# Refitting mainspring



## Phil C (Nov 26, 2018)

Raw novice here again. Having taken apart an old movement I was given (in order to get a bit of practice), I have now started to try to put it back together again. Please see photos attached. Any advice please on how to refit the mainspring? Phil.


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## simon2 (Dec 5, 2010)

The mainspring you are using has very little life in it. ( We use the term, SET). In order for the clock to run for a full 24 hours the mainspring will need to be replaced.

The outer cylinder of the case has to be removed. So that a fresh, stronger, mainspring can be wound onto the great-wheel arbor. When the movement is fully assembled. I will explain, how. When you have a new mainspring. Hope this helps.


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## Phil C (Nov 26, 2018)

Thanks, simon2. More questions: 1. How can you tell it's set (so that I'll know in future)? 2. How much do you reckon a new mainspring will cost (I guess the clock is pretty worthless?)? 3. When I come to wind a spring on, do I need special equipment, eg a winder? Phil.


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## simon2 (Dec 5, 2010)

Q1. A new mainspring for that clock, would look more like a straight ribbon of spring steel. Depending on the "New Mainsprings", actual age. As most are wound into a holding device for ease of storage. ( in the old days the "C" ring retainer was called a "Yuk"). A good useable mainspring, for that clock. Should have a "At Rest" diameter at least equal to the diameter of the movement.

Q2 A new Mainspring is available from Cousins. For approx £3 to £4

measure the width of the old spring and also it thickness. The type of mainspring you require is known as a " loose Loop" mainspring. If to have trouble getting a spring. Give me the sizes and I will get it for you

Q3 as for winding the new spring into the clock. All you will need is your hands and a good fitting winding key. No other tools should be required. You will need to remove the movement from that side casing. So you can fit the new spring when the movement is completely assembled.

hope this helps. Regards Simon.


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## Phil C (Nov 26, 2018)

Thanks very much for this, Simon. I'm afraid I don't have a winding key - please see my other post, entitled "Winding Mechanism". Phil.


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## vinn (Jun 14, 2015)

Phil C said:


> Thanks, simon2. More questions: 1. How can you tell it's set (so that I'll know in future)? 2. How much do you reckon a new mainspring will cost (I guess the clock is pretty worthless?)? 3. When I come to wind a spring on, do I need special equipment, eg a winder? Phil.


 for clocks, you will need a winder. for watches, I use my thumbs. vin


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## Phil C (Nov 26, 2018)

I'm not surprised. I've given up trying to fit this one by hand. There is no drum for it to fit in, and it's a bit like trying to herd cats (is that the expression?). Anyway, as Simon says above, the existing spring is no good. The reason I ask if I'll need a winder, if and when I get a new spring, is that I think winders might be quite expensive? As I say, the clock, I believe, is worth nothing, other than as a learning device for me. Also, would a winder work when there's no drum? It's just one question after another, isn't it?! If I'm asking too many, somebody please tell me - I won't be offended. Phil.


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## simon2 (Dec 5, 2010)

If I can. I will always answer all questions. As for your " loose Loop" mainspring,there is no tool to wind it into the clock. It's easy to do. I will explain, perhaps via the Telephone, when your ready.

To hand fit a mainspring into a mainspring Barrel, by hand, can be fiddly, but is possible. Even up to Fusee size.


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## Phil C (Nov 26, 2018)

Okay, thanks, I'll look to get a mainspring. Measuring it, I get about 7.5mm wide and about 0.25mm thick. One I see is on the Cousins website is 7.5 x 2.5 x 750 mm, but that seems awfully long?

Also, as you can see from the photos above, there is no barrel for the spring to wind into. Is that okay?

By the way, regarding a winding key, have you seen my posting "Winding Mechanism"?

Phil.


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