Wristwatch restoration, servicing and repair

Zodiac Astrographic SST (Zodiac Cal. 88D)…

I don’t mind the odd eBay gamble, but this Zodiac Astrographic SST was a real punt.

(Click pictures to enlarge)

The watch arrived complete but in decidedly average condition and showing no signs of life. It couldn’t be wound either via the crown or the automatic winding mechanism, and the crown and stem pulled straight out of the watch – not the best of starts.

Zodiac first introduced the Astrographic SST in 1969, and as this early advertisement shows they were initially available in two case styles, the square cased model in this post, and a round cased version – the smaller versions are of course ladies models.

Gold plated models were added a few years later, and so was the “Astrodigit”, a further development of the concept which displayed an additional ‘digital’ readout of the time in the centre of the dial.

As you may have noticed, the unique selling point of these watches is that the time is displayed as “floating” batons for the hours and minutes, and an orbiting red dot for the seconds… very 1970’s.

With the watch removed from the case you can see that the floating effect is created by using three transparent discs in place of regular hands, each one visible through the next. Inset you can see the individual discs and dial.

The movement inside is a Zodiac cal. 88D which was derived from the manually wound A. Schild cal. 1687/88 and was specially modified for the Astrographic watches as extra height was needed on the dial side to accommodate the discs. The cal. 88D is one of the high beat calibres found in all of Zodiac’s SST (Split Second Timing) models. It runs at 36,000 bph or 10 beats/second, which as well as other technical advantages, gives the red seconds dot a smooth sweeping action around the dial.

On disassembling the watch I found that two parts in the automatic winding mechanism were damaged, but I had a parts movement from a previous Zodiac SST project that provided all parts required, so the problems were quickly solved, and after a service the movement was up and running again.

Cosmetically the watch was in poor shape too. The case had seen its fair share of ‘action’, and as you can see in the picture below, the crystal was pretty badly scratched.

Replacing non-round crystals isn’t straight forward, but for this watch it is even more difficult as the minute track and Zodiac symbol are transfer printed onto the underside of the glass, meaning that a genuine Zodiac replacement crystal would be needed, but they are long discontinued.

I did eventually track down a genuine crystal in the US, but with shipping costs factored in, the overall price was more than I’d paid for the watch, so I thought I’d try to polish out the scratches instead – not a simple process for mineral glass.

Increasingly finer grades of emery/polishing paper are used to remove the scratches and the final finish is achieved with a damp felt mop charged with cerium oxide. That process generates a lot of heat, and I was afraid that the transfers would melt, so I completed the whole process by hand. Considering how much time the entire polishing process took, I wouldn’t recommend it unless you’ve got endless patience!

With the major marks removed from the case and after a re-brush, the watch was finally rebuilt. It still has its original Zodiac signed bracelet too which is a bonus.


5 Responses to “Zodiac Astrographic SST (Zodiac Cal. 88D)…”

  1. Adrian Baldwin Says:

    Hi Rich,
    A most interesting watch and a wonderful job you have made of bringing it back to life. Great to see another decidedly 70s piece resurrected! Even the name Zodiac is retro. Your patience with the crystal has certainly paid dividends. Will it make this one a keeper? Best regards Adrian

  2. Michael Harding Says:

    What a great looking watch and an awesome restoration. Congratulations!

  3. Dan Says:

    Great job Rich. I was once a happy owner of this model back when I was in the U.S. Navy on a ship in 1974 when I bought this watch for under 500.00. You made that watch look like mine which was brand new after purchasing it on a Navy ship store. Unfortunately after a couple of months it was stolen. I hear that only about 500 of these were ever made which makes this a limited edition. Who knows, maybe this watch was originally mine or 1 in 500 chance it was mine. I will always cherish it in my memories.

  4. Nathan Says:

    Absolutely beautiful work! It’s a good thing you got one with fairly clear discs. Some become extremely yellowed and cloudy and replacing them is extremely difficult.

  5. Marco J. Says:

    You did a wonderful job. Thank you for sharing these pictures. I still own the original 1973 round model which I was given as a present then. In the late 70ies it required a replacement crystal due to chips at the edge and also rebrushing of the steel case was done. Both repairs were performed by an authorized Zodiac store in Basel/Switzerland – and it cost a small fortune already at that time. Fortunately, Zodiac in Le Locle/Switzerland could still provide the original crystal. Good old times!