In my wife's aunt's effects there is a Zodiac SST 36000 with day and date.  The face is a dark red tone with gold roman numerals.  It has a number (s/n I assume) on the top of the case - 2280322 and "GOLDELECTROPLATED G20 SAD" on the bottom of the case.  When I picked it up and handle it, it started running.

She was a retired Air Force nurse on active duty all over the world from 1956 to 1976 so I assume the vintage is in there somewhere.  Any information is appreciated.  Thanks

That was bought at the end of her career then. Looks to be in nice condition though so maybe it went into a drawer shortly thereafter. Looks to be the man's model.

You can look in the Gallery for other SSTs. It would make a nice family heirloom to pass on but be sure to read the Watch Repair section before anyone starts wearing it.

The "G20" means that it is electroplated with gold to a thickness of 20 microns. That's not quite as robust as "gold-filled", which is usually much thicker, but it's a lot better than modern electroplating or PVD, which is often 10 microns or less.

Butch is right about getting it serviced if you are going to use it. It's not that expensive with BWG (email Butch to find out more) and it will restore the watch to fully usable condition. This watch has value as a keepsake, but it would have even more if you could confidently wear it any time you wanted to.

The SST day-date movement was a Zodiac Cal. 86, which has a high-beat escapement (36,000 beats/hour), and is based on the A. Schild caliber 1687. Zodiac, Girard-Perregaux, Eberhard, Doxa, and Favre-Leuba went in together to create an autowinder for this series of movements, in the early 60's. Ebel also used that movement, and presumably others as well. The autowinder is what makes this watch run when you move it.

Here's a picture of a Zodiac cal. 86 (this one is date-only cal. 88, but that difference isn't visible in this picture), borrowed from Roland Ranfft's superb online database:

(https://www.vintagezodiacs.com/zforums/proxy.php?request=http%3A%2F%2Fwww.ranfft.de%2Fbidfun%2Fkatb%2F2uswk%2FZodiac_88D.jpg&hash=98568a320292a369ba7661608add0ac0c5be65dd)

The Cal. 86 is a very nice movement. The high-beat escapement means that the seconds hand moves very smoothly, and that was a feature that many companies were seeking to compete with quartz watches back in the day. Now, only Seiko and Zenith make 36000-bph movements, in both cases substantially up-market, and in both cases developed right around the same time as the Zodiac 86 and 88. Also, Zodiac ran an ad for this series of watches touting their accuracy--they were guaranteed from the factory to run within a minute a month (i.e. no more than 2 seconds per day average rate error). The movements used a Triovis micro-regulator to help achieve that performance. The movement also provides a hacking feature, which stops the seconds hand when the stem is pulled for setting. The day has to be changed the old-fashioned way (by advancing the hands with the stem pulled), but the date can be advanced one day by momentarily pushing the stem IN. This is a very nice feature that allows jumping over 31 in a short month without affecting the day-of-week setting.

Zodiac did not decorate their movements to the extent that more upmarket brands did in those days. But they are cleanly finished and well-featured, putting resources where needed to maximize performance. These were watches intended to be used, not garage queens. Because of that, they were affordably priced and very popular in military base exchanges, as your aunt's history bears out. This may have been a gift from her colleagues, or from someone she cared for as a nurse.

I love these classic 70's designs, but I have to be in the right mood to wear them.

Rick "wear it in good health" Denney

Nice post Rick! THE best I have seen in quite a while. Way to help out the new members!

Thank you Rick, I didn't realize there was THAT MUCH to know about a watch.  I have a new development and I don't know how serious it is.  As I said, the watch started running when I handled it (which I think is good)I  and I just put it down until I found out more about how it works.  When I read your post I tried to set the time - and the stem pulled out completely (which I think is bad).  I'm guessing that may be why it was in the jewelry box instead of being worn.  Does this make it cost more to repair than it is worth?  Not only am I new at Zodiac watches I am also new at communicating on a "forum".  How do I contact BWG repair service that you recommended?

Thanks again.

IdahoBoy

Not necessarily a problem, or expensive to repair. Stems are held in place with a little locking device that is actuated by a button or screw on the back of the movement, to facilitate easy stem removal. The stem has to be pulled before the movement can be extracted from the case.

All the more reason to send it for routine service. Email or PM Butch (the site owner) for his advice on a repair shop. That's how it works here. He'll connect you with a guy who specializes in Zodiacs. He'll give you an estimate before repairs so you'll know what your in for. You got the watch for free--the repair will be less than what it's worth in working condition, and more than what it's worth with a loose stem.

Just click the envelope symbol in the lower left of any of Butch's posts.

Rick "or, throw it away, but let me provide the trash can :laugh:" Denney