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Help [Amateur] Repairing a Junghans W.278 Mainspring Axle

Sir_McMuffinman

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Greetings all. I am a complete amateur, and primarily here in search of help since I can't find any other good sources. Per the tips thread, we are located in Texas (I'll address the other talking points throughout this post). I want to be up front and apologize for what I'm sure will be innaccurate terminology and/or understanding of clock mechanisms. I did my due diligence by checking out the terminology thread, but I don't think the parts I'm asking about are directly identified.

I'm requesting assistance/knowledge/advice with a Junghans W.278 mantle clock. Based on the stamp on the back, I believe it was made in June 1952. There's also a stamp that says "187/35 83", which based on this post tells me that the BPM is 187 with a 35-tooth escape wheel and 83-mm long pendulum [See Figures 1thru 4].

This clock was gifted to my grandfather's family in 1953, and has been in the family ever since. Some of the following details are a bit foggy... Somewhat recently (3-6 months ago, as far as I'm aware), the clock started malfunctioning. Despite the many years of my life I've spent visiting my grandparents, I cannot remember exactly how often it would chime- I believe it told the time every hour and rang once every half-hour. Well, from what I was told, the clock started malfunctioning by ringing every quarter hour. From what my grandparents told me, I wasn't able to determine if this was the "single chime" ring, or the "telling the time" ring.

My grandfather is very much an old-timer. Ancient but time-tested tools, always the "if it ain't broke, don't fix it; if it is broke, fix it yourself" mentality. He's always been a tinkerer, extremely hands-on with absolutely anything mechanical. In his garage, he has a lathe, drill press, table saw, and pretty much any other standard tooling item you might find in a tinkerer's workshop- but nothing as precise as I'd imagine would be found in a clockmaker's workshop. So, he began to do what he always does, which is: take the thing apart, learn how it works, find the problem, fix it, and put it back together. He told me that he narrowed the source of the problem down to what I believe is called the "mainspring barrel". I'm unsure exactly how he performed this troubleshooting, but I suspect it was something like inspecting each part and visually determining when the malfunctions occurred. He disassembled the barrel and began to work on the axle... it's at this point where I need help. I am entirely unsure of how this part is intended to function, but based on my intuition I understand that the coil is the spring that is wound up, and that the axle is the part that receives the winder.

He was struggling to explain what he thinks the solution is, but he was fixated on the idea that it involves machining (or otherwise modifying) the end of the axle shown in Figures 5 and 6 so that it has a protrusion that would fit correctly in the wedge-shaped notch shown in Figures 7 thru 9. He mentioned that he thinks he needs to notch a small groove underneath the protrusion, and that the protrusion needed to be in the right shape, but my lack of understanding with the way it's supposed to work makes it even harder to understand what he's trying to say and comprehend the solution. Regardless, he's stuck and currently unable to solve this problem himself, and it's distressing to him. They asked a clockmaker in town, but they said they wouldn't be able to work on this (I asked for clarification if the clockmaker "could not" or "would not", and my grandparents said they "would not").

---------

If anyone here could provide assistance in the form of diagrams/drawings and explanations of what this part is and how it's supposed to function, I would very much appreciate it. Additionally, if anyone could suggest that this might be the true source of the problem and that it wasn't something else that malfunctioned, that would be comforting to know as well.

This means a whole lot to our family, and specifically it means a ton to me. I've grown up on his lap tinkering and building random gizmos and models out of wood, and he's half the reason I've become a mechanical engineer. I owe so much to him. Anything I can do to help keep my him more comfortable is absolutely worth it.

Figure 1.jpg Figure 2.jpg Figure 3.jpg Figure 4.jpg Figure 5.jpg Figure 6.jpg Figure 7.jpg Figure 8.jpg Figure 9.jpg Figure 10.jpg Figure 11.jpg
 
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shutterbug

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Your grandfather is quite the tinkerer! What he has diagnosed as the problem is pretty close. The inner coil of the spring is not catching the winding arbor. You can reach in with needle nose pliers and force that inner loop to a tighter coil so it can catch. However, the bigger issue is what caused it to loosen so much. Usually it is from a catastrophic sudden release of the spring, which likely occurred when the click failed. Another issue will be the condition of the bearing surfaces, where the pivots turn in the plates. After running so many years, they will need to be bushed, and the pivots polished. But baby steps. See what you can do about the click and the spring, and the old clock might run long enough to ease Grandpa into eternity with less stress. Then see what you can do with it with a more permanent repair. We're here to help ;)
EDIT: It looks like you have it pretty much completely apart, so read "Bushing Using Hand Tools"and and see if you feel up to the task. I think you can do this!
 
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tracerjack

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Is that chewed up metal on the mainspring arbor? And is it broken? The one in photos five and six. Wonder how it compares to the arbor in the other barrel.
 

Willie X

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Close and reshape that inner coil until it's slightly smaller than the arbor. The arbor should snap in place when all is good.

What Bugs said, your ratchet/click mechanism is faulty. Not finding the fault will set you up for a replay.

Willie X
 

Sir_McMuffinman

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Thanks everyone for the feedback so far. I've got a couple questions/comments below just to clarify a few things.

However, the bigger issue is what caused it to loosen so much. Usually it is from a catastrophic sudden release of the spring, which likely occurred when the click failed.
Based on the Terminology thread, I assume you're saying that the failure was actually the ratchet/click mechanism that was attached to the mainspring arbor, and not so much the mechanism inside the barrel itself. I didn't get a picture of those parts when I was with him, but I'll see if he can take a few more. That said, what should we look for (i.e. how would we determine that was truly the part that failed)? And to be clear, failure of that mechanism would result in the chimes ringing more often?

Another issue will be the condition of the bearing surfaces, where the pivots turn in the plates. After running so many years, they will need to be bushed, and the pivots polished.

EDIT: It looks like you have it pretty much completely apart, so read "Bushing Using Hand Tools"and and see if you feel up to the task. I think you can do this!
I'm unsure whether or not the inner diameters and pivot locations are in good condition, and don't really know the limits of what would be considered "good enough". I wasn't specifically looking for it, but I don't remember seeing any holes that were noticeably damaged. I'm also unsure of his ability to fabricate bushings, but we can cross that bridge if/when we get there.

Is that chewed up metal on the mainspring arbor? And is it broken? The one in photos five and six. Wonder how it compares to the arbor in the other barrel.
I think he tried to sand/grind away material, or something. Again, he was struggling to find the words to explain what he did and why he did it, but from what I gather he was trying to shape it into what he thought it should be. Without knowing what it should ideally look like, it's a bit more difficult for me to understand what went on here.

I also thought the same thing about the other arbor and suggested that we partially disassemble that one to see how it worked. However, he's very hesitant to disassemble something that appears to be working fine, and it's hard to argue with that logic. I really wish I could see what it looked like though, as I believe that would allow us to know exactly what needs to be done for the mainspring arbor.

If he's gone too far with the existing arbor and destroyed it, I think he planned on making a new one with the tools he has... it would probably be jerry-rigged and rugged, but he would make it work because that's just how he is.

Close and reshape that inner coil until it's slightly smaller than the arbor. The arbor should snap in place when all is good.

What Bugs said, your ratchet/click mechanism is faulty. Not finding the fault will set you up for a replay.
Kinda back with what shutterbug suggested with the needle nose pliers, I assume you are saying to manually twist the coil around until it's tight enough? Perhaps by holding the pliers stationary and twisting the barrel around would be the easiest way to do this. As for the arbor, as I discussed above, I think he's machined it away from its original form since he thought that was the source of the problem, and it may not work as intended anymore.

I'll suggest inspecting and taking pictures of the ratchet/click mechanism to see if there's anything outstanding. Any suggestions as to what we might look for in particular?
 

Willie X

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Damaged/worn ratchet teeth, worn or bent pawl tip, weak or damaged click spring, to name a few.

Might be a good idea to just put it back together and send/take it to a professional clock repair person.

Willie X
 

Kevin W.

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At this point, not knowing what has been done. I would take it to a reputable clock repair person, it most likely needs bushings as well, and it can all get repaired at the same rime, and save this family heirloom.
 

tracerjack

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What has me confused is the very short tip on one side of the mainspring arbor. The hook usually goes in the middle of the barrel, which means there is quite a bit of metal shaft on both sides of the hook. Now, I haven't seen everything, so maybe this is a new one on me. This is how a mainspring arbor normally looks, but maybe yours is correct.
Winding Arbor-31/32/33 Barrels
 

Dick Feldman

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You came to this board with almost zero experience in repairing clocks and asked for help. I would suggest you take that good advice.
This board is populated by people with many levels of experience but my guess is that you are drawing from a knowledge pool of more than a thousand years.
It has been stated that what you see is likely the result of a click assembly failure. If you do not solve the root problem, it is likely that problem will again raise its ugly head.
In addition, when clocks are wound, all gear trains (main springs) are wound. If, over the history of a clock, a click assembly on one train has failed, does it not seem logical the other one or two click assemblies are due for failure?
Both you and your grandfather are into this repair well beyond your capabilities. Regardless of the reasons, if you value that clock, take it to a qualified professional. If your goal is to have a long lasting, safe and reliable clock, that will be a safe bet.
JMHO
Dick
 

Sir_McMuffinman

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You came to this board with almost zero experience in repairing clocks and asked for help. I would suggest you take that good advice.
This board is populated by people with many levels of experience but my guess is that you are drawing from a knowledge pool of more than a thousand years.
It has been stated that what you see is likely the result of a click assembly failure. If you do not solve the root problem, it is likely that problem will again raise its ugly head.
In addition, when clocks are wound, all gear trains (main springs) are wound. If, over the history of a clock, a click assembly on one train has failed, does it not seem logical the other one or two click assemblies are due for failure?
Both you and your grandfather are into this repair well beyond your capabilities. Regardless of the reasons, if you value that clock, take it to a qualified professional. If your goal is to have a long lasting, safe and reliable clock, that will be a safe bet.
JMHO
Dick
I entirely agree, that is in fact why I'm here, because I know this is something we aren't familiar with. I suggested taking this to a professional for repair, but as I mentioned further above the place in town refused to work on it. The next closest place we could have it repaired would likely be more than a few hours away which is why we have been attempting to fix it ourselves. I'm not doubting anyone's advice, and I'm not thinking "oh, we'll just ignore the advice because we can do it ourselves". Again, that's why I'm here, to seek advice on how we could fix this. EDIT: To clarify, I'm saying we're not full of ourselves, and we recognize our limitations. I wouldn't be posting here if we thought we could do it all.

I have absolutely nothing wrong with getting it to a professional, and everyone's responses have more or less confirmed my suspicion that that would be the best way to solve the problem. I'll discuss with my grandparents the possibility of bringing it to a professional place.

What has me confused is the very short tip on one side of the mainspring arbor. The hook usually goes in the middle of the barrel, which means there is quite a bit of metal shaft on both sides of the hook. Now, I haven't seen everything, so maybe this is a new one on me. This is how a mainspring arbor normally looks, but maybe yours is correct.
Winding Arbor-31/32/33 Barrels
Based on the markings at the end of our arbor, I'm thinking he may have cut or ground away the end of the shaft for some reason. This could have been a mistake that he wasn't aware of. I remember checking the fit against the caps of the barrel and noticing how it didn't really sit too well. You're probably correct in that ours should look a bit more like the one you linked. I appreciate your input.
 

tracerjack

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Professional examination of the movement is your best bet. You can look into the NAWCC chapters (listed on this site) for one near you that might be able to point you to someone reliable. If you have an interest in fixing clocks, you can educate yourself through books or videos. I did. You could then trouble shoot the movement yourself or look for a donor movement as a replacement or for parts needed.
 

shutterbug

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You also have the option of shipping the movement to someone for repair and then putting it back in the case yourself. But I recall you said you were a mechanical engineer. If you really want to tackle this one yourself, get some books on basic clock repair and do some digging into how they work and what needs to be done to repair them. There are also some good online sites that teach basic repairs visually. One I like is Tascione.
Whatever you decide to do, we're glad you checked out our site. Let us know what you decide to do. Clock movements are only scary to look at. They are are wondrous things when you understand them :D
 
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