Mending an old brass click spring

Discussion in 'Clock Repair' started by NigelW, Mar 18, 2019.

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  1. NigelW

    NigelW Registered User

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    The spring of the click which engages with the going train fusee is broken and I want to mend it rather than make a new one as I think the part is original and thus some 300 years old.

    I managed to remove the spring, which was riveted in, and am thinking of soft soldering a thin price of brass to its outer diameter, although I have not quite worked out how to hold the work while doing so to maintain the geometry.

    The first pic shows how it was before I tied to remove the rivets, with the piece still just managing to stay together. The second shows the separated parts. Unfortunately the vibration caused while I was removing them (rather gently I should add, using a staking set) must have been the final straw and they separated.

    Any ideas?

    54375851_10156291116143473_722215355165966336_n.jpg?_nc_cat=100&_nc_ht=scontent.flhr3-2.jpg 54396396_10156291116183473_3094598772278165504_n.jpg?_nc_cat=111&_nc_ht=scontent.flhr3-1.jpg
     
  2. shutterbug

    shutterbug Moderator
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    Is it brass or steel? Soldering steel will anneal it and you might lose too much spring action.
     
  3. R. Croswell

    R. Croswell Registered User

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    I would consider using the damaged part as a pattern and just cut out a new part from sheet brass.

    Now I did "fix" one of these some time ago by thinning a section of wide part the length of the broken off piece. Then reposition the part so it reaches the click. You will need to drill new holes to secure the part in the new position. It worked OK, but reproducing a new part would keep it more original looking. I would not try to reattach the broken piece.

    RC
     
  4. NigelW

    NigelW Registered User

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    It's yellow brass.
     
  5. novicetimekeeper

    novicetimekeeper Registered User

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    A repairer I know had a Johannes Fromanteel bracket in where the click springs had cracked . He made two new ones from some cast yellow brass which he hammered and cut to shape.

    That clock was lovely btw, the first time I ever got that close to something so special. It was as a result of meeting that I decided to get a verge bracket, though mine are somewhat more modest.
     
  6. NigelW

    NigelW Registered User

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    Thanks for the suggestions. It sounds like I may have to make a new spring, which I am rather reluctant to do, but I will need to commission quite a few yellow brass castings in due course as I have have no experience of casting and I don't fancy trying. I am hoping to use CAD, combined perhaps with 3D printing, to make the models - or maybe the casting company can just take the CAD file and do the whole thing themselves?

    If making a new spring is the answer is there any harm in at least trying the soldering option first? I guess the greatest risk is of the spring breaking again when in use which I imagine could cause some other damage.
     
  7. shutterbug

    shutterbug Moderator
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    Soldering won't hurt anything, so I would go for it. It might even work :)
    If I had looked at the title closer, I wouldn't have asked what material it was made from! :rolleyes:
     
  8. Uhralt

    Uhralt Registered User
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    You could remove the rest of the spring and then reduce material from the back of the "ring" in the thickness of the spring for half an inch or so. Then you can solder a strip of brass with the dimensions of the old spring (just half an inch longer), formed in the shape of the old spring, to this reduced area. That gives you a nice, large surface for soldering. If done well, the repair would be barely visible.

    Uhralt
     
  9. R. Croswell

    R. Croswell Registered User

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    I believe you answered your own question - the risk of further damage is too great. I wouldn't fool with trying to cast this part. Either use a jeweler's saw to cut out a new part from sheet brass, or execute the repair described by Uhralt above.

    RC
     
  10. Bruce Alexander

    Bruce Alexander Registered User
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    This might work, I've never tried it....

    Carefully superglue the parts together

    Set the glued spring in plaster (or dry wall compound?) so that there is a partial impression which will hold the parts in relation to one another but still allow removal.

    Clean and prep the parts

    Relieve the broken area so that plaster doesn't interfere with the flow of solder. Alternatively, you might add a little extra superglue around the joint before taking your plaster "impression".

    Proceed with low-temp soldering.
     
  11. R. Croswell

    R. Croswell Registered User

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    You aren't really serious are you?

    RC
     
  12. Bruce Alexander

    Bruce Alexander Registered User
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    Please enlighten me. Why wouldn't this work?

    If the solder joint isn't going to be strong enough, include a strap across the joint in your set up.

    The gypsum "mold" would hold the joint for soldering.

    Like I said, I haven't done so but I can certainly try it.
     
  13. novicetimekeeper

    novicetimekeeper Registered User

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    You don't need to cast a new spring, you need some cast brass the right size to make it from. You just need a bit big enough to cut what you want. The original wasn't cast as a component, but it was cut from cast sheet. There were no rolling mills, sheet only existed as a thin flat casting you hammered and cut to shape. You can use an offcut of round cast bar of a piece of thicker cast sheet. A dialplate won't be useful as a donor but you can probably pick up some movement plates that are thick enough.
     
  14. Bruce Alexander

    Bruce Alexander Registered User
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    Hello Nigel,

    When I was studying dental lab techniques we were introduced to the use of "Soldering Investments". These are gypsum (plaster-like) products specifically made to form a mold or matrix around metals to hold them for soldering. Examples might be to hold components of a dental bridge in strict relationship to one another for joining. In my case I would sometimes use it to solder tighter contacts between adjacent teeth.

    I suggested use of plaster or dry wall compound simply because it is commonly available. These products are not formulated for high temperature but you proposed the use of soft, low-temp solder. One of the things you'd have to be careful of is excessive amounts of water/moisture trapped in the gypsum matrix. If it is not thoroughly dried, moisture/steam will escape while your trying to solder which will lead to problems. Dental Labs would burn off excess moisture in a low temp oven once the gypsum product had enough time to completely set up.

    As proof of a very old concept, I've quickly run through a demonstration using wall plaster. Since I was just rushing through a quick demonstration, I did have a problem with moisture but it burned off enough that I got the joint soldered on a second attempt. If you were to try this method, I'd strongly recommend trying it on scrap brass a few times to make sure your materials and methods work. Drywall compound might not work.

    Just one option that I thought might address your original question. There are probably options depending upon what arrows you have in your Quiver which might work better in your shop.

    Cheers

    Yes, are you?

    Parts.JPG Glue.JPG Quick Investment.JPG Soldererd.JPG Underside.JPG Side.JPG
     
  15. David S

    David S Registered User
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    I like your idea Bruce. I was wondering about the moisture and also thought about just baking it for a while. One never knows when we will encounter a weird shape and want to hold it for processing, so this is just another method. And thanks for taking the time to demonstrate.

    David
     
  16. Bruce Alexander

    Bruce Alexander Registered User
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  17. NigelW

    NigelW Registered User

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    Some really interesting ideas here - thank you.

    For the soldering option I had thought of making some kind of former to hold the piece while soft soldering with a large soldering iron, perhaps out of wood, my thinking being that metal would conduct away too much heat, although I am not sure how the wood would behave when the piece was heated! The plaster option sounds interesting. My tutor had suggested soldering but the more I think about, and reading your advice, the more I am inclining to making a replacement part. It would in any case be a good exercise.

    My understanding about yellow brass (which I have only previously used in the form of cast bar to make a couple of small parts for a 17th C lantern clock) is that for most purposes it needs to be work hardened first by hammering. If this is right, making a new part could be done in one of two ways: cutting out an oversized blank from sheet, hammering it, then turning and filing it to shape, or casting an oversized blank before doing the same.

    I have now found a supplier in the UK who has cast brass sheet in 2,3,4,5, and 9mm thicknesses. The finished spring is 3/32" thick or about 2.5 mm, so the question is how much thicker does the blank need to be to allow for the reduction in thickness when hammering and then for machining?
     
  18. Bruce Alexander

    Bruce Alexander Registered User
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    Hi Nigel,

    Obviously there's only one way to keep the original part but this is for a click spring and you certainly don't want any failures so you must do what you feel will be best in your shop and in your hands.

    Just out of curiosity, how did your tutor suggest you solder the piece?

    Regards,

    Bruce
     
  19. NigelW

    NigelW Registered User

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    He didn't elaborate. He is quite a distinguished horologist who looks after a number of museum collections. I will press him on this next time I see him.
     
  20. David S

    David S Registered User
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    You are absolutely correct in wanting some sort of support with low thermal conductivity hold the parts. Bruce's method of using plaster should be good as would be wood as long as it stands up during the heating process.

    Jewellery supply places sell solder blocs that are inexpensive and designed for this purpose. The one I like the best is full of through holes which allows me to hold parts on the block with thin wire or pins. For a flat part like this click spring it would be ideal.

    stuff soldered with brown flux and ee solder.jpg
    here two small nails are secured for silver brazing
    nail heads silver brazed fixtured.jpg

    David
     
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  21. NigelW

    NigelW Registered User

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    Thanks David. This looks like a good tip.
     
  22. novicetimekeeper

    novicetimekeeper Registered User

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    I don't know the answer, and would be interested if anybody does. However I have a feeling it doesn't involve too much thickness reduction.

    On the first 8 day I ever bought it has a rack return spring that was made by a local repairer from cast yellow brass he hammered. Yes I know you can buy blank comma foots but I rather liked the idea of doing it the right way, and it is a great colour match. Has been running for years no problem.

    I know Delaunce did some work on hamming escape wheels to improve hardness, he was involved in early work on making clocks with seconds subsidiaries, but I have not seen any figures regarding the technique. It does sort of suggest the wheels might have been cast and then hammered, I have seen rag on crossing outs before which made me wonder about that.

    I can tell you that dialplates are not reduced in thickness by planishing very much at all. You can see this on Northern longcase dials with the cast cutouts, as you can see very little distortion of the cutouts as evidenced by the rag you can see on some of them.

    I get the feeling that something around the 4mm option might be what you want, but I have no info to support that.
     

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