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This is a tale of ups and downs, of resurrection and catastrophe. The subject is a high beat King Seiko fitted with arguably one of Seiko’s finest-ever mechanical movements. I bought it a little while ago, having probably paid just a tad too much given one small but significant minor cosmetic issue that I missed in examining the auction photos. See if you can spot the flaw:


This particular watch, a King Seiko 4502-7001, was produced in July 1973 towards the end of a wonderful period of creativity for Seiko that started in the early ‘60’s and which was driven forward by some very healthy inter-corporate competition between the Suwa division, whose factory was in Suwa, Nagano, and the Daini division, whose factory was in Kamedo in Tokyo. The former was responsible for the creation of the first manual wind and automatic Grand Seiko’s all of which used movements whose architecture was rooted in the same basic design dating from the late 1950’s. In parallel with that line, the Daini division developed the King Seiko sub-brand, latterly using freshly designed movements that incorporated modern technological features and whose performance had the potential to outstrip that of the Grand Seiko movements whose development followed a more traditional iterative process of refinement that relied on increasingly high jewel counts and careful production and regulation. Later Grand Seiko’s of this era would adopt Daini-developed movements in recognition, I think, that they moved the game on rather more convincingly. Of course, little did they suspect at that time the extent to which the whole industry would be rocked by the development of the quartz movement. High end Seiko mechanical watches would effectively wither and die by the mid-1970’s only to revive a quarter of a century later with the re-emergence of Grand Seiko in the late 1990’s.

The King Seiko 45 series watches are notable for the extraordinary beat rate at which they run: the HI-BEAT boast on the dial is no shallow marketing exercise (a charge that might reasonably be leveled at some of the highest jewel count 62-series models). The 45-series movements run at 36000 bph, almost twice as fast as the rather more leisurely 19800 bph of the automatic 6245 Grand Seiko movement described in the previous two posts here and here. One other notable feature of the dated 4502 fitted to my watch is that the date change is instantaneous, again contrasting with the slow but steady approach taken by the 6245. We discussed instantaneous date change in the context of the Rolex 1575 movement fitted to my 1603 DJ here and so it will be interesting to see Seiko’s approach to this feature.

So, let’s get on with the story then, starting as usual with a quick appraisal of the watch as received. In almost every respect, it is what I always hope for: an unmolested, unrestored, original watch in generally excellent condition but requiring some attention to revive to fully operational. In the latter respect, this example, whilst just about running, was doing so at a much-accelerated rate, suggesting something fishy in the balance hairspring department.

King Seiko 4502-7001The case shows some obvious signs of use but has sharp edges and looks really tidy overall.

King Seiko 4502 profileThe wear to the case back is light, barring a couple of minor case back opener slippage marks, and the gold KS medallion is present and correct and in excellent nick.

Seiko KS casebackThere is always a slight concern that corrosion might have affected the channel in which the bezel sits on watches with cases such as this and so before removing the movement, I popped out the bezel to take a quick peek.

Seiko KS bezel removedPlenty of grime and some minor surface corrosion but nothing to cause any concern and so off comes the case back and we can take a look at the 4502A movement.

Seiko 4502AIt is refreshing to be greeted by something that looks so unfamiliar, having recently spent so much time working on 62 series movements. The layout for a manual wind movement looks conventional enough with separate barrel and train wheel bridges but with a balance supported by its bridge on two sides. The train wheel layout, which we will get to shortly, looks somewhat unconventional to my eyes.

The movement is secured in place with the movement tabs, and so with these and the crown and stem removed, and the case spring set to one side, the movement drops out easily enough.

Seiko 4502 dialThe dial is in very good condition for the most part, barring some wear to its extreme edges and the two beauty spots close to the dial centre on a line to the 10 marker. The spots are perfectly circular flaws beneath the lacquer and are not addressable but they are a minor blemish and not something to cause great angst. The wear to the dial edge may look a bit ugly but fortunately is completely obscured in situ by the polished dial ring fixed to the crystal.  Hands off next:

King Seiko handspausing to note the historic damage to the edge of the hole centre of the hour hand, loosen the dial feet screws

Seiko KS dial feetand remove the dial, revealing the calendar apparatus with its intriguingly off-centre date wheel.

4502A calendarIt all looks neatly laid out and decidedly modern (by which I mean designed after 1965), the most conspicuous element of which being the instantaneous date change mechanism which can be observed once the date wheel and guards have been removed.

4502A calendar sideWe’ll see how that works later on when the movement comes back together. Before we move over to the train side, it is worth noting that this is a movement not exactly under-endowed with tiny springs waiting to zing their way across the room: three serving the calendar functions

4502A instantaneous dateand two serving the keyless works

4502A quicksetNow, let’s get to the bottom of the furiously fast-forward timekeeping. A superficial take on the train side will provide no clues

KS 4502Auntil the balance is removed and we see the source of the problem.

Hi-beat balanceTwo of the hairspring coils are adhered to one another, foreshortening the effective length of the spring and causing the movement to run very fast. Hopefully a good clean will release these later. The train side comes apart easily enough, first the crown wheel, ratchet wheel and click

4502A bridgesfollowed by the train and barrel bridges.

Seiko 4502A grear trainThe view above shows the complicated construction of the hacking lever, its three components connecting the groove in the clutch wheel all the way across to the other side of the movement, where the final dog-leg makes contact with the balance wheel to stop the movement when setting the time (below).

Hacking leverWith the train wheels out, the length of time since its last service becomes apparent with plenty of dried oil, grime and grot liberally sprinkled around the main plate and minute pinion bridge.

Seiko 4502A main plateRather than the conventional centre wheel arrangement of many of the other movements featured here, where the barrel-driven centre wheel drives the third wheel which drives the fourth/sweep seconds which drives the escape wheel, in the 45 series, the barrel drives a separate minute pinion

4502A minute pinionwhich then drives what Seiko call an off-centre large driving wheel and pinion via the intermediate wheel mounted beneath the barrel driven minute wheel bridge.

4502A minute pinion bridgeThe large driving wheel then transfers power to the third wheel which transfers it on to a fourth wheel located well off-centre. The fourth wheel connects to the escape wheel which, in addition to driving the balance via the pallet fork, also drives the centre seconds wheel.

Although the movement does not look obviously filthy, quite a lot of the surfaces are coated in a hardened film of old oil and the cleaning process requires extended ultrasonic time in addition to a double dose of cleaning machine agitation. With that underway, we can turn our attention to the case. The grottiest part of the case is within the bezel groove and some of the interior mating surface where the crystal sits.

Seiko KS mid caseMost of this is dirt or light surface corrosion and cleans off nicely with a toothpick but some is slightly deeper corrosion and I do my best to eliminate and smooth away as much as I can.

The crystal construction on this watch is a little different to that on most Seiko watches. The crystal itself is Hardlex tempered mineral glass bonded to a chromed metal ring that serves as the dial ring. The whole assembly sits on an L-shaped rubber gasket that then seats against the dial aperture in the case.

Seiko KS crystalThe arrangement is perfectly sensible but old stock availability of the crystal is limited to the extent that for some models featuring this type of crystal, replacement can prove almost impossible or requires that you spend amounts of money disproportionately large compared to the purchase price of the watch itself. It is always worth checking out spare parts availability for any watch before going ahead with its purchase.

The crystal gasket was in less than perfect condition, in part I suspect, because a replacement crystal had been clumsily fitted in the past, pinching the gasket and compromising its integrity. The corrosion to the gasket mating surface in the case is almost certainly due to water getting in through the pinched gasket. Here’s a photo of the old gasket compared with a new replacement:

Crystal gasketsand one of the new gasket fitted to the underside of a new crystal.

Seiko 4502-7001 crystalSupply of replacement crystals for this watch is thin and initially I was forced into buying a rather pricey but what turned out to be a cosmetically flawed crystal from an Ebay seller: the glue securing the crystal to the metal ring had become opaque spoiling the view from the top and I had to discard it (not literally but from consideration as a replacement). Fortunately, some months later Cousins came through and I’ve since bought two more from them, both of which perfect. Anyway, here’s the first of those two Cousins-supplied crystals in position

4502 crystalready to be secured into position by the bezel.

King Seiko caseTime to tackle the reassembly of the movement, starting with the minute pinion and intermediate wheel

Intermediate wheelsecured in place by their bridge.

Seiko bridgeNext we fit the cannon pinion, the keyless works and some of the motion works.

Seiko motion worksBack over to the other side for the barrel and going train

Seiko 4502A going trainbefore the fiddly business of reconstructing and fitting that three part hacking lever.

4502A hacking leverSeiko 4502A hacking leverWith the barrel bridge, train wheel bridge, crown and ratchet wheels plus click in place, we are all set for the balance.

King Seiko 4502AAs we recall, two of the balance spring coils had adhered together and following the cleaning process they remained stuck together. Careful manual intervention was thus required to part them, followed by another cycle in the ultrasonic bath. With this done, the balance spring assumes more of a symmetrical shape

4502A balance assemblyand we can hope that the watch might now run more or less to time.

Seiko 4502A 25 jewelsIndeed, at this point things look to be on track in the timing department but in attempting to perform a rough regulation I happened upon a significant snag: the filmy deposit which I had noticed before appeared to have afflicted the balance cock, stud holder and regulator arm with the result that the timing and beat error could not be adjusted independently. Moving the regulator arm also moved the stud holder, presumably because friction between the two levers, caused by the contamination, was leading one to impact upon the other. The only solution to this problem is to dismantle completely the balance assembly, clean everything thoroughly and try again. I’ve not performed this operation in the field so to speak and so this is breaking new ground for me but fortunately I have my staking set to help me out. Breaking the balance assembly into its constituent parts:

Balance disassemblyAfter cleaning, reassembly is simply the reverse process, but requiring a little additional work on the balance spring to make sure the outermost turn runs cleanly through the curb pins of the index lever throughout its range of adjustment.

Balance reassemblyNow, let’s get back to the calendar side, starting with that perplexingly complex-looking instant date changeover mechanism. We can hopefully get some idea about how it works as it comes back together. First the date cam, date cam jumper and the jumper spring into position:

Seiko date camThe date cam turns clockwise as the watch runs and so we can see that the cam jumper will make its way around the increasing radius of the outer diameter of the cam, moving to the left as it does so, until it reaches the cliff edge, down which it falls in a veritable jiffy, aided by the pressure of the jumper spring. But this achieves nothing without the other components: first up the date finger spring

Seiko date finger springsecured in position by the date cam jumper guard before fitting the date finger itself.

Seiko instantaneous dateAs the date cam turns clockwise, the inner edge of the finger rides along the eccentric surface of the inner raised lobe of the cam, thereby moving the tip of the finger inboard, away from the inner teeth of the date wheel.

Date fingerSimultaneously, the passage of the date cam jumper along the outer edge of the lower surface of the cam causes the axle to which the finger is secured to move to the north east (in the photo above) until the jumper slides down the cam cliff edge, instantaneously flicking the finger against one of the teeth on the date wheel thereby changing the date, the whole process regulated by the date jumper.

4502A date ringVery clever.  It looks like we are pretty much there barring the remaining calendar parts. The date wheel was quite tarnished and needed a good going over to get it looking its best

Date wheel cleaningbut the rest was routine and so on goes the dial and hands

Seiko dial and handsand we are ready to refit the movement to the case.

King Seiko 4502A new case back gasket, fit the case back, a suitable strap and we can survey the end result:

King Seiko Hi-beatYou may be wondering about the catastrophe mentioned at the start of the post. At this point in proceedings, I usually try to take a couple of semi-decent glamour shots to show the watch off to its best. This being December, the month of low grey cloud, and 6 hours of daylight in this part of the country, my default location in the house to get decent light is the top floor bathroom. Depending on conditions, I usually take my photos on a surface adjacent to the window, taking advantage of the generally indirect and soft lighting at this location.

Before the fallHowever, sometimes I open the window and use the outside window sill

Seiko KS Hi-Beatbut as you may notice, the paint on the sill is weathered and pock-marked and was reflecting in the polished sides of the watch so I thought I’d place a card beneath the watch to provide a cleaner surface. Unfortunately, having done so, an errant gust of wind gained purchase on the card and in a blink of an eye the watch was gone.

FallRise and fall indeed. Postmortem to follow.