Last modified: 2023-09-22 00:36:29
< 2023-09-20 2023-09-22 >The ETA calculation works really well, but the delta time is still much bigger than it should be. Seems maybe 100x to 1000x too big? Need to investigate.
I should try increasing the angle of the escape wheel teeth (laying them back further) so that they transfer impulse to the pallets more easily. Might make it run with less weight.
I had the idea that maybe the bottom of the case can be fixed to the outer barrel, so it will all rotate against your wrist when winding. Then the face essentially becomes the "frame" that the movement is locked to (via the winding ratchet). Or, to put it another way, there is a central frame, with the movement below and the face above. And we can potentially make it watertight by putting an O-ring on the join between the outer barrel and the frame.
Update: I think this won't be a good plan, because then the outer barrel is only held on by the inner barrel. The outer barrel can't be held on by the centre because the inner barrel needs a shaft to pass through the centre for the hand. It can't be held on by the outside because the outside needs to rotate for the winder.
So then the plan is that the caseback is held stationary, by attaching to the lugs. The face/frame is held stationary by attaching to the lugs. The outer barrel is constrained by the caseback and the frame, and is free to rotate in the cavity, with some ridges for bearing. And then we need one o-ring below and one o-ring above the outer barrel to seal it against water.
Are the plates also free to rotate in the cavity? What about the inner barrel? Feels like it might all be a bit sloppy. Need to 3d print a model.
OK, we could make a little round part with a bore that is a loose fit on the balance wheel shaft, and then cross-drill it to take the end of the hairspring, and then with the hairspring stuck through the cross hole, press it on to the shaft. The presence of the hairspring will make it a tight fit on the shaft.
Ideally the cross-drill would be centred on the tangent of the bore, rather than the centre line, but the centre line is OK if easier to make, will just need a bigger hole.
< 2023-09-20 2023-09-22 >