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StuartBaker104

Barograph

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There’s no section on here for barographs, but I’m going for clock corner and calling it a clock with a complication :)

Santa brought me one of these as another project (because I completed so many of the ones I planned to do last year... honest...). Has anyone here ever worked on the bellows from these? At least one of the capsules in this set needs to be re-vacuumed. It looks like it’s been resoldered but has air in it and makes the stack too high, also it won’t respond correctly to pressure changes like this, but I’m not expecting a perfect calibration here!

I’m thinking that I could make up a small brass tube, insert it into the solder joint, suck the air out then crimp it closed before sealing with a blob of solder. It looks like this is how the rest are formed.

What I don’t know is how much of a vacuum I need to achieve.  Will it be enough to remove as much as I can with a large syringe or am I going to need to acquire a better vacuum pump? It feels as though if these were really pumped out then the plates would collapse? Thoughts welcome, shared wisdom, knowledge or experience very welcome!

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49 minutes ago, StuartBaker104 said:

Thanks vin - I can’t find the surveyors altimeter post... will it help me if I do?

the post was for a barometer.  couple yrs. ago .I will look for my pocket  altimeter to get the proper name.

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Have you tested the barograph to see if its working at all? in your photos the recording arm is set far too low have you tried adjusting it with the large brass knob above the stack to bring the arm up onto the chart. Simple way to see if the aneriod capsules are working is to put the barograph in a large clear plastic bag leaving air in the bag seal at the top and squeeze the bag if the stack is working the arm will move as you squeeze and increase the pressure and fall again when you release.

Aneriod capsule stacks can still be bought but you would be hard pressed to get a stack of 7 but stacks of 6 or 8 can be bought but are expensive.

 

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Thanks for the inputs...

OH - good news is that the clock movement is running, despite the seller saying it wasn’t. It’s  pretty hidden inside the drum and all I can see is the platform through a regulating hole. Amplitude is pretty low, but it’s a lever escapement so should just need a good clean and service.

WLS - I haven’t tested all of the capsules, but to get the right range of movement I assume they all have to work. I have established that the lowest one is sealed but filled with air and therefore too high and will not compress properly under external pressure. There isn’t enough adjustment on the brass knob to get the pen onto the chart. I could adjust the arm on its pivot pin but I assume the first lever arm  (connected to the bellows) should be more or less horizontal in the middle of the pressure range. I have seen new capsule stacks for sale but they seem to cost about what I paid for this project... and the fun is in the learning, not just getting a working item :unsure:

 

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@StuartBaker104; this morning I pulled my barometers book from "Bert Bolle" out of my pile. Bert Bolle is a Dutch passionate collector of antique barometers and even though his book deals primarily with antique barometers, there is a section about aneroïdebarometers and their history.

This very hard to get book is written in Dutch and I will try to translate some of what Bert highlights about aneroïdebarometers, things you perhaps may already know or perhaps you may not ....?

The idea of an aneroïde barometer was born in the late 17th century by a German scientist Gottfried Wilhelm Leibnitz. A century later a France man Nicolas Conté constructed a primitive version, but due to all sorts of problems, the idea went back into the freezer.  It wasn't until 1840 that the France man Lucien Vidie came along who constructed and named the first crude form of aneroïde barometer. In a patent of 1844 the "Vidi-box" was mentioned.

The air was as good as possible removed, but to prevent that the box would collapse, steel spring were placed inside the box. Later improved models had the springs outside the box and the first models of aneroïde barometers were sold in the UK around the 1850's. Already around 1860 the system was so far developed and reduced in size that they were sold in pocket-size (Negretti & Zambra). These little barometers were worn, on a chain, in the other waste-coat pocket opposite the pocket-watch. They also were developed for use on sea and in mountains. The smallest made was only 2cm in diameter..... a small loupe was supplied to read the scale :) For homes the much bigger Banjo barometers were produced.

The first mercury barograph came about in the 1680's; Robert Hooke and again Negretti &  Zambra. The first aneroïdebarograph was introduced around 1867 by the Paris maker Breguet.

As for the technicalities, Bert writes;

The first Vidi boxes were soldered close after as much air as possible was removed out of the box. The accuracy was reasonable good, despite all the friction in the numerous links in the lever-mechanism. A little tap on the glass was required to get the needle jump to the correct spot. The aneroïde barometers were calibrated against mercury barometers. Temperature changes had an influence on the box and springs, so compensation systems had to be introduced. Bi-metals in the leverage system to compensate for the temperature fluctuating spring tension and a little air, or better Nitrogen gas (which doesn't erode the metal) in the vidi-box. An increase in temperature would expand the gas, compensating for the lost of spring power. Just like with the bi-metal, the compensation was only accurate at one spot on the scale. Reasonable modern boxes are made of  "Ni Span C". This alloy allowed a vidi-box to be made which is not sensitive for temperature changes.

Than there is the hysteresis in the linkage system caused by friction and the elasticity of the metals used. For the best accuracy, the aneroïde barometer has to be calibrated against a mercury barometer and a correction-factor, for that particular aneroïde barometer, has to be determined.

As for barographs, the pressure of the pen on the paper, ink and paper used is of great influence.

The rest of the book is meanly about all sort of antique collectible barometers, but this part may be of some interest to you?

BTW; here a link to Bert Bolles museum and his world famous water barometer: https://en.wikipedia.org/wiki/Bert_Bolle_Barometer

Roland.

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Thanks Roland

6 hours ago, Endeavor said:

The air was as good as possible removed

I think this is the key point here. If I can evacuate it down to the same height as the others then I think I’ll be winning.

Unfortunately before I play with this I have to reassemble the Pierce chrono which has been on my bench for months... and before that I have to do my tax return :wacko:

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Time for an update on this... which appeared to have suffered a few challenges over the years.

1. Bellows

Some research led me to discover that I needed about 1”Hg vacuum inside the leaky capsule.  We still make some old bellows at work and have equipment which might have done this job... a vacuum bell jar with an inductive heating coil inside.  Sadly I only had one part to practice on and I didn’t want to ruin it... nor break the equipment!

So I found the original hole and made a new short piece of brass pipe and soldered it into the capsule in the same way as the others

 

D3677C56-5C35-476B-9AF6-41FCE4BC3F16.thumb.jpeg.72d68d3621d7cdf1bc648973f4c7c63a.jpeg

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and made a vacuum pump from a syringe and bicycle tyre valves. This all worked well and whilst I couldn’t measure the vacuum, the capsule contracted down to the same height as the others with the best vacuum I could get.  All was good until I tried to crimp the brass tube so I could cut it off and solder closed.  I had hoped that it wouldn’t leak in this process, but sadly I was wrong.

If I’d had plenty of brass tube then I could have had a few more attempts, but I’d had to make what I had from a brass bolt and didn’t fancy turning loads of them, even if I’d had any more suitable bolts.

In the end I decided to do a temporary fix until I had more time to play, so I held the capsule compressed in a vice and soldered it shut. When released from the vice it retained about 50% of the compression. So it now has a little more air than it should do inside which will make it slightly temperature sensitive, but probably no other effects.

The end piece of the bellows which connects to the lever arms was a home made replacement (possibly the bellows has been taken from another barograph), and the link pin hole was in the wrong place. I modified that today after the pictures below were taken.

2. Case

I had to strip all this apart as it was warped and the joints were loose, plus the drawer didn’t fit properly. I managed to retain most of the original varnish then waxed with Liberon black bison paste

3. Lever mechanism

I stripped all this down and cleaned the brass and polished all the pivots. Cleaned the dried up ink out of the nib and the bottle. All the brass had a grained finish so I refinished in the same way, without making it look brand new.

I was going to use horological lacquer on the brass, but it didn’t seem to be finished that way in the first place so I opted for a coat of clockshine wax from Meadows and Passmore. I've never used that before so we’ll see how it goes. I can always strip it and lacquer later, but stripping off lacquer in the future would be a pain.

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Bought new charts and ink from Barometer world and voila...

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I still have to service the clock but since it is going I wanted to run it for a couple of weeks to see if it has any issues.

I’ve had it running for a few days and made some calibration adjustments (there are a couple of option holes on the linkage); all seems good now but really need some bigger swings in atmospheric pressure to be sure.

More to follow when I strip the clock down (one day)

 

 

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@StuartBaker104 Very nice Stuart! Another learning curve and experiences under your belt :) Lets hope it now has become, next to a very nice decorative piece, a functional piece as well !

Believe it or not, I'm now into stripping / restoring / reassembling a high quality sewing machine and learn how to sew / make outdoor equipment (tarp, hammock etc) ......... in the last couple of months no time spent on watches / clocks. There is so much to learn in the whole spectrum of mechanical things and (old) skills ............ ;)

Edited by Endeavor

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24 minutes ago, oldhippy said:

 

That’s looking good. After polishing the brass, did you lacquer the pieces?

I decided that brush lacquer would be very difficult to get right on the combination of things that needed to move and not move and a large flat plate and I didn’t want to use a spray lacquer as they are very hard to strip next time round.

After some research I bought this (sorry for the wierd looking picture I had to do a pnorama shot and twist the bottle so you can see all of the label). Will see how it stands the test of time...

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2 hours ago, Endeavor said:

@StuartBaker104 Very nice Stuart! Another learning curve and experiences under your belt :) Lets hope it now has become, next to a very nice decorative piece, a functional piece as well !

Believe it or not, I'm now into stripping / restoring / reassembling a high quality sewing machine and learn how to sew / make outdoor equipment (tarp, hammock etc) ......... in the last couple of months no time spent on watches / clocks. There is so much to learn in the whole spectrum of mechanical things and (old) skills ............ ;)

Yes, there was a lot more learning in there than I expected. You will have fun with the sewing machine. I serviced an old sewing machine years ago for my wife and it took quite a while to understand what effect all the adjustments had. Interestingly she now has a much newer machine as she wanted more features, and that one has virtually no adjustments... presumably manufacturing accuracy has improved to the point where adjustment in the factory is not necessary and it’s designed to be thrown away when worn out :angry:.

The barograph looked like such a simple mechanism, but understanding where the friction comes from to keep the hysteresis down is really important. It’s very easy to set the pen pressure too high and even that has a big effect. Also, it is recognised that the important thing a barograph does is provide a trend, rather than absolute point accuracy, so no need to chase my tail too far on that... so over night and this morning the pressure is rising and the weather is set fair :woohoo-jumping-smiley-emoticon: .  The gap in the trace yesterday is where I took it apart again to put a new link pin hole in the bellows attachment.

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On ‎26‎/‎12‎/‎2017 at 4:32 PM, StuartBaker104 said:

There’s no section on here for barographs, but I’m going for clock corner and calling it a clock with a complication :)

Santa brought me one of these as another project (because I completed so many of the ones I planned to do last year... honest...). Has anyone here ever worked on the bellows from these? At least one of the capsules in this set needs to be re-vacuumed. It looks like it’s been resoldered but has air in it and makes the stack too high, also it won’t respond correctly to pressure changes like this, but I’m not expecting a perfect calibration here!

I’m thinking that I could make up a small brass tube, insert it into the solder joint, suck the air out then crimp it closed before sealing with a blob of solder. It looks like this is how the rest are formed.

What I don’t know is how much of a vacuum I need to achieve.  Will it be enough to remove as much as I can with a large syringe or am I going to need to acquire a better vacuum pump? It feels as though if these were really pumped out then the plates would collapse? Thoughts welcome, shared wisdom, knowledge or experience very welcome!

3267EE8F-8485-4DA0-ADF3-E58D4F67BCC9.thumb.jpeg.505855b9fd6ebfe18f5e414e558a4de6.jpeg

2DD047C6-60DF-44AF-AA73-3E5AFF912DBB.thumb.jpeg.606e70034d4b34fb7c90bf3ee6ffb3c3.jpeg

That is a beauty, although I have never worked on one..

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On 12/27/2017 at 8:06 AM, oldhippy said:

I have only restored the clock movements in these. They are very similer to a french/english platform timepiece.

Hiya I have just bought a barograph in great condition but when I try to remove the clock using it's knurled screw it unscrews so far then it all seems to turn. Can you help please?.

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Thanks for posting that - I’ve always loved barographs. I had similar issues with a Baro I found in an auction. I found sucking it hard and crimping the bellows did the job! The movement was in good nick, just needed a bush or two.

I didn’t lacquer the brass - I just used renaissance wax (less fuss!)
 

 

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