Wristwatch restoration, servicing and repair

Posts Tagged ‘Zenith’

Zenith Sub-Sea Diver (Zenith Cal. 48.5)…

I still keep a speculative eye on eBay and was tempted by this collection of vintage Zenith Sub-Sea oddments, all listed separately by the same seller.

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Mention the word Sub-Sea to any Zenith enthusiast and the watch that comes to mind is likely to be this gents model which is one of the most desirable vintage Zenith watches. Unmistakably a 1970’s watch from the design alone, both the diver and chronograph models are now highly prized by collectors and can be difficult to find in good condition.

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The ladies Sub-Sea diver in this post is more of an enigma. While ladies watches don’t get the coverage of their male counterparts, there is usually information to be unearthed about them. Not in this case however, as there was no information to be found anywhere about this model – pretty rare then I’d say. 😉

Competition for such a parts jumble is always less than for a complete watch (and especially so for ladies watches), so I was pleased to win all the lots without too much of a battle. Buying a collection like this is always a gamble as nine times out of ten you’ll find that parts are either damaged or missing in every movement and you still need additional parts to finish the project.

As the date is displayed between the 4 and 5 markers on this model it was essential that I won the gold dialled parts movement to ensure that I had at least one movement with the correct date ring. The majority of watches have the date aperture at 3 o’clock which means that date rings aren’t generally interchangeable as they would be out of alignment for a 4.5 date display.

When the parts arrived I was pretty pleased with my haul as the case and bracelet were in near perfect condition and I had almost three complete movements, albeit in varying states of repair. I was still missing a winding stem, second hand and crown, but all in all, not too bad.

I was also pleased to find that the casing ring was still inside the case. Without this the movement can’t be properly secured and I would probably have had to make one as sourcing an original would have been difficult.

The movement in this watch is a Zenith cal. 48.5, a 17 jewel automatic with a beat rate of 28,800 bph. The majority of vintage Zenith movements were developed in-house but this one is based on the ETA cal. 2671, a Swiss high-beat calibre that was first produced in 1971 and is still in production today. The only differences appear to be the mainplate which is stamped ‘48.5’ and the winding rotor which is Zenith branded.

The movement above was the worst of the three which was encouraging as, apart from the broken stem and the tarnished weight on the winding rotor, the rest of the movement looked to be ok. The first job was to disassemble all three movements and select the best parts from what was available. The resulting parts were then cleaned and the rest of the build was handled just like a regular service job.

I rustled up a suitable second hand from my parts stock and a Zenith branded crown in the right size was quickly sourced too, so everything was starting to take shape.

Being an ETA based movement that is still in production, the winding stem was easy to source too so the rest of the job was plain sailing from there, Here’s the result – not bad at all from a collection of parts.

Just after completing the project I was surprised to find another identical NOS (New/Old Stock) dial, hands and case set for sale on eBay, this time in Italy. I was confident that I could still make another good movement from the remaining parts, so I put in my bid again and was pleased to be the only bidder.

As with the first one I was missing a winding crown and stem, but at least I knew where to source them so they were  duly ordered and I started the whole service and rebuild process again… a case of horological déjà vu!

Here they are together.


Zenith Defy Automatic (Zenith Cal. 2552 PC)…

Another Zenith on the blog, this time a vintage Defy.

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The Defy is a long serving model in the Zenith range (the name being an anglicization of the French word “Defi” meaning “Challenge”) and the subject of this post is the first Defy model which was introduced in 1968 at a time when Zenith were looking to break into the sports watch market.

With a screw down crown, hardened mineral crystal, water resistance to 300 metres and built-in shock absorption, it’s clear that the watch pulled no punches in terms of toughness… a terrible segue into this advert there, apologies!

The first model was introduced with a choice of dial colours and additional Defy models were produced during the 1970’s in a variety of case designs.

Opening the watch reveals a Zenith cal. 2552 PC, an in-house 23 jewel automatic calibre with a beat rate of 21,600 bph. (Notice that around the movement is a rubber spacer which acts as the aforementioned shock absorber.)

Only the early watches were fitted with this calibre as from 1971 onwards it was replaced by the cal. 2562 PC and 2572 PC both of which had an increased beat rate of 28,800 bph. You may see “28 800” printed on the dial of some models to reflect this.

The watch arrived in running condition, but the gaskets had deteriorated into a black paste and judging by the condition of the oils, the movement hadn’t been serviced for quite some time.

While the movement showed no sign of corrosion, the gaskets had obviously been in poor shape for a long time as the dial and hands did show some deterioration due to moisture ingress; the lume had discoloured slightly (albeit not in an unpleasant way) and the hands were tarnished.

You’ll often see the word ‘tarnished’ associated with hands and dial markers on vintage watches and it generally refers to the plated surfaces having corroded. Under the microscope you can see that the top layer of the chrome plating has become pitted due to tiny droplets of water sitting on the hands for an extended period – effectively “eating away” the plated surface over time.

There isn’t really much that can be done to improve the finish once this has occurred as most hands are either chrome or gold plated and any attempt to polish out the pitting simply wears through what is left of the plating to the base metal underneath. The only solution is to have the hands re-plated, but that means losing the original luminous filling. In most cases it’s often best just accept the tarnish and polish the remaining plate as much as possible, and that was the preferred option here.

The movement was in good condition and it needed no more than a routine service, and the case too was still in good order and only needed an ultrasonic clean and light buff to restore the shine. The crystal however had a few scratches and chips around the edge which isn’t uncommon for this model as the crystal sits a long way above the bezel and even though hardened, is still susceptible to knocks and scrapes.

As the watch is long discontinued, finding original mineral crystals can be very difficult and often an acrylic aftermarket replacement is the only alternative, but even they can be difficult to source. Thankfully the owner of this watch tracked down a replacement crystal which made my job a little easier this time.

With the movement serviced and the new crystal and gaskets fitted, the watch could be rebuilt.


** Many thanks to Francois Canters for letting me feature his watch on the blog. **

Zenith El Primero A385 (Zenith Cal. 3019PHC)…

A classic chronograph this time on the blog, a vintage Zenith El Primero A385.

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The story of the El Primero is legendary in the watch world. Development started on the El Primero (meaning ‘the first’ in Spanish) in 1962, with Zenith hoping to unveil the first automatic chronograph just in time for their centennial in 1965. Unfortunately things didn’t go as planned and it wasn’t until late 1968 that the first working prototypes were finished. With other manufacturers nearing completion of their own automatic chronograph calibers, Zenith stole a march on their competitors by holding a low-key press conference in January 1969 showing two working prototypes and claiming the title.

However, as production models were not available to the public until October 1969, making them the third manufacturer to market after Seiko and Heuer et al. (in the spring and summer of 1969 respectively), who was actually the first? The debate still goes on, and the whole story is covered in more detail by Jeff Stein’s excellent article, Project 99.

The watch in this post was one of the first models to be released in 1969, along with two other models, the A384 and the A386.

More models were to follow in the early 1970’s, as well as models from their sister company Movado which also used the El Primero movement (I wrote about one such Movado here).

Although still in production today, the El Primero came very close to being “just another discontinued calibre” in 1975, when as a result of the quartz revolution, the Zenith Radio Corporation (the owners of the company at the time) decided that quartz watches were the future and the tooling for all mechanical calibres was to be sold for scrap, by the ton, to the highest bidder.

Needless to say, after a century of producing quality mechanical calibres this decision wasn’t well received by the work force, especially not by manufacturing foreman Charles Vermot who had been involved with the El Primero since its preliminary sketches. Despite his protestations the sale was to go ahead as planned, but in a move that undoubtedly saved the El Primero, Vermot defied the orders from above and evening after evening, began hiding the tooling and presses for the El Primero (numbering 150 in total, many weighing over a ton) in unused recesses of the factory, all the while keeping a record in a ring binder which he hid in the attic.

Ebel bought Zenith in 1978 and were keen to restart production of the El Primero, but how would they do that without the necessary tooling? It was at this point that Charles Vermot stepped forward and admitted to his insubordination – unsurprisingly, he was congratulated rather than punished; the tooling was re-instated, and with Ebel’s help full production of the El Primero started again in 1984.

Charles Vermot

From a technical perspective, the El Primero calibre can be seen as “having it all”; automatic winding, a high beat rate of 36,000 bph (10 ticks per second) making for an incredibly smooth sweep and chronograph accuracy to 1/10th second, an integrated design allowing the watches to be slimmer than competing modular chronographs, and a date with independent quickset via the crown.

Cramming in all that good stuff does make it relatively complicated however – the going side of the movement is pretty ‘busy’, and a peek under the dial uncovers a plethora of parts.

As you may have spotted in the first picture, the watch in this post arrived missing the reset pusher, and there was no sign of life from the movement with the chronograph either engaged or disengaged which was a concern.

On closer inspection, it was immediately obvious that things weren’t right as a number of the components weren’t located properly underneath the chronograph bridge. I can only assume that a previous watchmaker had taken the watch apart, considered the job too difficult and simply screwed the bridge back on again. Miraculously, none of the parts were damaged and all the pivots were still intact. However, my initial relief was short lived when I discovered that the chronograph bridge was now bent. By not locating all the components correctly first, the bridge had been bent upwards when the screws were fully tightened down.

You might imagine that simply bending the bridge back down again would be an easy solution, but once a piece of metal has been bent, the material stretches and it’s very difficult to return it to its former state – try it with a paper clip and you’ll see what I mean. In the world of horology where tolerances are measured in fractions of millimetres, this can have a dramatic effect, and especially so on this calibre where the tolerances are particularly tight.

The good news was that with the winding components removed and the chronograph disengaged, the base movement actually started ticking which was one less concern, but with the chronograph bridge bent back down again and all the components in place, there were still problems with the running of the chronograph and the reset mechanism, plus the automatic winding rotor dragging on the outer edge of the movement.

Making an adjustment to solve one problem had a knock on effect elsewhere, so it took quite some time and patience to get everything working properly. However, my patience paid off and after a full service the movement was fully operational again and looking good.

From a cosmetic perspective, the watch wasn’t too bad. The lume had deteriorated on the dial and had fallen out of the hands completely, so that needed to be replaced. The hour markers had tarnished too over the years, which could be improved but not removed completely.

With the movement and cosmetic work completed, both pushers were replaced with new items to ensure a perfect match, the case was cleaned and the crystal was polished to finish the job.

Finding vintage El Primeros in good condition is not easy these days, so it may interest readers to know that Zenith released a modern re-issue in 2009 under the banner ‘The Originals’, albeit in a limited release of just 500 per model.


** Many thanks to Prashant James for letting me feature his watch on the blog. **

Movado Datron HS360 (Zenith Cal. 3019PHC)…

A bit of a hidden gem this time, a Movado Datron HS360.

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Founded in 1881 in La Chaux-de-Fonds, Switzerland, Movado (Esparanto for “continuous movement”) are primarily known for producing quality dress watches, the most famous being the Museum range. The design is evocative of a sundial with the dot representing the sun at noon. Designed by Nathan George Horwitt in 1947, it was the first watch to be introduced into the Museum of Modern Art, and is still in production today.

The watch in this post is from an interesting period in the company’s history, the late 1960’s/early 1970’s, when the company was owned by the Mondia-Zenith-Movado holding company. Being part of this union allowed Movado access to Zenith’s now legendary cal. 3019PHC ‘El Primero’ calibre – which is found inside the watch in this post, the only difference being that Movado engraved their own name and logo on the winding rotor.

Arguably the first automatic chronograph calibre, the El Primero was first introduced in 1969 and was used in a number of models for each company, some identical models were branded either Movado or Zenith, and some were unique to each brand. In terms of collectibility, the Zenith models seem to be more desirable these days and command a premium, but the Movado models certainly shouldn’t be overlooked.

The HS360 was exclusively a Movado range and there were several different models, the watch in this post being one of the most popular. The early models were branded “Datachron HS360”, though the name was shortened to ‘Datron’ later in the production run.  Here is an advertisement from the early days highlighting the major functions.

The watch in this post arrived in good overall condition, but was desperately in need of a service and was rattling around inside its case due to a missing case clamp. The pushers were also in poor shape and needed to be replaced. There were no other hidden surprises, so after the essential mechanical maintenance, the case was cleaned and the crystal polished to finish the job.

I think this is a great looking watch, and with a top quality movement inside, what’s not to like?


** Many thanks to Tjeerd Jellema for letting me feature his watch on the blog. **

Zenith Surf (Zenith Cal. 2572PC)…

Here is a watch that you don’t see every day, a Zenith Surf.

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Zenith dates back to 1865 when 22 year old Georges Favre-Jacot started the company in Le Locle, Switzerland. At that time, most watchmaking tasks were performed by individual watchmakers working in their own homes, but Favre-Jacot changed all that by bringing all the disciplines together under one roof where they could work together, increasing production rates, and improving quality.

The concept certainly worked and by 1875 the company employed over 1000 people producing pocket watches, pendulum clocks and counter instruments. By 1922, the company had produced 2 million timepieces.

Although Zenith have produced more than 50 calibres and won over 1500 watch industry awards, they are probably most famous for creating the legendary “El Primero” chronograph calibre. It was (arguably!) the first chronograph caliber with automatic winding, and was the only mechanical chronograph with a beat rate of 36,000bph, capable of measuring time intervals to an accuracy of 1/10 of a second. It was, and still is a fine piece of engineering, and is still in production today.

The watch in this post arrived in a non-running state as water had found its way inside the case at some point, and judging by the condition of the movement, it must have been quite some time ago. You can see in the following picture rusted parts and signs of dried water on the winding rotor and caseback. Never what you want to see when you open a watch!

The water had also affected the dial and hands, staining the dial, and damaging the lume in the hands.

When parts have rusted, care has to be taken during disassembly as it is very easy to break the head off a rusted screw, leaving the threaded shaft behind. If the threaded shaft is rusted in place it can be very difficult to remove even with the right tool for the job; Bergeon’s broken screw extractor.

The tool is mounted in a suitable vice and the broken screw in the plate (or bridge) is aligned with the two pins at the top of the tool. These pins are made from hardened steel and have serrated teeth (bottom inset) which cut into the shaft of the broken screw. The pins are screwed firmly into place holding the shaft securely from both sides (top inset) and the plate is then rotated by hand until the shaft is screwed out of the plate.

When a watch is water damaged, it is often a trade off between the amount of time needed to clean up and refinish rusted parts, and the cost and availability of replacing them. Although water had found its way right through this watch, only superficial rusting had occurred on some of the parts so the cleanup was relatively straight forward, and only the two rusted bridge screws for the automatic winding mechanism had to be replaced.

With the movement all cleaned up and running again, the stain was carefully removed from the dial, the hands were relumed, and the case and bracelet cleaned. Here is the result.


** Many thanks to Francois Canters for letting me feature his watch on the blog. **