One problem with Copal motors is that they get noisy. The cause is often that dried lubrication and subsequent wear of the bushings causes too much play on the rotor axle.
Lubrication with light oil may help, but can also make it worse (at least that is my experience). I think what happens is that the oil dissolves whatever hardened lubrication is still there and thus the axle gets even more room to rattle around. Adding a thicker lubricant also does not work since this causes too much friction for the motor to start.
In my search for possible solutions I ran into these miniature ball bearings on AliExpress: https://www.aliexpress.com/item/1005...29771802I8kt7b
These are incredibly small and cheap. I had my doubts but nevertheless decided to give it a try.
First I removed the rotor and the bushings like shown in this video by Mackey.
Replacement was then quite simple:
The outside diameter (6mm) of the replacement bearings fits perfectly.
The inner diameter (2mm) was just a little too wide for the axle (1.5mm). I made this fit by wrapping a little tape around the axle.
At first the result looked promising. The motor runs very smoothly and starts immediately. It also appeared to run quiet. That is until I mounted the motor in the clock and put the clock on a table. The case and the table amplify any vibration that is still there. It is as if you can hear the balls rolling, like a constant faint white noise. It is not as loud and certainly not as annoying as the irregular ticking that the motor exhibited before, but also not as quiet as I hoped for. I left the clock running for a few weeks to see how it developed over time. There was no change. It is still running fine, but just a little too loud to my taste.
Conclusion: nice experiment, but not the quiet result I hoped for.
Next I will try some porous metal bearings (more or less like the original) that I also ordered at AliExpress.
I’ll keep you posted!
Lubrication with light oil may help, but can also make it worse (at least that is my experience). I think what happens is that the oil dissolves whatever hardened lubrication is still there and thus the axle gets even more room to rattle around. Adding a thicker lubricant also does not work since this causes too much friction for the motor to start.
In my search for possible solutions I ran into these miniature ball bearings on AliExpress: https://www.aliexpress.com/item/1005...29771802I8kt7b
These are incredibly small and cheap. I had my doubts but nevertheless decided to give it a try.
First I removed the rotor and the bushings like shown in this video by Mackey.
Replacement was then quite simple:
The outside diameter (6mm) of the replacement bearings fits perfectly.
The inner diameter (2mm) was just a little too wide for the axle (1.5mm). I made this fit by wrapping a little tape around the axle.
At first the result looked promising. The motor runs very smoothly and starts immediately. It also appeared to run quiet. That is until I mounted the motor in the clock and put the clock on a table. The case and the table amplify any vibration that is still there. It is as if you can hear the balls rolling, like a constant faint white noise. It is not as loud and certainly not as annoying as the irregular ticking that the motor exhibited before, but also not as quiet as I hoped for. I left the clock running for a few weeks to see how it developed over time. There was no change. It is still running fine, but just a little too loud to my taste.
Conclusion: nice experiment, but not the quiet result I hoped for.
Next I will try some porous metal bearings (more or less like the original) that I also ordered at AliExpress.
I’ll keep you posted!
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