A recent example goes by the number 930072. The last two digits mean it was introduced in 1972 but without catalogs to reference there is no way to say how long it was produced.
I would say that it's a model of the Thinline series simply because it looks like other models in that line up. It's a tiny watch though, and although I'm 90% sure it's a men's model, you could easily convince me that it's a women's model.
The model comes in case with a 10K RGP bezel and stainless steel back. The shape of the watch is sometimes referred to a "TV-shaped". I think it has styling very similar to the 1968 Thinline 6504 and I'd probably name it a Thinline 651-something, since the highest Thinline number is 6514.
It's a small watch but my project watch came on a long Speidel expansion bracelet. It's definitely well worn based on the funk but it's not beat up at all.
The back is clearly marked Hamilton and has the model number stamped on the outside. There's a unique serial number on the inside of the case back.
The dial is in very good shape, a little dusty but not too bad.
The movement inside is a Hamilton 680, a 7.75 ligne movement based on an ETA 2512.
The inside of the case back is clearly a 1970's model - no Lancaster PA marked inside.
The movement is about the same size as my thumbnail. Tiny movements are basically the same as larger movements but the parts are much easier to lose.
While everything is being cleaned I will prep a new glass crystal for installation.
So far so good - all parts present and accounted for. Time for reassembly.
It took me about 45 minutes to reassemble the movement but that includes 20 minutes on my hands and knees looking for the click spring after if flicked off my bench and onto the floor.
Hmm... although the watch is ticking, it's not producing a clean signal on my timer. Notice the beat rate is 21600, also a good clue this is a 1970's model.
I recleaned the hairspring and finally got a clean signal on the timer. Now to try to reduce the beat error so it's a little closer to zero.
There... this performance is more than acceptable. The amplitude is over 200 degrees but it might come up further after I wind it fully.
I happened to have a vintage JB Champion lizard calf strap that seemed to pair nicely with the 1970's styling of the watch. This might make a nice Christmas present for a woman who appreciates fine vintage watches although I know plenty of men who don't mind wearing a small watch.