ESA 9162 Tuning Fork Movements (Hummers)

[Adrian-VTA]

So I have two of these apart right now.

I don't recommend touching them unless you are extremely confident, have a microscope and a lot of patience, they are a real bugger to adjust. They are also incredibly fragile, you can break the index or pawl fingers with ease.

I won't go into great detail as these have been covered a million times.

The movement comes apart in two parts, an oscillator module with the tuning forks and the gear train. It's a pretty good design

Here's the oscillator module -



Train module -




Calendar Side -





And here's the pawl action in motion -

[camrok]

Wow. That is an amazing video. It’s surprising the amount of engineering that went in to producing something more accurate.

[philsinclair]

Hi. As Adrian has said, these things have a reputation of being tricky to work on. I have on good advice that first trap is the hands. Any very slight backwards movement of the hands will mangle the train. Most common failure is the coils. They are covered with a varnish which hardens and compresses with age causing a breakage off the fine wires. I have given up on the bloody things for the moment as coils are $150 each here and no guarantee.

[Adrian-VTA]

Best to avoid setting the hands backwards. That said, the problem is due to the design of the center wheel, which uses a clutch system to allow the hands to be set independently from the train. The lubricant dries, and the clutch gets firm, which means backwards setting of the hands will shred the index/pawl fingers.

I checked the wheel on this one and it was fairly free. I managed to get some lubricant in there and it was even better, so it should be OK.

Dec 19, 2017 14:07:06 GMT -8 philsinclair said:

Hi. As Adrian has said, these things have a reputation of being tricky to work on. I have on good advice that first trap is the hands. Any very slight backwards movement of the hands will mangle the train. Most common failure is the coils. They are covered with a varnish which hardens and compresses with age causing a breakage off the fine wires. I have given up on the bloody things for the moment as coils are $150 each here and no guarantee.