Most quartz clock movements operate at 32768 HZ (32.738 KHZ) - and there are 86,400 seconds in a day. Easy to see, then, that even a good quartz movement, off by one part in 32,000, is off by two seconds per day. In fact most are good for 15-30 seconds per month (spm), which, while most of us take that for granted, is still pretty amazing. But not good enough for navigation.
For maybe forty years, until GPS positioning became common, the marine chronometer was either - or both - an electric clock or a high-accuracy battery-powered quartz clock modified to operate at 4.19 MHZ, more than 100xs faster, easily accurate to better than one minute/year. Such clocks, made by Seiko and European companies, were expensive. I think at the moment only the Chinese are producing such clocks, the Yantai Daxin CZ-05, and the Chijiu Clock Co. CJCD-2T, either for a little more than USD$200, maybe $300 delivered to the US.
But these days there are cheap oscillators at up to 25 MHZ and higher. A quartz clock operating at that rate would be truly a set-and-forget clock, accurate to a few seconds per year. And it would seem it should be neither too difficult to build one nor too expensive. And that there might even be kits! But if there are, I cannot find them.
The approach the chronometer makers appear to have used was to take a 32768 HZ common (not expensive) quartz clock movement and wire it to the faster oscillator, with other pieces to count and tell the movement when to "tick." The trick for someone like me is find out how to do that.
Cost should be not-much for an old clock, whether or not originally quartz, eBay maybe $25. A good Seiko or Takane movement, $20. The oscillator, $25-50. Other electrical parts, for a guess, $20. Total $100, give or take. For a clock that would need a battery once or twice per year, an occasional time check, and that would just plain tell the time.
Anyone interested in collaborating in making such a clock? For my part I would need simple and explicit direction on how to build/wire the electrics.
For maybe forty years, until GPS positioning became common, the marine chronometer was either - or both - an electric clock or a high-accuracy battery-powered quartz clock modified to operate at 4.19 MHZ, more than 100xs faster, easily accurate to better than one minute/year. Such clocks, made by Seiko and European companies, were expensive. I think at the moment only the Chinese are producing such clocks, the Yantai Daxin CZ-05, and the Chijiu Clock Co. CJCD-2T, either for a little more than USD$200, maybe $300 delivered to the US.
But these days there are cheap oscillators at up to 25 MHZ and higher. A quartz clock operating at that rate would be truly a set-and-forget clock, accurate to a few seconds per year. And it would seem it should be neither too difficult to build one nor too expensive. And that there might even be kits! But if there are, I cannot find them.
The approach the chronometer makers appear to have used was to take a 32768 HZ common (not expensive) quartz clock movement and wire it to the faster oscillator, with other pieces to count and tell the movement when to "tick." The trick for someone like me is find out how to do that.
Cost should be not-much for an old clock, whether or not originally quartz, eBay maybe $25. A good Seiko or Takane movement, $20. The oscillator, $25-50. Other electrical parts, for a guess, $20. Total $100, give or take. For a clock that would need a battery once or twice per year, an occasional time check, and that would just plain tell the time.
Anyone interested in collaborating in making such a clock? For my part I would need simple and explicit direction on how to build/wire the electrics.
So do I but it probably has a lot to do with being around aircraft engines a lot.
