Atmos Help Please

[Jonas]

Atmos help please:
A bit more than 6 months ago, I repaired and serviced an Atmos that had been in pretty rough shape. I got everything cleaned, serviced and adjusted according to the Atmos repair notes and the DVD instructions by Gerald Jaeger. It immediately started running like it should and kept perfect time.
Now, 6 months or more later, it slowed down over a few days and came to a stop. With time-lapse video, I was able to see that the problem seemed to be that it wasn't winding as it should.
I removed the bellows, checked that they were functional, checked the winding mechanism, swapped out for other known working bellows, adjusted the length of the winding chain, let the spring down, and checked if it would wind from a completely let-down state … nothing!
Every component seems to work as it should, but the assembled system doesn't seem to want to work.
Any help would be greatly appreciated!

Jonas

 

[Jonas]

I just remembered that there is a separate message board for Atmos and 400 day clocks. Would an admin be able to please move my post to that board?

 

[Schatznut]

Jonas, did your servicing include cleaning and lubricating the mainspring, and disassembling and cleaning the movement?

 

[Jonas]

Jonas, did your servicing include cleaning and lubricating the mainspring, and disassembling and cleaning the movement?

Yes sir.
Full disassembly, thorough cleaning of the spring, and all pivots, pivot holes and jewels; lubrication of the mainspring and first two (non-jeweled) arbor pivots with Moebius D3, and reassembled making recommended adjustments.

 

[Schatznut]

Maybe I missed it in the description of the work you've done, but does the mainspring charge if you exercise the winding mechanism by hand instead of relying on the bellows to do it?

 

[Steven Thornberry]

I just remembered that there is a separate message board for Atmos and 400 day clocks. Would an admin be able to please move my post to that board?

Moved.

 

[Dick Feldman]

Jonas,
Much of the following is anecdotal.
Since the clock depends on both temperature and barometric pressure, one of those factors missing or partially missing can/could affect the winding process. You do not specify your location but it seems to me that Atmos clocks have trouble winding at higher altitudes. That, in turn tends to indicate that they have an altitude limit. I have heard of Atmos clocks operating properly in Denver (5280+/- ft altitude) but not in, say Evergreen with is 7,165 feet. I have found that bellows measurement is not always a good indication of bellows health but that may have to do with altitude here. I could not speculate the operation in New Orleans.
You mentioned that you tried a known good bellows in the clock. What basis did you use to determine the second assembly was good?
Six months run time is an indication that everything is working except the winding mechanism. Atmos clocks will sometimes run up to six months after the winding mechanism has failed or if the winding mechanism is inoperable and someone has manually wound the clock.
In what condition was the winding mechanism when you first saw the clock? Did you find it partially wound? Did you find it completely unwound?
Many of the things we do to clocks make the clock repair person or the owner feel better but do not do much for the operation of the clock. Sometimes those measures introduce factors that may stop the operation of a clock. I know that a dose of WD-40 to an Atmos clock will cause it to fail in short order, regardless of condition or altitude.
Best of luck with the clock,
Dick

 

[Jonas]

Maybe I missed it in the description of the work you've done, but does the mainspring charge if you exercise the winding mechanism by hand instead of relying on the bellows to do it?

Yes, it does.
It will wind effortlessly if I press and release the coil spring manually.

 

[Jonas]

Jonas,
Much of the following is anecdotal.
Since the clock depends on both temperature and barometric pressure, one of those factors missing or partially missing can/could affect the winding process. You do not specify your location but it seems to me that Atmos clocks have trouble winding at higher altitudes. That, in turn tends to indicate that they have an altitude limit. I have heard of Atmos clocks operating properly in Denver (5280+/- ft altitude) but not in, say Evergreen with is 7,165 feet. I have found that bellows measurement is not always a good indication of bellows health but that may have to do with altitude here. I could not speculate the operation in New Orleans.
You mentioned that you tried a known good bellows in the clock. What basis did you use to determine the second assembly was good?
Six months run time is an indication that everything is working except the winding mechanism. Atmos clocks will sometimes run up to six months after the winding mechanism has failed or if the winding mechanism is inoperable and someone has manually wound the clock.
In what condition was the winding mechanism when you first saw the clock? Did you find it partially wound? Did you find it completely unwound?
Many of the things we do to clocks make the clock repair person or the owner feel better but do not do much for the operation of the clock. Sometimes those measures introduce factors that may stop the operation of a clock. I know that a dose of WD-40 to an Atmos clock will cause it to fail in short order, regardless of condition or altitude.
Best of luck with the clock,
Dick

Sir,
I’m actually very near sea level here in south-east Georgia. Around 100 feet elevation.
As for bellow’s health, all I could go by is measurement of the bellows’ cavity in various temperatures. It will go completely flat when placed in the freezer and then extend to within 22 to 25mm of filling the cavity when at 75 degree room temperature, and at 50 degrees it’s around 35mm. It seems to me like it is functioning as it should. I guess something I haven’t tested is how it responds at higher temperatures.
The clock was in a sorry state when I first received it, but if I remember correctly, it was either fully wound, or pretty nearly there.
I currently have a second Atmos which has been running continually in the same environment for the past two years. I will try removing its bellows and installing them on this clock. See what comes of that.
Thank you for your feedback!

 

[Jonas]

Moved.

Thank you, sir!

 

[Dick Feldman]

I currently have a second Atmos which has been running continually in the same environment for the past two years. I will try removing its bellows and installing them on this clock. See what comes of that.
Thank you for your feedback!

That sounds like a reasonable approach.
Best,
Dick

 

[Jonas]

Thank you all for your responses.

I did find the reason why the clock wasn’t winding. An older post on this forum gave me the clue which lead to the solution.

So it turns out that the optimal operating temperatures for Atmos clocks is from the lower 50 degrees to the lower 70 degrees (f). Since we live in southern Georgia, in the heat of the summer, we keep our house at 76 degrees, which is a few degrees above what is recommended. What really confused me is that I've had another Atmos that works just fine in this environment.

The reason why one Atmos works in the higher temperature range but the other doesn't was rather unexpected. The point of failure is the coil spring inside of the bellows case. As an Atmos ages, that spring tends to weaken, which lets the bellows compress the spring to maximum compression at a lower temperature, which then means that any temperature change above that maximum compression temperature will have no effect on winding. In one of the pictures of my original post, you can see that the spring is fully compressed an normal room temperature.

The Atmos that works in this temperature has a bellows date of 1980 and the Atmos that wasn't winding has a bellows date in the early 1960s. I compared the springs side by side, and it was obvious that the 1980 spring was a bit stronger than the older spring.

I lowered the our house temperature overnight to test my theory, and this morning, as I was shivering in my PJs, the clock was winding just fine!

This sure was an interesting puzzle to figure out!

Edit: to say That after visiting the Lecoulter website, I discovered that the number that was given in the research that I found online isn’t what is advertised by the manufacturer. They advertise it as working from 59 degrees to 86 degrees (f). That notwithstanding, it seems like a weakened spring reduces the actual operating temperature.

 

[Schatznut]

The cool thing is that you've got two clocks so you can run some A/B comparisons.

What happens when you load the big springs with the same mass? Do they compress the same?
What happens when you compare the standing heights of the two bellows over temperature? Do they compress and expand the same?

One way to '"fix" this clock might be to cut a circular shim that would fit between the bellows and the motor canister. I'm thinking maybe cut out of 1/8" hardboard, for example. It wouldn't matter whether the spring was relaxing or the bellows was getting a little weaker. As the bellows weaken due to gradual leakage of the gas inside them, they'll be "thinner" at a given temperature, so shimming would tend to restore the "thickness". And since the force from a spring is proportional to its compression (F=kx), the extra compression (x) might be enough to compensate for any relaxation in the spring constant (k), yielding an increase the spring force (F) back to the nominal value.

 

[Jonas]

The cool thing is that you've got two clocks so you can run some A/B comparisons.

What happens when you load the big springs with the same mass? Do they compress the same?
What happens when you compare the standing heights of the two bellows over temperature? Do they compress and expand the same?

One way to '"fix" this clock might be to cut a circular shim that would fit between the bellows and the motor canister. I'm thinking maybe cut out of 1/8" hardboard, for example. It wouldn't matter whether the spring was relaxing or the bellows was getting a little weaker. As the bellows weaken due to gradual leakage of the gas inside them, they'll be "thinner" at a given temperature, so shimming would tend to restore the "thickness". And since the force from a spring is proportional to its compression (F=kx), the extra compression (x) might be enough to compensate for any relaxation in the spring constant (k), yielding an increase the spring force (F) back to the nominal value.

That idea would work for a weakened bellows, but would be counterproductive for a weakened spring. The mass (thickness) of the spring material pressed together is what stops the bellows when the spring is weak. This means that once the bellows has fully compressed the spring, it can go no further without some mechanical failure if the bellows container.

 

[svenedin]

Very interesting. I presume you are going to replace the spring?

 

[Schatznut]

That idea would work for a weakened bellows, but would be counterproductive for a weakened spring. The mass (thickness) of the spring material pressed together is what stops the bellows when the spring is weak. This means that once the bellows has fully compressed the spring, it can go no further without some mechanical failure if the bellows container.

So another question - did you find that at the ambient temperature of your home the spring was fully compressed?

At equilibrium, the forces balance, and that equilibrium is driven by temperature. Gas compresses; metal does not. Once the system has the spring fully compressed, any increase in ambient temperature will only continue to raise the gas pressure in the bellows. We can stipulate that if the spring is fully compressed, the bellows is doing its job. Considering the range of the bellows is what, 15mm or so (I don't remember the range offhand), introducing a shim of 3mm would increase the spring force at a given stackup (spring position plus shim thickness, if any) and have the effect of raising the temperature range over which the bellows moves at the expense of a slightly decreased range of travel. Because of the ratchet in the spring winding mechanism, we see that if the motor moves due to changes in ambient temperature, whatever the mean of that ambient is, then the mainspring will be wound.

The thing I'm tripping over is that I have two Atmos clocks in our home, and my wife keeps the temperature between 75-77 degrees (below 75 and she's freezing. above 77 she's burning up). They both work as they should. One of them (built in 1968) quit recently and I overhauled it. The mainspring lubricant had dried out; following cleaning and relubrication (and a cleaning of the movement) it's running normally again.

 

[Jonas]

Very interesting. I presume you are going to replace the spring?

That depends on if the friend that I repaired the clock for keeps his place above 72 degrees or not. If he keeps his home cooler than we do (which I think he does), then there won’t be a pressing need.

 

[Jonas]

So another question - did you find that at the ambient temperature of your home the spring was fully compressed?

At equilibrium, the forces balance, and that equilibrium is driven by temperature. Gas compresses; metal does not. Once the system has the spring fully compressed, any increase in ambient temperature will only continue to raise the gas pressure in the bellows. We can stipulate that if the spring is fully compressed, the bellows is doing its job. Considering the range of the bellows is what, 15mm or so (I don't remember the range offhand), introducing a shim of 3mm would increase the spring force at a given stackup (spring position plus shim thickness, if any) and have the effect of raising the temperature range over which the bellows moves at the expense of a slightly decreased range of travel. Because of the ratchet in the spring winding mechanism, we see that if the motor moves due to changes in ambient temperature, whatever the mean of that ambient is, then the mainspring will be wound.

The thing I'm tripping over is that I have two Atmos clocks in our home, and my wife keeps the temperature between 75-77 degrees (below 75 and she's freezing. above 77 she's burning up). They both work as they should. One of them (built in 1968) quit recently and I overhauled it. The mainspring lubricant had dried out; following cleaning and relubrication (and a cleaning of the movement) it's running normally again.

Yes, the issue was that the spring was fully compressed (and immovable by the bellows) at our homes ambient temperature.

I’m trying to think of a good way to explain the mechanics of it to you …

So as you said, gas is compressible, but steel, not so easily. Once that thick counterbalance spring compresses fully, you basically have a metal tube that the bellows is pushing against. I actually did something very ill advised before I discovered that. I wanted to test whether the bellows cavity would close further in a warmer environment than the house temperature, so I heated the oven to it’s minimum temperature, turned it off and let it cool down for a while, then put the bellows, inside its case, in the oven For a few minutes. This built up enough pressure in the bellows to cause a visible bulge in the front of the case (which thankfully shrank back again!) that could have very easily caused failure of the casing, resulting in a mechanical explosion (again, ill advised). I measured the depth of the cavity in that state, and it was still exactly at the 22mm that it had been at room temperature.

Your two Atmoses very likely have more strength in their counterbalance springs than mine does. If you consider it, the greater force that the spring can exert against the bellows, with the compressable gas, BEFORE the spring is fully compressed, the greater temperature flexibility you will have.

I hope that helps demonstrate the situation to you.

 

[etmb61]

This won't help, but Le Coultre had a different gas in the bellows for warmer climates. The motor springs (the big spring) have the same rate. The higher temp gas has a lower vapor pressure. It's in the Atmos literature somewhere.

Eric

 

[Robert Gift]

... I will try removing its bellows and installing them on this clock. See what comes of that. ...

Are the bellows interchangeable?
Good test!
Have you measured the bellows in usual (typical) temperatures and barometric pressures?
Inside the glass envelope, I thoughthathe bellows were influenced only by barometric pressure.

 

[Jonas]

Are the bellows interchangeable?
Good test!
Have you measured the bellows in usual (typical) temperatures and barometric pressures?
Inside the glass envelope, I thoughthathe bellows were influenced only by barometric pressure.

The bellows are indeed interchangeable. I swapped them out, and my other clock’s bellows were able to wind the clock in our normal home temperature.
The bellows are actually influenced mostly by temperature changes and a very small amount by barometric pressure.

 

[Robert Gift]

The bellows are indeed interchangeable. I swapped them out, and my other clock’s bellows were able to wind the clock in our normal home temperature.
The bellows are actually influenced mostly by temperature changes and a very small amount by barometric pressure.

Thank you.
Since most homes are nowell temperature-controlled, (except ours), I would not expect minimal temperature variations to accomplish much.

 

[TQ60]

I I recall correctly the claim is a 2 degree change can run for 2 days.

The simple observation is to see where the chain is located on the winding wheel as it indicates the position of the bellows.

If it is always full then it may be over charged.

It is easy to measure spring strength with a scale.

We had a similar issue with the winding spring.

Some bending fixed it.

 

[etmb61]

If it is always full then it may be over charged.

Over charged? What do you mean?

Eric

 

[TQ60]

The photos show the bellows working to. Full height compressing the spring but it also does not seem to go short enough.

Too much gas could cause this or possible that. Someone charged it and too much normal air so lower temp does not condense properly.

Toss it in the freezer and it should fully compress.

 

[Gyro Gearloose]

Dick, Based on my own experience I'm going to have to take exception to what you wrote:

"Dick Feldman, post: 1570434, member: 79"
... it seems to me that Atmos clocks have trouble winding at higher altitudes. That, in turn tends to indicate that they have an altitude limit. I have heard of Atmos clocks operating properly in Denver (5280+/- ft altitude) but not in, say Evergreen with is 7,165 feet.

I live at 9000 ft. elevation here in the mountains of Colorado, and my Atmos runs perfectly with no problems. It was shipped here from sea level and it ran perfectly from the get-go. I've researched this in vain attempting to find out what the actual altitude limit is for the Atmos clocks, but so far have not found the answer.

I'm curious to know about the clock you mention that lives in Evergreen that you heard of?

~Frank