I didn't tighten the chuck enough on the first attempt, so the ring came loose.
I did a second attempt on the same ring, which worked really well!
Some of the letters are duplicated because of the false start, and the text is distorted because the plastic is too flexible. I just need to remake the hook part in metal to make it stiffer and I think I'll be there. ... https://www.youtube.com/watch?v=wkiZHVjJCKY
I have no idea what I'm doing, but it looks like it's working.
For instructions: https://incoherency.co.uk/blog/stories/6040-cnc-grbl-arduino.html
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https://www.youtube.com/watch?v=L2JW4TT5e5E
This is a hand-soldered 8x8 LED matrix in a 3D printed housing, driven by an Arduino Uno and a MAX7219.
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https://www.youtube.com/watch?v=-HcQigWqp_4
There have been some slight improvements to the shape of the escape wheel and pallets, but the main improvement is that the balance wheel is now much bigger and the "front" pivot of the balance wheel is on a separate bracket so that the lever can pass over the top of the shaft, to allow for amplitudes over 180 degrees.
This is working pretty well now. Much higher amplitude, and much more energy in the balance wheel. The only thing that worries me is it takes quite a lot of weight to power it.
This example is at 3x watch scale.
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https://www.youtube.com/watch?v=NW2_8KEqEEE
This one has the pivots proportionally closer together, and a sharper angle on the escape wheel teeth, and the balance wheel balanced better, and a "proper" hairspring.
It actually seems less isochronous than the old one. I'm not yet sure if that's because the reduced scale makes errors more significant, because the pivots are worse, or because this design is more finnicky about tolerances.
In the old one the tick rate only changed by 7% as the drive torque changed by about 4x: https://www.youtube.com/watch?v=HvCGK8nU7pY
Whereas in this one the tick rate changes by 32% when the drive torque changes by 2x.
It seems as though the hairspring is underpowered for the moment of inertia of this balance wheel, so maybe it would work better with a stronger spring.
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https://www.youtube.com/watch?v=Jvf0xXi8Ryg