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There are semi-electric versions of mechanical watches based on "tuning fork" movements. They are cheap and accurate, and are a stepping stone between mechanica

There are semi-electric versions of mechanical watches based on "tuning fork" movements. They are cheap and accurate, and are a stepping stone between mechanical and quartz from the 60s/70s I don't have the skills or machinery to make a wristwatch sized version, but I did make a _big_ sized version: https://www.secretbatcave.co.uk/projects/electromechanical-clock/ https://www.secretbatcave.co.uk/projects/electromechanical-c...

aidenn0 3y ago
For a clock, could a worm drive provide the necessary reduction without the microscopic teeth? Tamiya sells small drives with a 150:1 reduction ratio.
- dexwiz 3y ago
  I imagine the increased surface area of the worm drive may cause more loss to friction than desirable.
- KaiserPro 3y ago
  Possibly, its less the reduction, more the "stroke" of the vibration (ie how far the tuning fork moves backwards and forwards.) I think for a large tuning fork, you _could_ use normal watch gears. However I don't have the skill to try that, yet.
  - aidenn0 3y ago
    That makes sense; the backlash needs to be much less than the tuning fork travel, right?
    - KaiserPro 3y ago
      Backlash isn't probably that much of a problem, the orignal movement has a locking "pall" that stops backlash: https://youtu.be/CPS7aNCAwAA?t=161 https://youtu.be/CPS7aNCAwAA?t=161 scaling it up you'd get something like this: https://www.youtube.com/watch?v=u48n-jvo5N0 https://www.youtube.com/watch?v=u48n-jvo5N0 to make it practical on a tuning fork, that movement of the forks would need to correspond to the tooth size of the wheel. For a large tuning fork, its probably in the order of mm, so not beyond home shop manufacture
      - aidenn0 3y ago
        A ratchet and pawl limits the backlash to the distance between the teeth on the ratchet gear; think of it this way; if it were to turn less than the radial distance between the teeth on the ratchet gear, backlash could still happen; similarly in regular operation, it turns the ratchet gear slightly more than that distance, and there is backlash until the pawl engages.

aidenn0 3y ago

For a clock, could a worm drive provide the necessary reduction without the microscopic teeth? Tamiya sells small drives with a 150:1 reduction ratio.

dexwiz 3y ago
I imagine the increased surface area of the worm drive may cause more loss to friction than desirable.
KaiserPro 3y ago
Possibly, its less the reduction, more the "stroke" of the vibration (ie how far the tuning fork moves backwards and forwards.) I think for a large tuning fork, you _could_ use normal watch gears. However I don't have the skill to try that, yet.
- aidenn0 3y ago
  That makes sense; the backlash needs to be much less than the tuning fork travel, right?
  - KaiserPro 3y ago
    Backlash isn't probably that much of a problem, the orignal movement has a locking "pall" that stops backlash: https://youtu.be/CPS7aNCAwAA?t=161 https://youtu.be/CPS7aNCAwAA?t=161 scaling it up you'd get something like this: https://www.youtube.com/watch?v=u48n-jvo5N0 https://www.youtube.com/watch?v=u48n-jvo5N0 to make it practical on a tuning fork, that movement of the forks would need to correspond to the tooth size of the wheel. For a large tuning fork, its probably in the order of mm, so not beyond home shop manufacture
    - aidenn0 3y ago
      A ratchet and pawl limits the backlash to the distance between the teeth on the ratchet gear; think of it this way; if it were to turn less than the radial distance between the teeth on the ratchet gear, backlash could still happen; similarly in regular operation, it turns the ratchet gear slightly more than that distance, and there is backlash until the pawl engages.