years, so with such a wide range of variations it can be difficult to accurately date a Sherpa Graph.

The earliest model had lumed sword shaped hands and similarly shaped subdial hands. Only a handful of these are thought to exist so you’ll be very lucky to find one these days.

Production moved quickly to the paddle shaped hands that you see on the watch in this post and over the next few years watches were produced with white, silver and black dials. By the late 1960’s models were being produced with more substantial baton shaped hands though still with an array of chronograph hands combinations.

Here are a few of the model iterations.

For more comprehensive coverage of the topic I’d recommend checking out this excellent Collector’s Guide from the website TheSpringBar which gives a full overview of the Sherpa Graph and Enicar’s other Graph models.

Getting back to the subject of this post it’s worth spending a few minutes describing the case on this watch as it isn’t a typical screwback as you might expect. All of Enicar’s Graph model watches used the Super Compressor case designed and patented by Ervin Piquerez S.A (EPSA).

Super Compressor cases were made by EPSA from the 1950’s until the 1970’s and were used by many watch manufacturers including Longines, Jaeger-LeCoultre, Hamilton, Lip, Benrus, Universal Geneve and Tissot to name just a few.

Turning the watch over the caseback has some nice decoration in the centre, “Sherpa 300” in script (300 being the water resistance in feet) and a picture of an oyster with a pearl, denoting the ‘Seapearl’ for which Enicar are also well known.

With the caseback removed you can see two of the three “loops” of thick wire protruding from the inside of the case…

…and on the inside of the caseback are three corresponding raised sections, each with a protruding lip on the outside.

When the caseback is placed inside the case in the correct orientation and turned through 75 degrees, the lips on the caseback hook under the wire loops securing the caseback in place. Simple but effective – though it can still catch out anyone who is unfamiliar with this type of case construction.

The watch arrived in running condition but with a few cosmetic issues to address. Moisture had found its way into the case, most probably via the edge of the crystal and had rusted the hands. Rust had also permeated the crystal itself, the evidence of which you can see over the ‘M’ in ‘Tachymetre’ in the first picture. As with this Dodane that I wrote about a couple of years ago, when an acrylic crystal ages, it shrinks and small cracks form in the body allowing rust and dirt to creep up into the acrylic and stain the crystal. A replacement is the only option in such cases.

With the watch out of the case the extent of the rust on the hands was clear to see. The main hands had tarnished on the shafts and around the lume plots and the subdial and sweep hands had also been affected. Thankfully the dial had not been damaged and the original lume and paint was all still intact.

The first step was to carefully remove the hands and put a layer of clear binder on the back of the hour and minute hands to secure the lume. The next step was to carefully scrape away all the surface rust which requires a very steady hand as one slip into the lume or paint and it would surely break away.

As mentioned in previous restorations, it isn’t possible to remove the surface pitting in the chrome plate once rust has set in but with care decent results can still be achieved.

The movement inside this watch is the ever popular Valjoux cal. 72. The one in this watch, although it hadn’t been serviced for some time, was still in good condition and needed no more than a routine service this time.

So with the movement serviced and the cosmetic issues addressed, the case was cleaned and a new crystal fitted, after which the watch could be rebuilt.

A quick side profile shot shows that this watch still has its original crown, cross hatched as is typical for most EPSA Super Compressor cases but also branded with the Enicar logo too.

This style of crown was only used on the later Sherpa Graph models, the earliest ones simply had a plain cross hatched crown. It’s a small detail, but well worth noting when you’re looking for original features.


** Many thanks to David Pearce for letting me feature his watch on the blog. **

Fortis Centinela Alarm (Venus Cal. 230)…

It’s been a while since I’ve written about an alarm watch on the blog, so let’s have a look at this Fortis Centinela.

(Click pictures to enlarge)

Fortis was founded in 1912 in Grenchen by Walter Vogt who had developed his watchmaking skills whilst working for Eterna. Probably best known for their modern Flieger and aviation inspired chronograph watches, Fortis have an interesting vintage history which included working with English watchmaker John Harwood on the development and release of the first ever automatic watch in 1926, developing the first waterproof alarm chronometer in 1956 and the first Swiss made plastic cased watch, the Flipper, in 1967.

The watch in this post is something of a ground breaker too as it was Fortis’ first ever alarm watch. Introduced in 1954 the Centinela had a production run of just 2 years before being replaced by the less complicated, A.Schild Cal. 1475 powered Manager model, making the Centinela something of a rarity.

Turning the watch over the caseback is unusual as it has a number of holes in it, effectively creating an echo chamber for the alarm…

… and under the screwdown outer caseback is a sounding plate with a pin mounted on the inside which is struck by the alarm hammer, causing the plate to resonate when the alarm is ringing.

Inside the watch is a Venus cal. 230, a 21 jewel, manually wound alarm calibre with a beat rate of 18,000 bph.

The watch arrived in non-running condition and the reason was immediately obvious. As you can see above, the ratchet wheel screw had sheared off inside the barrel arbor and the ratchet wheel was rattling around inside the case.

The Venus cal. 230 is an unusual alarm calibre as it only has a single mainspring barrel powering both the alarm and the going train. The calibre also has an uncommon dial aperture showing the alarm state; green for on, red for off.

In operation, the crown at 3 winds the mainspring and sets the time and the crown at 4 is used to set the alarm time and to enable/disable the alarm.

Let’s have a look at how it works…

When winding the watch the first four complete revolutions of the barrel arbor set up the power source for the alarm. Under the ratchet wheel is the alarm stop wheel which controls the release of power when the alarm is triggered. When fully wound the missing teeth in the stop wheel allow the arbor/mainspring to be wound further to power the going train. The alarm stop wheel also acts as the click in a regular watch preventing the mainspring from unwinding.

When the alarm is triggered, power is released from the arbor end of the mainspring until the alarm stop wheel reaches its unwound state; a very clever way of powering the alarm as the going train continues to run while the alarm is sounding. It does however have an effect on the overall power reserve, the alarm sounds for 10 seconds which costs around 12hrs of reserve. The reserve and alarm can of course be topped up again by winding the watch.

When the alarm is triggered the ratchet wheel rotates counter-clockwise, transferring power through the intermediate and alarm wheels to the alarm hammer which rocks back and forth, the two pins on top striking the pin in the sounding plate on the case.

This calibre is also reasonably complicated under the dial. With the top plate removed you can see the alarm setting wheels and the green and red painted sections on the alarm bolt yoke which are visible through the dial aperture.

The release mechanism works the same way as the Seiko’s Bell-Matic calibre in that the unlocking wheel has three cut-outs which correspond to three raised sections on the hour wheel as seen below.

When the raised sections and the holes in the unlocking wheel align (in other words, the alarm time is reached) the hour wheel rises along with the disconnecting lever underneath, freeing the alarm hammer on the other side of the movement, releasing power from the mainspring and sounding the alarm as detailed above.

Aside from the sheared off ratchet wheel screw, the shaft of which was stuck fast inside the barrel arbor resulting in a replacement arbor being needed, the rest of the service was straight forward, so once the case had been cleaned and a new crystal fitted, the watch could be rebuilt.

At 38mm this is quite a large watch, especially for the 1950’s. It wears well and would make an interesting addition to any collection, the hard part may be finding one.


** Many thanks to Kevin Fuller for letting me feature his watch on the blog. **

Seiko 5246-6000 (King Seiko Special Chronometer)…

At the top of the King Seiko food chain and with enough dial text to rival a modern Rolex, Seiko made it obvious that they were ticking all the boxes with this 5246-6000 Special Chronometer.

(Click pictures to enlarge)

As many enthusiasts will know, Seiko’s vintage watches were produced by two wholly owned subsidiaries; Daini Seikosha Co. and Suwa Seikosha Co. During the 1960’s and early 70’s the two companies were competing to produce Seiko’s flagship models and although both companies produced watches for all segments of the market, the competition was most evident at the ‘prestige’ end of the market where technological development and accuracy were key factors.

In December 1960 the Suwa factory released the first Grand Seiko model, realising their long held ambition to produce a chronometer rated timepiece that exceeded the recognised standards of the Official Swiss Chronometer Testing Institute, the Contrôle Officiel Suisse des Chronomètres (COSC).

In response the Daini factory released the first King Seiko model in 1963, but without a chronometer rating it was deemed inferior to the Suwa Grand Seiko.

What it did do however was spark a rivalry between the two companies which would see the development of some outstanding high-beat manual and automatic calibres which were undoubtedly the pinnacle of their output prior to the quartz revolution.

For a more in-depth overview of the Grand and King Seiko models, check out this excellent two part series written by Evan Yeung for the online watch magazine Monochrome.

The subject of this post is arguably the best watch that the Daini factory produced, but before getting into what’s inside, let’s have a closer look at the case. Turning the watch over you immediately know this is an unusual model as it is completely smooth; no caseback or medallion, just a simple KS logo, model number and opening instructions.

Between the lower lugs is a screw to allow for fine regulation but more on that later…

To open the watch the bezel has to be levered off and the crystal and gasket removed. The mineral crystal is mounted in a stainless steel ring which slots into the gasket and the bezel compresses the two to form a waterproof seal.

When removed, a pin or small screwdriver is then used to press down the lever opposite the 4 marker on the dial and the stem and crown can be pulled out.

A casing spring holds the movement securely in the case which has to be rotated before the watch can be from the case.

Inside is the Seiko cal. 5246A, a chronometer rated 25 jewel automatic movement with a beat rate of 28,800 bph. The calibre can also be hand wound and has quickset functions for both the day and date via the crown.

The architecture is unique to the 52xx family, it shares no parts with other lines. The automatic winding mechanism is typical of the higher end Daini calibres using a roller system rather than the magic lever used on lower quality calibres and there are also diafix installations on the escape and third wheel pivots to prevent oil contamination and promote a more stable rate.

Like all other 5 series calibres, under the dial is a raft of parts making up the calendar mechanism and keyless works. Over-engineered? Possibly.

One last thing to cover is the micro-adjuster mechanism which I alluded to earlier. On the outer edge of the movement is a regulating lever and a screw with an eccentric centre section used to provide fine regulation without having to remove the watch from the case.

The screw between the lugs is removed from the case and a small screwdriver can then be used to rotate the regulating screw, sliding the connected lever either left or right to increase or decrease the rate of the watch. A very useful feature.

Having worked on the majority of Seiko’s vintage calibres I can say that this one is certainly on a par with any of the Grand Seiko calibres and this watch would be a worthy addition to any vintage Seiko collection. The hard part may be finding one as they rarely come up for sale these days.

The movement needed no more than a new mainspring and a routine service this time, so with the case cleaned and the watch rebuilt it was soon back in full working order.


Zodiac Automatic Chronograph (Zodiac Cal. 90)…

Following on from the Hamilton Chrono-Matic last month, it’s another Calibre 12 powered automatic chronograph, this time from Zodiac.

(Click pictures to enlarge)

I wrote about this model back in 2010 and at the end of the post I expressed an interest in owning one some day (that post here). I was contacted through the blog by a seller in Germany who was looking to move the same watch on and had found my post when researching the model. A deal was quickly done and the watch was soon inbound.

On arrival I was pleased as the watch was running, the chronograph worked and it was in good overall cosmetic condition. It had a few marks and scrapes from its 40 years of life and was long overdue a service, but all-in-all it was an honest example.

As regular readers and vintage chronograph enthusiasts will know, these chronographs along with models from Hamilton, Clebar, Tradition and Le Jour are known as “Poor Man’s Heuers” because even though they were produced by Heuer, they can usually be bought for less than their Heuer branded counterparts.

Other models in the Zodiac range during the 1970’s were identical to their Heuer siblings in all but the dial print, a few examples being the Zodiac Autavia, Carrera, GMT and they also offered a model reminiscent of Hamilton’s Fontainebleau chronograph.

Though the model in this post was exclusive to Zodiac, it does share the case and movement with the Heuer Jarama (…thankfully the gold coin-edge bezel was omitted from the Zodiac!)

This Zodiac was also produced with two subtly different dial designs; one with red highlights in the left sub-dial and one without. They were also produced with both round and fluted pushers at different times during the production run.

As the watch arrived in relatively good condition, it needed little more than a good clean, a movement service, a crystal polish and some light work on the case to bring it back up to scratch.

Also included in the sale were the original bracelet, box and owners manuals which are always a bonus for any vintage watch enthusiast.