Refreshing Old Springs

Kieran McCarthy

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Is it possible to "refresh" old or tired main springs by winding them as tightly as possible on an arbour, retaining them in that position with a clip, and temper them?
Thank you. Kieran
 

shutterbug

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I can't recall anyone ever trying it - but they make them by probably using that procedure. Even heating and quenching and annealing back would be critical components of the process.
As a side note though, I've never found a mainspring too weak to run a clock for a week. If they aren't broken, I reuse them. The modern springs from India are just not worth buying.
 

glenhead

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Umm, yes, it would be possible, but...

First off, you wouldn't want to do this with the spring wound tightly. The purpose of the spring is to UNwind and deliver power to the train. You'd have to do the heat treatment with the spring relaxed. If it's set you'll want to work it to relax it more than where it is. (Yeah, that's vague.)

You have multiple challenges here. One of the biggest ones is that there's no way to tell the structural condition of the spring's steel. Are there weak spots? Cracks? A spring is subjected to all sorts of stresses as it does its job. It wants to be in its relaxed shape. Deforming it from its relaxed shape causes stress, and the spring makes things run by striving to get back to its relaxed shape.

If you decide to try to refresh it, it'll be a multi-step process. I'm not going to go into detail on each of the steps - if you want to try it, there are dozens of places to find the process for each step. The biggest challenge is going to be consistency. You'll pretty much have to have a heat-treating oven or a kiln, and your quench technique will need to be spot-on. The spring has to be heat treated as a unit; that is, the changes to the spring have to happen at the same time. Failure to do that will cause areas of the spring to have different characteristics, and that can cause failure. First you'll want to normalize the steel by running it through several annealing cycles. That'll make the grain structure as consistent as possible. Then you'll harden it. That's the process that has the highest probability of being inconsistent unless you build some sort of jig or something to hold the spring and allow you to quench it as a unit. The steel must be quenched as flat as possible, again to achieve consistency in the grain structure. Then you'll want to temper it to blue.

Again, possible? Yes. Something I'd want to try? Perhaps, just to experiment with. Would I put such a spring in a clock the first time I tried it? Not a chance, not if I liked the clock. :) Tenth time? Depends on how well the first nine went.

I hope this helps.

Glen
 
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R. Croswell

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Is it possible to "refresh" old or tired main springs by winding them as tightly as possible on an arbour, retaining them in that position with a clip, and temper them?
Thank you. Kieran
The answer is no, winding the spring tightly and retaining it in that position for a period of time will, if anything, have the opposite effect. If the spring is unwound and stretched out, as is sometimes done when cleaning the spring it may be "refreshed" so that its relaxed uncoiled diameter is greater allowing it to act invigorated. Unfortunately, my experience suggests that the effect is relatively short lived. Stretching out a main spring as a means to solve a "power issue" is not advised. A "weak" main spring is seldom the reason for a clock not running.

RC
 

Willie X

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Question, what make you think the spring is weak?

Most American clocks require about 7 turns of the mainspring to run a week and European clocks require about 3 or 4 turns. Just about any ole spring will provide more than that. A well serviced old spring will provide close to two times that? In short, your problem is elsewhere.

It will be impossible for you to "refresh" your spring with heat treatment. Even the companies that make springs have a hard time getting it right.

Do you know how to properly service a spring? You have to remove it from the clock, stretch it out and clean it up good. Then treat it to a thin even coat of high quality oil. Willie X
 

Mike Phelan

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That's exactly what I've always done, Willie. Some larger springs like chiming springs on Napoleons I use turret clock oil or even grease.

Many will recoil in horror when I've also told them when I stretch the spring out fully and reverse it before putting it back in the barrel. It's always worked OK for me. :eek:

Newer springs aren't as good as the originals in most cases.
 

Thomas Sanguigni

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Mike Phelan said: Many will recoil in horror when I've also told them when I stretch the spring out fully and reverse it before putting it back in the barrel. It's always worked OK for me.

Could you explain how you go about reversing the spring?
 

R. Croswell

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Many will recoil in horror when I've also told them when I stretch the spring out fully and reverse it before putting it back in the barrel. It's always worked OK for me. :eek:
At your own risk. Have you ever tried to brake off something like a can lid by bending it back and forth? The first couple of bends seem to have little effect but eventually the metal of the lid, after repeatedly yielding to the bending force, becomes fatigued and snaps off. I'm not recoiling in horror at something that you find works for you, but I believe the method you describe - deforming the spring past the yield point is subjecting it to unnecessary stress which could potentially lead to premature failure, especially if the procedure is repeated on the same clock every few years as part of routine maintenance.

It is interesting to note that the German Timebomb clocks (Google the term) were designed to wind the mainspring from one spool onto another in the opposite direction. Perhaps that's one of the reasons they fail violently and were removed from the market.

RC
 

Willie X

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Huckabee, one of the great clock repair writers, recommended "reversing" the springs. On his recommendation, I tried it quote a few times with mixed results. My failure rate was about 50% and it's very difficult to do this. Also, this was back in my early years when I too thought the springs were often the cause of a non running clock. Now I know different. My failure rate on reholing the inner coil stands at around 50% also. Those inner coils do not like to be messed with! Willie X
 
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roughbarked

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At your own risk. Have you ever tried to brake off something like a can lid by bending it back and forth? The first couple of bends seem to have little effect but eventually the metal of the lid, after repeatedly yielding to the bending force, becomes fatigued and snaps off. I'm not recoiling in horror at something that you find works for you, but I believe the method you describe - deforming the spring past the yield point is subjecting it to unnecessary stress which could potentially lead to premature failure, especially if the procedure is repeated on the same clock every few years as part of routine maintenance.

It is interesting to note that the German Timebomb clocks (Google the term) were designed to wind the mainspring from one spool onto another in the opposite direction. Perhaps that's one of the reasons they fail violently and were removed from the market.

RC
The words are; metal fatigue.
 

Kieran McCarthy

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Is it possible to "refresh" old or tired main springs by winding them as tightly as possible on an arbour, retaining them in that position with a clip, and temper them?
Thank you. Kieran
Firstly, thank you to all who contributed. I have learned from the thread and I will not be ever trying to "refresh" an old spring.
Secondly, what a Dumbo I am. I will never post a thread first thing in the morning again without proper deliberation. What was I thinking about winding the spring tightly, heating it, and trying to temper, doing the exact opposite of what would be logical? And I an Engineer, albeit a Polymer Engineer though metallurgy was a significant element of the curriculum. Duh.

Relatively new to Horology, I have experience on just about 25 clocks to date, though my skill set is improving fast. I simply presumed that on clocks 50 years + it was a good idea to fit new springs when cleaning, servicing, repairing. Some of your comments suggest that may not be necessary.

I recently acquired a small Junghans mantle clock, (62 mm dia face), as per the photograph but it only runs for 22 hours on a winding so I assumed it is a one-day clock in need of a new spring and servicing. I tried to source an exact spring online but failed to find one, so the "refresh" idea came to me, obviously now in a bad dream. Might a good cleaning and service be all that is required to get it to run for the 24 + hour period? Indeed if a new spring is required, I can always go for as near as possible replacement. Regards, Kieran

Junghans Mantle Clock.jpg
 

shutterbug

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Yep. You probably have worn pivot holes that will need to be bushed. Wear causes friction, and when it becomes too much for the spring to "power through" the extra burden, it gives up. Fix the wear and the spring will happily supply enough power to run the clock again.
 

SuffolkM

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On the subject of servicing springs, I often do this (see photos) with large springs. Basically turning the spring onto its own outer diameter. It opens the inner spring turns more than normal, but without trying to make them straight (and keeps the amount of energy down during cleaning too - you don't have the entire spring ready to pop in your hand this way).

184DDACA-72E5-401D-B5DE-66C6196EB7B8.jpeg 8D24EC91-1C87-4DEE-871D-4D39F1CC4A14.jpeg
 

Willie X

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That's kind of a natural way to do it. But try stretching out that part (between the coils) about 2 feet at a time. This gives you some working room. I've never had a spring that was in any way damaged by stretching it out flat. Leave the innermost (several coils) alone; they add very little to the power equation anyway. Willie X
 

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