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

Arm Length	String length	String Type	String Spacing	Weights	period
1 red	18"	mason	1 connector	1 wheel each	16s
1 red	18"	mason	2 connectors	1 wheel each	8s
2 red	18"	mason	1 connectors	1 wheel each	32s
2 red	18"	mason	1 connectors	2 wheel each	39

I had to do a little testing and adjustment to get this to work. I didn't even try single stranded, double through one connector was to finnicky to be practical. Double spaced with one connector seemed pretty solid. At 2 connector spacing, the loss seemed pretty high, I'm not sure if that could be maintained.

The 2-red, single spaced worked really well.

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.

• https://www.youtube.com/watch?v=Wmk2mA6dg3o

I may be able to combine an Arnfield with a torsion pendulum.