Knex Clock
https://www.youtube.com/watch?v=zvmOLhV_NYE
Brilliant design for the hand. Over comes the lack of correct gearing.
Differential: https://www.youtube.com/watch?v=rBfQeRWtpxQ
Sizing
The whole thing will be 7' tall.
I'm not sure I want to use corner connectors - I don't think I have enough. Instead, alternate yellows with corner bracing to hold the shape.
Hands
Rather than gears, we'll use rods for transmission. The minute hand will have essentially 2 teeth (two rods at 180°). That goes to a 3:1 reduction, which goes to an 8:1 reduction; for a total of 24. The 3:1 will be a little janky, but feasible.
Winding and Weights
I'd like to do all this with Knex chains rather than string - more authentic; but I'm afraid of how much friction that incurs.
For string, I think I'll use the mason line I have. Fishing line would hold it's shape, causing weird fluctuations in power.
The weights will drop down the center, I need to add a guide track.
The winding mechanism will of course go through a differential gear. Also need a ratchet for that to work.
Pendulum
As tall as the clock. The pendulum will actually rock in a cradle rather than spinning on a rod - lower friction.
A 6' swinging pendulum has a period of about 2.7s.
Torsion Tests
| Rod Length | String length | String Type | String Arrangement | Weights | period |
|---|---|---|---|---|---|
| 2 grey | 1 ft | mason | double | 1 wheel each | ?? |
Escapement
I've seen some good Arnfield escapements.
I'd really like to do an Anniversary (Torsion pendulum) escapement. It's Lego, but this is a good demo.
I may be able to combine an Arnfield with a torsion pendulum.