2025-01-07

Last modified: 2025-01-07 15:55:48

Clock

I've added a bolt to space the fixed end of the string further away from the frame, so that the weight doesn't rest on the frame and stop the clock prematurely.

Will let the clock run, but I think the next step is to do so with the polyester string, and let the weight fall all the way to the floor. Then I need to work on making it run for longer with less weight before I add any more gearing stages

I've ordered some 6mm and 3mm stainless steel tube, 250mm long. I hope to use these with plastic bushings at the ends, running on a taut wire up the middle for a bearing, suspended by the spring.

I do kind of worry that there will be some up/down oscillation. Not sure what to do about that. Need to somehow make the spring very stiff up/down but still coil/uncoil nicely.

I'll try with the 6mm version first just to verify that it does in fact reduce the friction of the balance (it might not!). And regardless, I need to try a narrower balance shaft with smaller pallets and escape wheel teeth closer together.

Actually one thing I could do today is replace the micro bearings on the catching-arm shaft with some smaller diameter plain bearings, and turn down the ends of the shaft to suit. 2mm diameter on the bearing surface, 150mm long shaft.

Lol, just realised my shafts are 5mm not 6mm, ordered another stainless tube.

This is how it was running with the micro bearings:

My suspicion is actually that this won't help very much, and that the main source of loss in the arm-catching shaft is the pinion. It's also not obviously the case that a 2mm plain bearing does have less friction than a 5mm micro bearing!

Well it still winds with the new bearings, maybe it winds up a bit slower.

I reduced it to 11x M20 drive nuts, and it still winds, but quite slowly. Not sure whether it would wind with the micro bearings, I obviously put 12 nuts on for a reason, maybe this won't work reliably, maybe something else has improved, or maybe 2mm plain bearings is genuinely an improvement.