The Zen of Watch Maintenance

Sinn 356 on left, and on right the Seiko SNA139 at 8% of the price. Aside: if you are looking for a dramatic instagram-esque watch photo, liberally apply large-radius unsharp mask to images for more 3D pop. (image of 356 from Worn and Wound http://wornandwound.com/wws-guide-watches-40mm-part-2/)

You don’t need a watch any more, but you may want one because of what it represents — a self contained universe of design thinking and craftsmanship that solves a problem that has been solved many times before, but in its own unique way.

A traditional watch is a reminder that not everything has to be ‘smart’ — buzzing you with notification. Its job is passive: reminding you that time is being spent on your own terms.

It is also a personal statement of what you hold important about style and function. People can really want a particular piece — some people spend thousands on them. There is no practical reason aside from the art and engineering. The community of people that appreciate them is diverse and global — it is a great way to strike up a conversation: “Hey is that a Damasko DS30?”.

Vintage watches have a story, manufacturers have a pedigree, and certain styles like Pilot or Diver are interpreted by each manufacturer with their own unique twist. Some models have been on sale for 50 years.

Traditional watches are subject to modification repair. Unlike a Smart Watch, they are not quite so impenetrably monolithic. As a result, some people would rather customize or repair a watch than purchase a new one. It is another chapter to add to the story of a particular watch.

The book Zen and the Art of Motorcycle Maintenance, whose title is modifed for this article, focuses on Quality. It is an undefinable measure that can only be experienced. The book refers to Dynamic Quality over Static Quality, i.e. the Value of Doing versus the Value of Having. I chose the value of the experience of repairing a watch over the more traditionally measurable quality and value of a high-priced new one.

Choosing between Engineering and Engineering

Sinn on the right, Seiko on the left. Mechanical versus quartz; luxury versus consumer-grade. Like most experiences, there is a point where the incremental differences in utility are decreasingly apparent unless you are a student of the topic.

I liked the Sinn 356 Flieger. It is almost CAD$3000. It uses a hyper-intricate mechanical movement with sand-grain-sized ruby bearings and dozens of moving parts — no battery, no microchip, just extreme mechanical cleverness. It is made of special shot-hardened steel that has a special name. It has a nice German heritage story and excellent Brand Management. It is one order of magnitude too expensive for comfort.

But watches tend to play to a theme. Flieger (Pilot) watches like the Sinn have standard layouts and fonts and other design cues that are common between brands, just like impressionism is a style common to a group of artists.

I liked the look of the Seiko SNA139. It is a Flieger, like the Sinn 356, and is one of the first made of titanium which gives it a similar look to the Sinn. It runs on a $40 quartz movement that shamelessly leverages a battery, microchip and simple single pole stepper motors. It’s an order of magnitude cheaper, and order of magnitude more accurate. And titanium is very interesting when you see it in person, just like shot-hardened steel.

For an excellent rundown of what makes watches tick, and why mechanical and quartz vie for the luxury and consumer market, Secret Life of Machines has a great 25 minute video:

The Seiko also shows time in two timezones (another clock face in a tiny sub-dial). When you program for a living across multiple servers and clients, it is very nice to know what time it is in UTC.

But the Seiko has been discontinued for years and is very hard to come by. When one is found second-hand the soft matte titanium case is often scratched or re-polished, losing the careful satin finish. They border on unicorns.

The rest of this article pivots on the idea that I decided to try something new — buy the parts of the Seiko wherever I could find them and learn to get it working.

NWS (Nonworking Sample) Watches

A very clean looking one was found on ebay finally: a “non-working sample” or “NWS”.

NWS’ are used by dealers to promote new watch models to the retailers. They don’t work — they may have the hands glued or taped in, or have a non-working movement inside to simply hold everything in place. When it arrived, at first glance everything looked like it should just start ticking, but…

Deceptively Timekeeping-y. But fused solid at the classic 10:10 position
MSRP in the early 2000’s Most watches sell for under MSRP

Case back off

Using a cheap JAXA tool (and a sandwich bag between it and the case back to reduce chance of scratching), the case back came off easily. The titanium is really soft, like aluminum. There was no waterproofing gaskets at all and the first indication was the lack of one around the case back threads.

The movement is a seiko 7T62 quartz chronograph — a glue-filled corpse of one in this case — defective ones are used in NWS watches just so they have something to stick the hands to.

Total organ transplant

Since the movement was dead, I ordered a replacement and a movement transplant was in order (aka total organ transplant). The mechanics of a watch are connected to, but independent of the watch face and the hands, so they all must be separated.

I read up on how to remove the crown and winding stem (well not really a winding stem since this is a battery powered movement). Once this was out, the movement pops out like a mecha-pancake and the watch dial and hands could be inspected.

The part I thought would be make-or-break was being able to remove the hands. As an amateur hobbyist, I was confident I would destroy some of them in all the prying. Even though hobbyist watch tool kits come with a hand puller tool, I chose to use the little levers based on videos from YouTube — they offered more control and smaller work area considering all the sub dials. Again, a sandwich bag between the tools and the watch acted as scratch protection. If the hands were cemented in place, I would find out in destructive pulling!

Okay let’s remove the hands. All seven of them…

Disturbingly easy. They were not glued and in fact I have no idea how they stay on beyond friction. I imagine removing hands is something you can only do a few times before the friction fit is wobbly.

New movement

A Hatori YM62 can be purchased for maybe $40 and is a 1–1 drop in replacement for the 7T62. It came in a bag from Esslinger with a battery and a long winding stem and the piezo alarm.

Although only $40, it is interesting to remember how amazing quartz chronographs were when Seiko made the first ones in the 1980s with the 7A28 series movements.

Before that, quartz chronographs were all digital, with 7-segment LCD or LED displays. Seiko decided they could have the best of both worlds with analogue hands and digital guts.

Back of the dial — it is just a brass plate with a few soldered pegs:

Getting the hands back on is tricky — it is finicky, but also, the hands have to be pointing in the same direction as the movement expects them to be pointing. Fortunately this movement has some hand angle fine-tuning functions buried deep in its ROM that can correct for guesswork.

The movement is alive and ticking once the battery is in, so everything can be tested outside of the case. The new movement has a date wheel that is black-on-white, and the original was the reverse. Not much to be done for that since the date wheel was glued to the movement.

Trimming the winding stem

This was the riskiest part for an amateur — the watch stem is supplied at some long length and has to be trimmed on the threaded end so the winding stem will engage its screw-down threads on the case (i.e. does not stick out half and inch!) because it is very strong, stiff steel, I ended up snapping it like dry spaghetti at the desired length between two side cutters then filing down the new end till the winder would screw on. The whole thing just slides into the movement and locks in place like magic.

Reassembly was a time not to rush things — at this point the hands had been iterated over for an hour or so. There was more alignment to do with the chapter ring (the donut of tick marks around the watch face)

With the new movement tested and then put back in. Things are looking up. New gaskets were later fitted to the winding stem, pushes, and case back.

Hey, it’s all done…and that was a few years ago now.

Since then I have learned more about watches, movements, maintenance, but this one is still a favourite because it was never supposed to work or run.

The watch recently died by ingesting water during a particularly patriotic outdoor ice carving event in a heatwave. A second copy was found, so now those donors are sharing parts and the repair journey is ongoing.

For a trained watchmaker this would be nothing to write home about, but this was the first time I’d even considered that something like this could be done, and it felt good to know that not everything is an unrepairable monolith of technology.

As an aside, the two worlds of mechanical and digital watches are crossing over in the art and science of MEMS — micro-electro-mechanical systems. This engineering method uses microchip fabrication techniques to make gears, motors, levers, and springs through etching of silicon, allowing incredibly intricate gear trains that take advantage of the springiness and low friction of crystal silicon. The Zenith Defy is an example of this where many components have been replaced by a single piece of silicon:

Some places to go from here

Seiko has a large ‘modding’ community and after market parts to customize their watches. They never gave up on mechanical watches and make many affordable models that can have almost everything changed with the tools shown here.

#seikomod insta

A step-by-step for customizing a Seiko mechanical watch

1940s-era educational video on how a mechanical watch works using a giant working model

The Watch Repair Channel is an exhaustively collection of repairs from a professional.

Note: My original article is here

Interactive developer for science and data outreach, github.com/jufa

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