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Oh dear. What have we here?

Seiko 6218-8950

Grist to my mill is what. Something most sane folk might reasonably consign to the scrap heap but what I know, and what you should know by now, is that watches that look like this, more often than not, are ripe for revival. The chronic cosmetics are a signpost to the fact that this is a well used watch that has not been footled around with too much during its long life and therefore likely to contain some innards with potential.

This watch continues a recent Seikomatic theme here but this one is a bit of a minor aristocrat, fitted as it is with the 35 jewel 6218 movement, one clear level above the 26 jewel 6206 fitted to the Seikomatic featured a couple of posts back. Let’s not get ahead of ourselves though and instead take a closer look at what we’ve got.

The caseback reports that this is a Seikomatic 6218-8950 dating from July 1966, a model that came in two flavours; this one, with a gold-plated brass case and gold-highlighted dial and hands; and a more sober steel–cased version with the same model number but without the gilt-edged ostentation.  A view of the lower lugs provides no more basis for reappraisal than the initial view of the face

Seiko 6218

but does serve to highlight the very nice softly-domed crystal.   The crystal fitted to the steel-cased version of the same watch has sharp edges, which suggests that this one might be a non-standard replacement but I’ve seen a few examples of the gold-plated version with the same style crystal and so perhaps this was a distinguishing design choice in the original watches. What is clear at this point is that the case is a write-off, the underside showing considerable wear and none of the original sharp edges remaining (anywhere). However, I have a solution to that particular problem, as long as the insides look a little prettier than the exterior. Fortunately, that turns out to be the case:

Seiko 6218C

Given the massive wear to the exterior, the movement looks surprisingly fresh, with very little evidence of rotor wear to the edges of the bridges. A nice surprise is that this relatively late example is fitted with the third ‘C’ iteration of the 35 jewel 6218 movement, boasting a fine regulation adjuster on the balance cock in place of the teardrop adjuster we met during the 62MAS hot-rod project.

I had somehow expected an immaculate dial to lie beneath that crazed acrylic crystal but, although it was in decent condition overall, the markers and hands were quite badly tarnished, potentially letting the side down rather and undermining what I hoped to achieve.

Tarnished hour markers

Short of removing all of the markers and replating them, my only option appeared to be to polish the tarnishing away without removing too much of the gold plate. In the event, this proved very tricky. On some markers the tarnishing had penetrated through both the gold plate and the nickel plate beneath, whilst on others the tarnishing was relatively light, affecting only the surface of the gold plating. The end result is not quite what I had hoped, comprising a mix of semi-silvered markers showing remnants of gilt on exposed nickel plate beneath and others where I had had to work all the way through to the brass. Somehow though I am not unhappy with the result. We’ll see how it turned out towards the end of the post.

Extracting the movement requires the two case ring screws to be removed first, followed by the case ring and then the movement which, with the autowinder removed, provides a nice view of the fine adjuster on the balance cock.

Seiko 6218 balance

In some ways, although the fine adjuster provides a very nice degree of control over the regulation of the movement, it is geared directly to the regulator and so that control is somewhat coarser than provided by the teardrop regulation in the earlier editions of the movement.

Removing the dial and hands provides a view of the calendar side and an opportunity to compare this side of the movement with the closely related 6206A.

Calendar comparison

The differences appear rather minor: a slightly different design of day and date driving wheel and the presence of two additional jewels on the date dial guard and date jumper guard. Removing the two jeweled guard plates and the date dial reveals an additional seven jewels running around the recess in which the date dial runs.

Calendar jewels

With the extra two jewels in the guard plates, that brings the added value over the 6206 to +9 jewels, none of which play any significant role in the smooth running of the movement, other perhaps than in aiding a slicker passage for the date and day dials.

As we’ve seen quite a lot of 62xx movements recently, I won’t dwell on what was an uneventful dismantling and cleaning, other to take a quick peak at the usual encrusted barrel arbor hole in the main plate, happily exhibiting not too much wear.

6218 barrel hole

The return leg proceeded reasonably smoothly barring one heart-stopping hiccough when refitting the setting wheel plate:

6218 broken setting wheel screw

It doesn’t happen often, but sometimes screws just come apart without any provocation, a bear trap waiting to undo all of the effort expended in getting to the point at which they shear. If they break in the main plate then it can potentially be a show-stopper, particularly in a watch such as this one whose main plate is not interchangeable with the humble and far more common 6206. In this case, lady luck was smiling on me, the screw remnant still turning easily in the threaded hole and easy to work through, dropping out harmlessly on the other side. A replacement screw sourced from a scrap 6206A and we can move along, heart beat settled once more.

As the rebuild continues, it’s worth pausing to take a look at the stop seconds lever (hacking lever) fitted to this movement, and of the same construction as that in the 395 movement used in the 62MAS project:

6218 barrel and train wheels

You can see that it works by acting on the fourth wheel. In the later 6106, 6105B and 6306 calibres, the hacking lever works by coming into contact with the balance wheel directly. You can see the three positions of the lever in the photos below. In the first, the crown is pressed in; in the second pulled one click out to the quickset date position and in the third, pulled two clicks out to the time setting position. In this last, you can see the lever making contact with the fourth wheel:

6218 hack lever

In completing the calendar side, the only real potential fiddle is in the fitting of the date jumper and date jumper spring. In the date only variants of the 62xx series (such as the 6217 and 395), there is no outer lip to help keep the date ring in position under the gentle pressure of the date corrector spring. In my experience, the jumper and spring can only be persuaded to remain in place by simply willing it to do so through a process of horological transcendental meditation. Happily, with the day-date variants of the caliber, the date ring sits in a groove with lips either side and will generally stay put reasonably happily while you locate and fit the date jumper guard.

Date jumper 2

In the first photo above, we can see the date jumper positioned (and clearly itching to fling itself across the room) before fitting the guard plate whose dual role is to keep the date jumper in position as well as house the day jumper spring.

As we saw earlier, the calendar side is all but identical to that of the 6206A, but with a slightly different design to the day and date driving wheel. As we can see in the photo below, the location of the day and date fingers at 180 degrees to each other means that the date and day change over more or less in unison, rather than in the staggered fashion of later designs in the 61xx and 63xx series movements.

6218 day and date setting wheel

I quite like the design economy of having the date finger sit in a groove in the upper day driving wheel, thereby causing the latter to perform its function of driving the day disk.   You can perhaps see a little better how this all works by looking at the figure below taken from the 6218A service manual:

Day and date driving wheel

The manual reports that date driving mechanism works by transferring torque from the hour wheel to the intermediate date wheel to the day & date driving wheel to the date finger and on to the date dial. The day driving mechanism works by transferring torque from the day & date driving wheel to the day finger to the star sitting beneath the day dial disk.

With that all done, all that is left to do is fit the day dial and dial spacer:

Seiko 6218C calendar

ready to receive the dial and hands. I’ll save that particular reveal until the end though as I am still not quite sure to what extent the de-tarnishing of the markers has been an aesthetic success. Let’s turn now to the case.

At about the same time as I bought this particular flawed gem, I happened upon an auction for an unused, old stock 6218-8950 steel case and managed to bag it. Here it is:

Seikomatic 6218 case

As the case had been stored for the better part of 50 years, some of which evidently not in any protective wrapping, it is not entirely immaculate and the crystal in particular has that scuffed look acrylics can get which you know will not easily buff out. So, I removed the crystal, separating it from the dedicated tension ring which is designed to sit neatly around the outer edge of the dial. The tension ring I then fitted into a new 33 mm diameter crystal intended for the 6218-8971. This latter crystal has a softer, more rounded profile more in keeping with the crystal originally fitted to the now discarded gold plated case.

Crystal from 8971

In the event, the replacement crystal was a tad too broad of beam to fit into the aperture and I had to reduce its outer diameter a tad before pressing it snugly into place.

Seiko 6218 case and crystal

The case came without a crown and so I had to source a new one from Cousins and swap over the stem.

6218 stem and crown

We are ready now to fit the movement to the case. As the case ring is secured to the case using tabs, the movement goes in first, followed by the case ring, crown and stem and case ring tabs, secured using a pair of screws:

6218 recasing

The final step is to fit the autowinding mechanism and rotor, seal her up and finally take a look to see whether the new look works or not:

Seikomatic 6218-8950

I have to say, I rather think it does.

With a strap fitted we can take a look at the gorgeous dolphin case back, still showing some remnants of the green/blue case back sticker.

Seiko 6218-8950 caseback

A few more and we can wrap this one up.

Seikomatic 6218C

Seikomatic 6218 crystal

35 jewel Seikomatic

Seiko 6218 strap

Seikomatic 6218 wrist