Accutron – a well tuned watch.

hought I'd post one of my more unusual watches. Not that unusual I suppose but different in that it doesn't have a hairspring or balance wheel – and it doesn't tick.
It hums………. and this one's been humming along since 1967.

Accutron 218D - the Tuning Fork watch.

The second sweep hand is a true sweep with no jerks at all as it just smoothly “sweeps” around the dial – other than that on the face of it, it looks a very traditional 60's 70's watch. Good size at 40mm diameter, 18mm strap or bracelet with removable spring pins to fit.
The back however isn't a “snap” fit as this model 218D is waterproof (according to the stainless steel back) and has a stainless screwed collar that secures a separate inner plate stainless steel back. Internally there is a rubber sealing ring to ensure a watertight seal.
And here any resemblance to the “normal” watch ends – as inside looks about as different as you can get!

218 Accutron movement

See what I mean?
And no the image is NOT out of focus – you will note that the two little coil assemblies look out of focus, but in fact these are fitted to the ends of the “tuning fork” which are vibrating at 360 cycles every second (360Hertz). In fact you are looking at the first ever “electronic” watch.
Bulova used to guarantee their Accutrons to about 1 minute per month (or 99.9977% accurate as their sales literature used to say) which was quite astonishing in those days. So much so that it was installed as the timing device in the Telstar Satellite and used to switched off it's beacon transmitter on July 16th 1964.
Becoming more scarce these days and nice to have one that runs. Could perhaps do with a bit of a clean but is in original condition, not restored at all, so I'm pretty pleased as it was not expensive when I picked it up on the net some time ago.
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