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In constructing a heart-over-head case to acquire another short-lived object of desire, absolute reality trumps virtual any day of the week. How else to appreciate the tactile charms that may be offered in the action, for example, of a ball bearing-assisted bezel, or the feeling of buttery precision transmitted through a crown when you set the time or wind in power?

The flawless exterior of a higher end watch at the start of its life serves to reinforce the qualities that extend below the surface and through to the inner workings of the watch. The question then is to what extent is the perception of the inherent qualities of a watch eroded if it is worn and used for its intended purpose? Watch collectors with large collections may buy an expensive watch only to wear it for a day or two every other month in circulation with dozens of others and as a result the watch acquires patina normally associated with daily use at a geological rate.

Back in the real world, an expensive watch purchased by a well-to-do Japanese executive, say in 1972, may have been worn daily and served its intended function faithfully until perhaps a decade or two later, overdue a service, its timekeeping becomes erratic or it stops altogether and it finds itself set to one side and perhaps forgotten. Such watches are my bread and butter. I have a particular and perhaps peculiar appreciation for shabby exteriors masking the charms or sophistication of a beautifully engineered interior. I’ve written before about the appeal of the basket case and in this current post I’d like to revisit that sentiment but this time, a higher-end dress watch fallen on hard times substituting for the battle weary tool watch.

Today’s subject is a Grand Seiko 6145-8050 dating from May 1972.

GS 6145

Its place in the Grand Seiko lexicon derives from two quarters: the first is its position within a model line featuring Grand Seiko’s first high beat automatic movement, the 6145A running at 36000 beats per hour; the second is that this particular model was produced just beyond the half way point in the lifetime of the Grand Seiko 61 series and as such found itself in a declining market for mechanical watches at a time of rapid ascendancy for the quartz movement. Consequently, this model might be regarded as some sort of marker of the beginning of the end of the first period of the high end mechanical Seiko wrist watch.

The introduction of the 6145/6 automatic movements to the GS line in 1968 marked the end of the rather short reign of the 62-series movement as the automatic Grand Seiko. Where the 6245 could trace its origins all the way back to the late 1950’s, the 61 series was a new design that provided the foundation in various guises of many mainstream Seiko’s made between 1968 and about 1979. In common with the 62 series, these movements came in flavours ranging from rudimentary 17 jewel manual wind 61A to the 6139 and 6138 automatic chronographs. The range also included the famous 6105 automatic fitted to the iconic 6105 divers, 6106 and 6119 day/date automatics fitted to numerous mainstream Seiko and Seiko5 models, the 6117 GMT fitted to the Navigator models and, in its most sophisticated form, the high beat 6145 and 6146 (latterly 6155 and 6156) automatic movements featuring quick-set calendars, hacking seconds and manual winding. And of course, I’ve somehow failed to mention the high beat 6159 fitted to that most ferociously appreciating Seiko watch from the 1960’s, the 6159-7001.

61 series patchwork

The 61GS is most obviously associated with the Grammar of Design 6145-8000 models whose case shape can be traced back to the classic Daini-produced manual wind 44GS.


Photocredit: Seiko

My 6145-8050 takes the lug surfacing of that watch one step further, forming a creased apex running straight down the 12 to 6 vertical.

61GS crease

(I told you it was a bit on the shabby side)

The watch sports a rather more audacious piece of design too in its faceted crystal.

61GS faceted crystal

In the past I’ve found this rather too much of an affectation to swallow but as my tastes have changed, I find the implementation in this watch rather likeable, a sign perhaps of the evolving 1970’s design flamboyance.

Before gaining entry, a survey of the case back illustrates the extent to which this watch has been used.

61GS case back

The formerly raised SEIKO and GS lettering as well as the Suwa symbol on the gold medallion have all worn away entirely, leaving ghosts of their existence.

I should probably mention at this juncture that the watch was not functioning at all when I received it. Not even a hint of a tick or of a tock. I often buy watches knowing they are likely to need some attention, indeed I rather prefer them that way, but usually there is at least some sign of life. In this case though, not a dicky bird. An attempt to wind in a bit of power via the crown did not bode well, with no resistance offered up, suggesting perhaps an issue with the mainspring. The reason my heart sank somewhat, and one of the reasons this post has been so long in the making, is that replacement of a broken mainspring in these movements is easier said than done.   We’ll get to the whys and wherefores shortly. Better get it open then, hadn’t we?

Seiko 6145A

Well, that is a sight for sore eyes, pretty much exactly what I would hope for based on the exterior condition, not withstanding the fact that it appears to be completely inoperative. You can appreciate I hope some of the attention that has paid to the movement in terms of its finishing, most conspicuously so in the radial graining on the winding weight. I like too the fact that the plates are all chamfered rather than straight edged and that the engraved text on the automatic winding mechanism is filled with gold paint.

Grans Seiko 6145A

Knowing that the fate of this particular watch hinged on the suspected condition of the mainspring, it was with a touch of haste that I dove in to investigate, my normal habit being to ferret away new acquisitions in the storage facility, much akin to a squirrel secreting away its latest acorn* to unearth at some future date. The autowinding mechanism on this watch is much the same in design as those fitted to the other 61 series automatics but you will see in this case that the winding weight is secured rather more elegantly with a pair of small screws and a single locating post (see above). Additionally, the pawl lever pivot jewel is covered (below left), presumably to protect the movement from migration of lubrication but maybe also to protect the pivot lubrication from contamination.

6145 autowinder

Removal of the autowinding mechanism provides access to the movement proper and an opportunity to note the additional features compared with the lower grade versions of this movement.

6145 main plate

Those of you familiar with the architecture of a 6105 will notice three significant differences, other than the expected presence of jeweled bearings serving the third and fourth wheel arbors and a Diafix serving the escape wheel: the first is the presence of a jeweled barrel arbor bearing; the second a crown wheel, there to provide the manual winding facility; and the third, and probably most conspicuous, the much smaller balance wheel, its smaller moment of inertia allowing the watch to run at a rate approaching twice that of the 17 jewel 6105. You will also notice the intriguing presence of the word ‘DO’ on the upper surface of the barrel itself. Its presence is not an entreaty to do something, as we might infer at this point, but to not do something. The ‘not’ in question is revealed when we remove the main plate:

Do not open

‘Do not open’. Why should we not open? Well, the reason is that the demands required of a mainspring in powering a watch running at 36000 bph are considerably greater than those required to power a similar movement at 21600 bph. The mainspring has to be thicker, to provide greater torque to the train. The standard 6105/6 mainspring simply does not have the wherewithal to generate the required amplitude when running at these much higher rates. However, a 6105/6 or 6139 barrel and arbor will fit this movement and I suspect that the reason Seiko decided to effectively seal the barrel and encapsulate the mainspring forever was to limit the potential for substitution of inferior mainsprings at service. This might appear quite a reasonable thing to have done at the time but from the perspective of 2016, with stocks of replacement 6145 barrels long since exhausted, and the mainspring never available as a separate part, a failed mainspring in these watches has the potential to be a show stopper.

61 series barrels

Before removing the movement from the case, I wanted to confirm that a standard 61 series barrel (taken originally from a 6139B) could form the basis of a substitute. With that barrel and standard mainspring fitted, the movement sprang into life but in its pre-service state, the amplitude was pitiful on a full wind, which strongly suggested that the standard 6139 mainspring was not up to the job. Before pressing on then, let’s disobey Seiko’s instructions and open up that crimped-down barrel lid to confirm what seemed like a certainty that the original mainspring was broken:

Broken mainspring

No doubt about that then. We’ll revisit the mainspring issue later but for the moment, let’s get the movement out of the case and get an idea of the state of the rest of the watch. First stop is the dial, for me the most important element of the whole watch in terms of its presentability.

GS dial

Other than a few very faint age spots, the dial is a beaut, the raised hour markers largely unblemished and little sign of wear to the edge. The hands are grubby but otherwise largely undamaged and so I have high hopes that this watch will scrub up nicely. I’ve set the time to 7.38 by the way to align all three hands to aid removal in the absence of any other way to tease the seconds hand into pointing at the twelve marker.

The mid case is the most aesthetically challenged element of the whole watch. On the up-side, it is unpolished and the edges as sharp as you could hope, but the case shows lots of wear, particularly around the lugs and there are some unsightly horizontal scratches across the upper flat surfaces, spoiling one of the key attractions of the case.

61GS case

However, a thorough clean, some fresh gaskets and a new crystal should smarten the case up sufficiently to do at least some justice to the dial and handset. I am also going to confess to the cardinal sin of attempting to work the scratches out of the upper flat surfaces. I reckon I’ve been partially successful, eliminating the scratches but eroding some of the flat. Ideally, I need someone who is a dab hand with a lapping machine to do the job properly but the only outfit I know in this country so-equipped prefers not to tackle this case and another lead in Europe fizzled. So I am left with what I’ve got, which given the sentiment within which this post has been framed, I reckon is ok.

Notwithstanding my struggles with the mainspring, the servicing of the movement proceeded smoothly, barring a bit of a wobble from the balance wheel and a precautionary replacement of both Diashock frames and cap jewels with new items. I don’t see much mileage in documenting the process in great detail other than to pause at pertinent points, because we’ve met the essential architecture on several occasions before. However, it is worth referencing the calendar side against that of a 6105A, to highlight the common base movement design and to note where some of the additional jeweling lies.

6105 vs 6145

Seiko 6105A (left) compared to 6145A (right)

On the calendar side of the main plate, we can see that the pallet arbor has an unusual capped jewel bearing whilst the escape wheel is served by a Diafix setting (below left). In addition, we can see the lower jeweled barrel arbor bearing (below centre) as well as a jewel serving the minute wheel (below right). Gratifyingly, there appear to be no redundant jewels at all and the declared jewel count of 25 is refreshingly free from the influence of those in the marketing department. Every one of them serves a purpose.

6145 jewels

With the movement completely dismantled, I go ahead with a thorough clean and dry of all parts before reassembling the setting works as a prelude to figuring out what to do with the mainspring.

6145 setting parts

When I realized that the mainspring was broken, I genuinely thought this one might defeat me.   Supply of replacement barrels dried up years ago; I have never seen one for sale and did not think that holding out for such an eventuality was the way to go.   I was also pretty sure that to substitute the barrel and mainspring from the 6139B would get the watch running but in all likelihood with unsatisfactory amplitude and that would completely defeat the objective of the exercise. Part of the point of a watch such as this is to know that its engine is back in full fettle, not limping along half-heartedly. And so I settled upon a plan to use the barrel and arbor from the 6139 and substitute the mainspring with a thicker and shorter Generale Ressorts spring. Here’s the substitute barrel and the new mainspring and if you look carefully, you may be able to see how comparatively beefy the spring appears:

6145 replacement mainspring and barrel

With the barrel lubricated, the spring pops in easily and appears to be an excellent fit all round.

New mainspring

With that done, all that is required is to reassemble the movement with the new barrel in place and hope for the best.

6145 reassembly

The proof of the pudding will be in the eating, but we’ll get to that at the denouement. With the calendar side complete, quickset and date changeover operation checked, on goes the dial holding ring

Dial holding ring

ready for the dial.

6145 dial

Back to the case, some elbow grease and a fresh facetted crystal (310V16GCS),

Cleaned 61§45 case

sets the scene for reunification of movement with case.

Seiko 6145A serviced

With the watch running, it is time to assess to what extent that substitute mainspring is playing its role appropriately.


This is the result of a somewhat lazy attempt at regulation and yet I am not sure I’ve seen as good a set of timing curves from any movement I’ve worked on, particularly in terms of the overall consistency in rate at different positions and the excellent amplitudes. The peak amplitude measured was close to 275 degrees with the lift angle set correctly on the timing machine, a figure rather more than satisfactory given my initial feelings about where this project may have been heading.

With the movement evidently fit as a flea, it is time to fit the autowinding mechanism and take a quick look dial side and the finished watch.

6145 finished

Seiko 6145-8050

Not half bad. The last remaining job is to identify a suitable strap. The watch will originally have come on a wonderful bracelet, complete with appropriately profiled end pieces.

GS bracelet

Photocredit: Yahoo Japan

Unfortunately, while it seems possible still to find these, they fetch very strong money in freely contested auctions, making them much too rich for my blood. Luckily, I am not really a bracelet man in any case but in electing for a leather strap, I have to contend with the rather slight dimensions of the partially hooded lugs. All of my existing 18mm straps are too thick and risk scuffing against the profiled V, which extends all the way down to the bottom of the case. After a bit of trial and error I happen upon a good value genuine crocodile strap free from stitching and just about skinny enough to squeeze between the lugs.

6145 on a croc

It is frequently the case that the conclusion of a project results in a watch that becomes my favourite, but this one I like particularly, not just because of how it looks, wears and performs but also because of the major headaches it created along the way. Shabby chic maybe, but now I think rather more chic than shabby.

High beat GS

Grand Seiko 6145

*I am hoping you will forgive the mixing of metaphors.