Hamilton's line of Thin-o-matic models is an interesting model line. Thin was in, in the 1960s and Hamilton produced watches with several different calibers of movements.
Most of the time the movement is a microrotor design produced by Buren. In fact, Hamilton eventually purchased Buren and after production in Lancaster ceased in1969, Hamilton moved production to the Buren facility in Berne, Switzerland.
However, not all Thin-o-matics used Buren movements. Some were made by ETA - the same company that made the Accumatic models. In fact, all Hamilton models produced nowadays are based on ETA calibers - they're all part of the Swatch Group today.
I'm not sure how many Thin-o-matic models used ETA movements - that would be an interesting topic to explore. I'd wager no more than 10%, perhaps less. One of them is the 1964 T-412. It was produced for three years.
The catalogs don't say so but it appears that the T412 was available with a metal mesh bracelet. I've never seen on but the catalog shows some interesting details.
My project watch arrived sans bracelet. It's fairly dirty but not really beat up so I think it should clean up nicely.
The case back has a classic pie-pan shape which indicates it has an ETA movement inside. The single-piece case opens through the crystal and has a two-piece stem.
The movement inside is a Hamilton 623 with 17 jewels. It has a strong family resemblance to other ETA movements of the day, like the 689 but it also looks a lot like ETA movements produced today.
With all the parts stripped from the main plate, you can see that the 623 is based on a caliber 73. That's the Hamilton equivalent of an ETA 2520, in case you ever needed to find parts.
The crystal has some deep scratches so I'll replace it. That will make a significant improvement.
A GS PHD (high dome) crystal in 28.3mm will do nicely.
All the parts, including the case, are cleaned and ready to be put back together.
The inside of the case back doesn't show any prior service marks. I wonder if this watch has ever been serviced in the last 60 years? The two numbers inside mean different things. The R number is unique to this case and is relevant only to the case maker, Star Watch Case Co. Presumably theres and -70 and a -72 out there somewhere but it all depends on how big the batch of cases for this model was. Perhaps this was the last case in the run? The other number is Hamilton's model number. This number will be in all T-412 cases. The last two digits represent the year the model was introduced - 1964.
The most difficult part of reassembling the movement is to get the four pivots of the train wheels to line uo so the train bridge falls in place. No force is needed - when everything is aligned properly it wil goes together. If it doesn't go together, then you have to fiddle with which ever wheel is out of alignment. It can take some time and a LOT of patience.
The rest of the movements goes together very smoothly and once the mainspring is wound up a little the watch takes off ticking.
Nothing wrong with this timekeeping. The amplitude is a little low but I haven't wound the movement up much.
The remainder of the automatic framework goes on next and the movement is ready for the dial and hands.
The finished watch looks fantastic, don't you think? I would describe this case as "cushion-shaped". Is it futuristic? Maybe, if you consider the funky numerals and dial design. However, Hamilton's first mens wrist watch was also cushion shaped - so it's a nice nod to Hamilton's watchmaking heritage.
No comments:
Post a Comment