Mainspring Advice

Vint

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Oct 14, 2020
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I have a Gustav Becker wall clock probably late 1800’s and both the strike and time mainsprings are “set”. They measure 3/4” x 0.23 x 47” long. Due to the clock’s age I don’t want to install the same spring strength for fear that the springs will have an adverse affect on the trains overall.
Can someone give me a recommendation as to a particular size that will suffice in this particular situation? Thank you.
 

Willie X

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Feb 9, 2008
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Your old springs are probably fine.

Look up "Willie's Turns of Power".

In short, you calculate how many turns the barrel makes in a week. Then you count how many turns of power your spring will actually provide. If you have more turns available than you need for a week's run, everything is hunkie-dorey with the spring. You can look for the problem elsewhere.

Wear at the pivots is the most likely culprit, followed by damaged or deformed parts, and finally the escapement.

Willie X
 
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R. Croswell

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I have a Gustav Becker wall clock probably late 1800’s and both the strike and time mainsprings are “set”. They measure 3/4” x 0.23 x 47” long. Due to the clock’s age I don’t want to install the same spring strength for fear that the springs will have an adverse affect on the trains overall.
Can someone give me a recommendation as to a particular size that will suffice in this particular situation? Thank you.
May I ask why you feel the springs are "set"? I'm not sure what size spring this clock is supposed to have but 0.23 cannot possibly be the correct thickness unless you are measuring in mm. I would not be be too concerned with the clock's age, brass and steel do not become weak over time. If there are worn or damaged parts these of course should be addressed. Unless the original springs have been replaced with the wrong size, the original size should be fine. '

RC
 

Vint

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May I ask why you feel the springs are "set"? I'm not sure what size spring this clock is supposed to have but 0.23 cannot possibly be the correct thickness unless you are measuring in mm. I would not be be too concerned with the clock's age, brass and steel do not become weak over time. If there are worn or damaged parts these of course should be addressed. Unless the original springs have been replaced with the wrong size, the original size should be fine. '

RC
May I ask why you feel the springs are "set"? I'm not sure what size spring this clock is supposed to have but 0.23 cannot possibly be the correct thickness unless you are measuring in mm. I would not be be too concerned with the clock's age, brass and steel do not become weak over time. If there are worn or damaged parts these of course should be addressed. Unless the original springs have been replaced with the wrong size, the original size should be fine. '

RC
When I removed the two springs they didn’t seem to be tightly coiled in the barrel and seem to have very little expansion. They are the hole type and I didn’t see any cracks or tears on the spring and overall look good. Yes I measured the thickness in mm several times to make sure I was getting the correct reading. I use a digital micrometer. My late father-in-law brought this clock back from Germany in 1965 hoping to someday repair but unfortunately it sat in a cardboard box outside in a shed in Florida until 2020 when I asked to have it.
 

Vint

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Your old springs are probably fine.

Look up "Willie's Turns of Power".

In short, you calculate how many turns the barrel makes in a week. Then you count how many turns of power your spring will actually provide. If you have more turns available than you need for a week's run, everything is hunkie-dorey with the spring. You can look for the problem elsewhere.

Wear at the pivots is the most likely culprit, followed by damaged or deformed parts, and finally the escapement.

Willie X
The movement is encrusted with dirt and grease and has been in the clock non working since before 1965 to my knowledge. Upon disassembly of the movement after cleaning it in ultra sonic I didn’t see any obvious damage other than a few bent pins on a wheel or two. Today I’ll be taking a closer look, pegging, polishing,etc. The escape wheel teeth are sharp as ever and I didn’t see any worn pivots needing attention.
With regard to the main springs they both came out of the barrel way too easy and although in good condition I assumed they would need replacement…..
 

tracerjack

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Better to see if the clock works properly with the springs you found in the barrels. As Willie X has often posted, "set" springs will still power the clock properly, they just won't last the expected days of run. Once you know the springs will properly run the clock, then you will have a better idea of size if you decide to get new ones. Working with 400 day clocks, I often find springs that have set in the barrel for so long, they don't show much liveliness when removed. Yet, once cleaned, they do the job perfectly.
 

Vint

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Better to see if the clock works properly with the springs you found in the barrels. As Willie X has often posted, "set" springs will still power the clock properly, they just won't last the expected days of run. Once you know the springs will properly run the clock, then you will have a better idea of size if you decide to get new ones. Working with 400 day clocks, I often find springs that have set in the barrel for so long, they don't show much liveliness when removed. Yet, once cleaned, they do the job perfectly.
Good to know and I will do just that. Thank you.
 

Allan Wolff

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Most of the German movements from this period typically run 12+ days on a full wind. Even if the springs are set or tired, you should be able to get 8 days from a freshly cleaned and oiled movement without much trouble.
 

Vint

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Most of the German movements from this period typically run 12+ days on a full wind. Even if the springs are set or tired, you should be able to get 8 days from a freshly cleaned and oiled movement without much trouble.
Thanks Allan. 8 days are good for me. I’m in the process of putting the mainsprings back in operation.
 

R. Croswell

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0.23mm thick springs are only 0.009" thick which is a very thin mainspring for an 8-day clock so it is not surprising that it came out of the barrel easily and didn't feel like it had much strength. As has been said, and 8-day clock typically will run a little longer than 8-days. If you clock just runs 8-days and no longer then it will likely begin to stop after 7-days and perhaps 6-days at some point down the road. It isn't always easy to know if there is a mechanical problem in the movement or an issue with the mainspring. It is easy to blame the mainspring. If this clock runs for 8+ days after being cleaned the spring is probably healthy, if it runs just 8 days or less there is likely still a problem that will eventually get worse. Maybe the mainspring, then maybe no.

RC
 

Vint

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0.23mm thick springs are only 0.009" thick which is a very thin mainspring for an 8-day clock so it is not surprising that it came out of the barrel easily and didn't feel like it had much strength. As has been said, and 8-day clock typically will run a little longer than 8-days. If you clock just runs 8-days and no longer then it will likely begin to stop after 7-days and perhaps 6-days at some point down the road. It isn't always easy to know if there is a mechanical problem in the movement or an issue with the mainspring. It is easy to blame the mainspring. If this clock runs for 8+ days after being cleaned the spring is probably healthy, if it runs just 8 days or less there is likely still a problem that will eventually get worse. Maybe the mainspring, then maybe no.

RC
Thanks RC for this info….it helps.
 

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