2023-12-07

Last modified: 2023-12-07 20:50:51

• Stepper motor clocks
• The watch

Stepper motor clocks

The 33uF capacitors have arrived from Digi-Key.

The plan today is:

• try to finish the dials
• test with a 33uF capacitor and compare the waveform from the DSO
• model the geartrain for 1:25 6:57 11:65

The dials went broadly OK. I'm not really pleased with them, but they'll do. I accidentally drilled the holes in one too close together, so may need to reprint the dial feet again. And the hand-drilled holes are pretty poor quality compared to the CNC ones, I should have used the CNC router to do it.

I've lacquered them and left the lacquer drying in the garage, but I expect they will need to come inside to dry properly.

I would say the trace with the 33uF capacitor is not drastically different from the 47uF one. In fact the phase shift looks almost identical. So probably the plan is to use the 9v and 12v transformers, and leave the 47uF capacitors in place?

So next up is modelling the new geartrain.

Let's try the mocked-up geartrain from the other day, but with the second-wheel tooth profile modified to make the teeth narrower and the gaps larger:

And then maybe there's half a chance of it meshing against the 6-tooth pinion of 50% larger module??

Failing that, I will probably have to arrange for them to have equal module, which I think will require the teeth to be cut into the 5mm shaft. In which case the plan is to glue some brass or aluminium over the shaft and then use the 4th axis to cut the teeth with a ball-end mill.

Actually I don't even think I need to use the 9v and 12v transformers. I think the only reason I thought I did is because the clocks were losing time, but I now know that to be caused by the incorrect gear ratio.

Though I may switch out to a higher voltage just to be safe. Actually I can't be bothered, I'll just leave them both running for a few days and check that everything seems well.

OK, great success, I think these gears are working. I have both clocks with the new geartrain, and hands and first wheel's synced, at 14:18. Beech clock has 12v transformer, bamboo clock has 6.3v.

20:21: the clocks still appear to be in sync both with each other and with the correct time. Good.

So as long as they continue to keep good time, I think I have finally finished both clocks.

The watch

What's the current status on the watch?

• the metal escapement prototype is bad, I will scrap this one and move on
• the 3d-printed 3x escapement works well, but with some questions about why the impulse pin rubs on the upper limit of the slot
• the 3d-printed 1x escapement almost ticks, probably needs pivots freeing up, maybe hairspring tweaking

So I think next jobs are:

• take pictures of the range of motion of the lever, compare to CAD using Gimp, work out why it is rubbing
• drill out the pivots slightly?
• try to make the 3d-printed 1x escapement run
• consider starting on a metal 1x escapement of the new design