Seiko “Submariner” SKX031


The year is 1996. The US watches Will Smith welcome aliens to our planet at the box-office in Independence Day and the top track playing on the radio [that device we had pre-wifi streaming services] is Don’t Speak by No Doubt. This is very much a pre-#watchfam era in media. The just barely budded internet means little can be found online when Seiko announces a few new dive watches and a new (7002 successor) movement. It would make ripples for the next two and a half decades.

Via Watchlords forum

That year, the SKX line of watches and the 7s26 movement debuted. Within watch enthusiasts, one model in particular planted the seeds to create practically its own cult, the SKX007.

Over the last 25 years, the SKX007 and its 0020 case have become a benchmark within the #watchfam and among watch enthusiasts. Its dimensions, weight, wrist presence and specs are so well known by watch fans that an entire cottage modding community developed around it. The modding community transformed, literally, what this ISO rated dive watch could be; making it as customized to its wearer as one could want. Not to mention, upgrading aspects of it can act as maintenance.

Alongside the SKX007, many enthusiasts know the smaller ‘midsized’ scuba diver, the SK013, which gained a bit of a spotlight when Hodinkee’s Stephen Pulvirent wrote about its ‘Value Proposition’ back in 2018. The 013 (and its 0030 case) used a scaled down 007 (the 0020 case) case design, keeping the crown at 4:30 and the ISO certification. In recent years, it too has seen a surge of enthusiasm and mods.

Even though we think of the “SKX” as a crown-at-4 style watch family, in 1996 and onward, other case and dial designs began to comprise the SKX line. Some models are not nearly as known, perhaps due to a lack of marketing in the US. But, the SKX as a product line grew to have a bit of everything, from steel bezels to titanium cases. One variant in the SKX family grabbed my attention and, from what I can tell, was also announced alongside the 007 and the 013 in 1996; the SKX 031 and its 0040 case.

Outside a very few posts under #SKX031 and #seikosubmariner on Instagram and an article back from 2017 by Fratello, you’ll find there is only niche discussions around the SKX031 or its ‘midsized’ version the SKX023. At the time of this writing, there are just over 1000 tagged photos for the SKX031, compared to over 130,000 tags of #SKX007 alone. Keep in mind, Instagram was started in October of 2010; the SKX predates it by another 14 years!

The SKX031 uses a near 40mm 0040 case, a crown at 3 o’clock, and still uses Seiko’s more nature-inspired, organic, design language in the case curvature. Unlike the 007, the 031 breaks away from ISO certification, starting with a bi-directional bezel, dropping ‘Diver 200’ from its dial, and replacing it with 10-bar water resistance.

Looking at the bezel action, they also went back to using a spring and ball bearing in its case, instead of a circular bezel click spring as found on the SKX007. Yet, this lighter, smaller, 100m water resistant diver came with a screw-down crown. Now, the debate over water resistance and how much is “enough” water resistance, is a legendary argument in the #watchfam. For me, unless you are Captain Nemo or the adventuresome underwater archeologist named Tusker, none of us really need a watch, or anything really, rated for 100s of meters under the sea. Where the SKX007 was a tool for a recreational scuba diver with its ISO certification and 200m water resistance, the SKX031 (and it’s even smaller mate, the SKX023) could be seen as more akin to the skin-diver watches of the 60s and 70s; a style of watch that bridges the functionality of a dive watch without the overly built diving dimensions. What you get is a water resistant watch, with rugged specs to match, and the benefit of keeping time with a rotating bezel.

Unless you are Captain Nemo or the adventuresome underwater archeologist named Tusker, none of us really need a watch, or anything really, rated for 100s of meters under the sea.

What drew me in were the case dimensions and design on this diver. The 0040 case takes the standard “Submarier” style and adds more contour and smooth edging, which exemplifies the Seiko design language. For instance, the slight chamfer, where the top meets its side, rounds-off the case sides, as opposed to the more blocky ‘slab sided’ design of the vintage Tudors and Rolex. Even though this is a lighter spec’d dive watch, it still provides, as Fratello back in 2017 noted, an upgrade in design over the more popular SKX007. The dial was also an upgrade to this depth-downgraded diver. In Seiko’s archives, there is an upgraded dial variant of the SKX007, the SKX171, which includes applied markers, but this falls short of the 031’s dial. Seiko used applied markers, an applied Seiko logo, and an applied surround on the day/date window for the dial of the SKX031. This sub-style, 10-Bar watch stands out as more trimmed and detailed in design.

two seiko diver watches, one on an origional green ZA strap and the other on a grey ZA strap on the book On Puget Sound with a pocket knife
SKX007 (prototype ZA strap) next to SKX031 (production admiralty grey ZA strap)

Finding a Seiko 0040 Case

Fast forward to 2017. After spending a year finishing up the PNW001 watch project to commemorate the birth of my son, and finding out about the mod community around the SKX007 in the process, I started to hunt for a 0040 case for my own SKX031 build. But instead of finding a perfect condition example of this watch, I was on the hunt for another project watch. Tracking this case down became a more difficult task than I expected. At the time, many of the 0040 cases I found fell into the wide range category of ‘pretty rough.’ Now in 2022, I would say it’s even more difficult to find ‘original’ Seiko cases and dials for the SKX031. I’ve found that there are many third-party manufactures reproducing look-alike dials and cases (though not yet to the degree of the 007 or Turtle).

By 2018, I had a bit of luck. The well known and widely respected Seiko watch modder, now watchmaker, Nick Harris of Orion Watches freshly graduated from the watchmaking school in Seattle and was prepping for a mega cross-country move. I had followed Nick’s work online since his early modding days; his online writing greatly helped me get pointed in the right direction with project watch builds. From tips about Seikos, to helpful and encouraging direct messages when I was struggling with the Sellita SW200 and building the PNW001, Nick has been an inspiration to my modding. As luck had it, he had just the case, in just the right condition, that I was looking for (thank you again Nick). It was in rough shape, but workable rough shape.

Be sure to tune into Ep. 13 of the Analog Explorer Podcast | Collect ‘ing’ Around Watches to hear more on this story.

Updating the SKX031 to the 21st Century

After following many rabbit holes for how I might mod this, I got hooked on Seiko’s design history. My goal shifted away from modding it and into something new, to restoring it. But I wanted to give it an upgraded restoration. Keeping it closer to what Seiko originally imagined, but bringing it into the 21st century, I looked for upgraded parts. As often as I found these watches thrashed, it made me wonder: how must they have been used? And to that, how honestly tough a simple Seiko watch is.

Crystal, Movement, Crown

To start off, I swapped out the 7s26 for the contemporary NH36 (white label version of the Seiko 4r36).
Tip: keep the black spacer around the movement

Doing so required a new crown and stem, as the 7s26 crown and stem of many of the SKX’s are one assembly that cannot be separated. At the time, this lead me into a problem; the crown. Standard SKX007 and 013 crowns are too big. Having gotten to know others in the #watchfam community, I knew of a watch modder and blogger, Seiko Parts who had just updated a post on a project they were working on, creating a mid size diver crown replacement to fit the 0040 case. This new screw-down crown was also designed with a twin gasket system on the stem, as opposed the original single gasket from Seiko. New crown in hand, I also upgraded the crystal to a Crystaltimes Horology double dome sapphire crystal with new gaskets all around, which would maintain the original 10-bar water resistance (and perhaps increase it, although I’ve never tested this) .

Hands, Dial, Bezel

Sourcing a dial and hands was a bit tricky. After going through countless non-original third party replica Seiko dials, I found an original dial and handset out of Spain. Much like the case, it was well used, but able to be cleaned up. Knowing this dial is copied by third party manufacturers, it takes looking at the details of the dial to tell if it is authentically Seiko made. Usually, it will just ‘look off.’ But, another way to check is the printing at the 6 o’clock. I’ve found that replicas can’t print it small enough to match the original. If it looks too big, they aren’t original Seiko.

The minute and hour hands are the standard full size SKX handset, save for the seconds. The SKX031 and SKX028 use a white arrow seconds with a small lumed triangle end with an elongated tip. I sourced mine out of Europe from a shop that parts out scrap watches. The dial and hands were well aged. But, using Rodico putty on them cleaned them up for the most part.
Tip: do not use, or take care when using, Rodico on the applied Seiko logo. The letters can be easily bent or misaligned if you push too hard from the top or bottom (as I found out the hard way, having to carefully reshape the S).

Lastly, I swapped the stock aluminum bezel insert to a bright blue one, then later swapped it out again in favor of ceramic. This was done to better accommodate the domed crystal, as the ceramic insert has a slight slope to follow the dome of the crystal better. The ceramic blue insert color tone also better matched the slight blue AR coating on the crystal.

Custom Engraved Caseback

There was an era where the blank caseback of a watch was a blank canvas to commemorate something for its wearer. Having worked with Bellingham’s own Bay Engraving before on customizing the case back on the PNW001, I went back to them for this project as well. It shares the same engraving as the PNW001; my wife’s, son’s, and my name, a PNW compass rose, and the coordinates of our back yard. My hope is that, one day when my son has my watches, it will remind him of where he came from, and the PNW culture in which he was raised. As it is on the case backs of three watches that have been on countless hikes for Adventure School, it is an etched part of his PNW childhood.

The hashtag #alwaysreadthecaseback is a tag that is attributed to Hodinkee editor Cole Pennington, who shared the same sentiment for the importance of caseback engraving. His February 2020 Horological Society of New York presentation on Horological Homecoming: The Hidden History of WWII Watches is a great resource for looking at how a line of text engraved on a military watch can paint an entire image of the history of its wearer.

Why go through all this to rebuild an “only 100m” Seiko watch?

Because at the end of the day, I liked it and I wanted to. Is it ‘all original?’ No. Is it ‘franken’d?’ Sure. But to me, it is a rebuild that brought it back to life, with contemporary specs so that it can once again adventure. It has seen the tops of mountains and been in our lakes and rivers. Yes, the cliché is true that it rains often in the PNW; but, many of us Cascadians are avid outdoors folk, myself included, regardless of the forecast. The only water resistance an adventuresome dad needs, in between the northwest’s lakes and mountain that is, is enough to save something from going down the drain during you toddler’s bath-time, or prolonged submersion in drool. Sure, I do dive. And yes, I do wear a dive watch on one wrist and a dive computer on the other. But, just like a dive computer, an over-spec’d dive watch has a time and place for me. For the rest of the days in the week, I want something just as robust for the office as for the trailhead. And that is what I built into this watch.

Because at the end of the day, I liked it and I wanted to. Is it ‘all original?’ No. Is it ‘franken’d?’ Sure. But to me, it is a rebuild that brought it back to life, with contemporary spec so that it can once again adventure.

Some in the #watchfam get hung up on the specs of a watch. No differently than a geek getting caught up in the specs of the latest and greatest computer or technology. Really, do you need all the extra? Having a maxed out AV editing powerhouse MacBook doesn’t really help you if you live in Word-docs. Having a watch that can go deeper than this recreational diver is certified for, doesn’t make it ‘better’ [again, unless your name is Nemo or Tusker].

For me, what makes this “only-100m” dive watch better is the story of putting it together, where it came from, and where it has already gone; from being on my wrist when my, then 4 year old, son climbed his first small mountain, to accompanying me on my own mountain adventures across the Northwest. It’s tough enough to be clung onto by my toddler (with a ZA strap) when he slipped off a log while we were exploring a waterfall, but it’s also small enough that it even slipped under the cuff of a suit standing as best-man in my climbing partner’s wedding. Could the upgrades between the crystal and crown have helped with the depth rating? Perhaps. But at the time of this writing, I have not gotten my SKX031 retested and I’m not in a hurry to do so. I have other watches that accompany me under the waves and at depth. For the regular PNW life pressures that this undergoes on a daily basis, it holds its own just fine. It has survived our rivers, lakes, mountain tops, and a toddler’s bath-time. It also accompanied me taking my son out into the mountains, up until Covid (read about the year of pandemic patina and the Aquascaphe Bronze).

To him, it is just “dada’s adventure watch.” It is those memories with him, where we went, what we summited, which mean more to me than the specs of an “only 100m” watch.


On Daddy-Duty