The end of the 1960's closed the chapter on US Hamilton production and started a new chapter of solely Swiss-produced movements. The 1970's featured a new variety of interesting-looking models with newly introduced movements, including a second generation of micro rotor movements with and without date complications.
The first generation of Buren-made micro rotors were pink in color. The new generation were silver in color. Personally, I really don't care for the second generation design, and I'll tell you why below.
One of the 1970's models that I think is very unique-looking is the Dateline TM-5903. It looks like it could almost be computerized. It has a separate window just for the date below the main crystal opening.
The 1971 catalog showed it with a metal woven bracelet.
The TM in Dateline TM-5903 stands for Thin-o-matic. The case is stainless steel. The dial is grey and features long applied bars but I don't know if I'd call them hour markers.
Although this watch in engraved with a date from 1971, I'm calling this a 1969 model because the model id number ends with 69.
The case on the watch is polished brightly on the sides and brushed across the face. This particular example shows a lot of scratches from previous use and I'll try to remove them while the movement is in the cleaner.
The case is a two-piece design and the movement and dial are held in the back.
The movement inside is a 17 jewel 630 movement and you can tell it looks a lot like the earlier micro rotors but it's actually quite different. The second generation movements have an offset center wheel with an integrated cannon pinion. The center wheel is the wheel to the left of center below that is held in place with a metal bushing. The cannon pinion on these grades are notorious for becoming loose so the watch appears to run slow, even though the movement actually keeps good time. Replacement parts are no longer available for these grades so if you buy a model that "runs slow" be prepared for a costly repair bill.
This movement is missing a dial foot screw. I'll need to look for a replacement.
Under the dial is a cover that shields the components for the date complication. It even has printing to show you how to reassemble it.
The date complication is surprisingly simple, as the hour wheel (not shown) turns clockwise it eventually turns the golden wheel to advance the date wheel. The arm near the number four is an index to center the date wheel in position once it advances.
Once the set bridge is removed, you can see the cannon pinion to the right of the center. It's the left-most wheel in the series of three setting wheels.
The first thing to come off the back of the movement is the large ratchet wheel.
Well, here's a surprise. The click spring is missing and a piece of wire has been epoxied in place. The click spring keeps the click against the ratchet wheel and keeps the watch from unwinding. Looks like I'll need to replace the click spring too.
While everything is in the ultrasonic I will turn my attention to the bezel. First I'll pass the front over 400 grit sand paper. I'll use a flat surface to keep the brushed finish on the bezel running straight from side to side.
Next, I'll cover the brushed surface with tape while I polish the sides to a bright mirror finish.
Stainless steel is easy to polish but it gets pretty hot while doing so.
All the parts are cleaned, dried, and ready to be reassembled. Did I mention how much I hate working on these movements? There are a ton of parts and many of them are super tiny and easy to lose.
The epoxied wire is gone so I'll need to install a new click spring.
The same donor that provided the dial foot screw also provided a new click spring. Now I lust need to make sure I don't accidentally lose it. Springs have a remarkable ability to disappear into thin air.
Finally! It seems to take forever to put one of these movements back together but it's running with a good motion.
Not too shabby. I'll leave it like this.
Once the dial is back on I set the time forward until the date changes. Then it's midnight and I can install the hands.
Turns out this is a very difficult watch to tell the time on. The hands are small and the dial is grey so it's hard to see them and even harder to photograph them. Notice that the bezel looks remarkably better now, all the scratches are gone.
Well, I have to say this watch turned out great but I don't think I'm going to pursue any more of these 1970's Thin-o-matics. They really are a pain and it's luck of the draw if they will work properly. I'll have to cross my fingers and hope the hands move as they should. If they don't then I'll have to take it apart again and try to tighten the cannon pinion.
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