In 1928, Girard-Perregaux was purchased by Otto Graef, a German watchmaker and owner of MIMO (Manufacture Internationale de Montres Or), the company that went on to produce one of the very first slide rule watches, the Mimo-Loga. This Girard-Perregaux is probably the one referred to as a variant of the Mimo-Loga by Alan Trott in his excellent history of the Breitling Chronomat. Edwin Datschefski scanned this photo from the book, Kahlert, Helmut / Mühe, Richard / Brunner, Gisbert L.: "Armbanduhren - 100 Jahre Entwicklungsgeschichte", published by Callwey München, 1996
Here's a page from the Chronosport 1968 catalog showing two slide rule watches, the one on top is a Selectron, and the bottom one is an Agon. Chronosport was "Europe's largest specialists in the field of sports and special watches, timers and timing equipment." They list Bath, London and Zurich for locations.
Page 3 of Chronosport's 1969 catalog has another Selectron slide rule watch.
The Cimier was produced in the late 60's. This one was posted on Edwin Datschefski's web site.
David Alstott kindly offered these pictures of the Gallet Excel-o-graph and some of it's variants. I'm not sure of the years when they were produced, but certainly the 60s and 70s.
This one is the Excelsior Park version
Robert from Germany sent in these photos of another Excelsior Park version.
Robert also sent me these wonderful pictures of his Elka. He writes "Elka is an Netherland distributor/Importer who sold the Excel-0-Graph as a own brand. It the same watch like the Sinn Navigator (The Sinn is a pre 903, name is just Navigator), Gallet by Racine or Excelsior Park."
Check out Robert's photo of the movement!
Robert also sent me this picture of the Eberjax. On first glance, I thought it might be another Gallet variation, but Robert set me straight. "Eberjax was a company, that used swiss movements (cal-suisse), build and sold their watches mainly in France, also to french military. The Landeron 248 movement indicates the Eberjax is build ca. 1965 to 1968."
Robert pointed out a very obscure slide rule watch from Orator. He writes:
"a rare bird, Swiss made / build in 1993 and sold by Artes, only 500 pieces, general look and case very similar to the
contemporary Breitling Old Navitimer I with Ref. 81610, also same movement Valjoux 7750. With a new price tag in 1993
of DM 2.800.-- (¤1.400.--) it did not really was a "poor mans Breitling Navitimer". Have a look for the special A in Orator,
looks like the sign on military flight chronographs." The first picture is a scan is from the original sales brochure.
The Mondia Memory is a very unusual watch. It has two moveable scales each with it's own winder. You align the two scales with a hairline on the crystal. The two separate winder stems are above and below the crown--all of which are visible in this picture of Dick Lyon's watch.
Fortis produced the "Easy-Math." This photo is from Edwin Datschefski's slide rule watch site.
The Fero Calculator was a large 52mm manual wind model with tachymetre from the 70s. (Photo courtesy 70s-watches.com)
Here's a great photo from an ebay auction of a Sheffield Computer Watch from the 60s. (Photo courtesy mollyfound)
The Camy Rally King is an automatic watch that was produced in the 70s. It's somewhat specialized as it only has one logarithmic scale which rotates around a fixed time scale. It would be useful only for making time-distance calculations (presumably of interest to rally divers) and not generalized multiplication and division problems. It that sense it can be thought of as "half a Navitimer" or flight computer. (Photo courtesy heuerboy.com)
I don't know the model number or year of this Certina automatic. It was orginally posted on Edwin Datschefski's web site.
Certina produced a limited run of 1000 Mick Doohan automatic models in the 90s.
Ikepod produces the unusual but very readable Megapode.
IMHO, Ventura produces the most cleanly styled slide rule watches since the Mimo-Loga. It's probably no coincidence since the Ventura chronograph model (shown at the very top of the first page) is called the v-matic Loga. Their other slide rule watch is even cleaner, since it lacks a chronograph. It's called the Ego Pi:
Sector introduced a new digital-analog model with slide rule sometime around late 2006 or 2007 called the Mountain Master. In addition to the slide rule it has an altimeter, barometer, chronograph, thermometer and alarm. It's one of very few slide rule watches to feature an altimeter. The only other one with an altimeter that I'm aware of is the long discontinued Citizen AeroChron from 1993.
It's a big watch with a 47mm case diameter, and 15mm thick. There are variations with metal bracelets, leather and rubber straps, but all of them come with an additional fabric strap.
Thanks to Dodo on the Poor Man's Watch Forum for posting pics of his watch and bringing this beauty to my attention.
I bought the rubber strap version and I'm impressed, but the watch is not without it's idiosyncrasies. While nowhere on the watch or strap is there any indication of the country of manufacture, it seems Swiss, as it preserves the Swiss reputation for doing things their own way. The functions of the four buttons on the side are different than you'd expect if the watch was made by Casio, Seiko or Citizen, and it took me a while with the poorly written manual (which is riddled with misspelled words) to figure things out. For example, the bottom right button is used to start and stop the stopwatch, unlike every other digital watch I've owned which uses the top right button. The date can only be displayed in the European format; day of month followed by month.
There's a handy and well thought out "key lock." Holding the bottom left button for 3 seconds disables all the buttons except if the alarm should go off. (How maddening if you couldn't turn off the alarm!) There is a screw down crown for the completely separate analog display. The digital display can be blanked out. There doesn't seem to be a way to turn off the beeps that accompany button presses. The Barometer has an alarm feature that can be used to warn of an approaching storm.
I can't speak to the accuracy of the altimeter yet, but the "reference mode" works just as it should, letting you recalibrate the altimeter when you reach a known elevation. I don't know what the "absolute altitude mode" is useful for. It doesn't allow the altimeter to be recalibrated, and changes in barometric pressure will throw the altimeter off. The backlight is excellent, but the luminescence is poor. The digital display is the most attractive I've seen, and it's highly legible. Slide rule accuracy is good with the tic marks lining up all around the dial. It's big and heavy, but not awkward. For some reason it's a fingerprint magnet, but hopefully it's just the residue of being recently manufactured. It's awfully good looking when it's shined up.
Zeno has three slide rule models in its current (2007) line. All of them are large "over-sized" watches. From left to right, the 775O in black, the 775O in silver and the 2220 in black.
Torgoen is a modern Swiss brand of quartz watches that feature slide rules. Some are styled like the Breitling Navitimer and some, such as the T7.05.02.S05 model in the center, are quite original.
Chase Durer is another modern Swiss brand that produces a variety of quartz flight computer models. Here are some from the 2001-2002 catalog.
Revue Thommen's model 17061.6537 has a Valjoux 7750 automatic movement.
In 2007, ESQ introduced a version of the quartz Beacon model with a slide rule.
Formex has the AS6500 series with a slide rule.
Also in 2007, Wenger introduced a very attractive quartz commando model
Page 2: Ollech & Wajs, Sinn, Hacher and Heuer slide rule watches
Page 3: Other Swiss slide rule watches
Page 4: Japanese slide rule watches--Seiko, Citizen, Casio, Orient and Kentex
Page 5: Other slide rule watches