# Fusee watch service



## Sir Alan (Sep 10, 2010)

I've spent the last 6 weeks or so learning how a Fusee pocket watch works. This little adventure started with a work colleague bringing in three watches that he had recently inherited from his two grandfathers. Two were wrist watches (one a beautiful gold watch presented for 50 years of service) and the third a silver cased pocket watch.

He asked me to take a look at all three, noting that the pocket watch wasn't working. Once I'd figured out how to get into the pocket watch (and it wasn't obvious) I realised that I had a Fusee movement.

My first reaction was to put the movement back into the case and move on, but partly because I do love a challenge, partly because I figured I couldn't make it any worse, and partly because another enthusiast had mentioned to me that he had recently come into possession of one of these I thought "why not?" and set about discovering how these things tick (or actually why it wasn't).

Here are some photos of what I was greeted with when I worked out how to get the back cover off the movement







yikes!!

The fusee chain is a thing of engineering beauty



It took me quite a while before I decided to "go for it" and strip the movement down - most of my hesitation was around the fusee and not knowing how it worked or how to unwind it.

At this point I had to remove the dial - which is held in place by 3 pins, pushed through hole in the dial feet - this is the same as the back plate. You can see one of these pins in the next photo



getting these out without breaking them was fiddly. Taking the dial off revealed this



then I flipped the movement back over to remove the balance/hairspring

This presented another challenge. On all the 'modern' watches I've worked on, the hairspring is attached to the balance cock, so removing the balance cock allows the balance/hairspring to be lifted off as a single assembly. Not so on this movement.



the above picture is with the balance cock removed, and you can see the hairspring held in place to the bridge plate by another of those fiddly pins.

Removing the pin allowed me to carefully slide the hairspring out of the holding stud, and through the regulator arm. Then I removed the four pins holding the bridge plate on and lifted it off



the escape wheel stayed in place (held by the congealed oil) and I got my first proper look at the movement



Nice. And simple.

Then I set about cleaning all the parts









and when clean, I set about getting it all back together.

Now in principle, and with the wisdom of hindsight etc. the rebuild is actually very simple. There are after all only a few components (compared to some of the modern chronographs I work on).

However, it took me about 7 iterations to get the watch correctly assembled and diagnose what the fundamental reason for it not running was.

Having finally realised how the fusee chain should be wound (round about rebuild number 4 I think) and on rebuild number 6 learning that there needs to be some pre tension applied (via the mainspring) and still having a watch that I couldn't wind (and so wouldn't run) I inspected the mainspring barrel to find this



The mainspring should be attached to the central arbor and it wasn't - in fact it was not only unattached but bent out of shape.

At this point I decided to try to re-form the spring, bending it so that it would catch on the arbor. This was fiddly because I didn't want to remove the spring from the barrel - I felt this was too risky (the risk being that I might not be able to get it back in).

After about 15 minutes of fettling with my smalled pliers I achieved this



which was enough.

So I set about rebuild number 7







these pictures showing how the chain should be wound.

And ...... I was able to wind the watch (the smoothness as the chain is wound off the barrel and onto the fusee cone is beautiful) and the watch ran. And kept running.

So I completed the rebuild, fitted a new crystal and here it is





the hallmarks date it to 1885.

My colleague is going to show his mother. It was her fathers watch.


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## davidcxn (Nov 4, 2010)

Fascinating post & great pictures. :thumbsup:

Well done giving a 132 year watch a new lease of life. :yes:


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## gimli (Mar 24, 2016)

Good job and thank you for the pictures and words!


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## Karrusel (Aug 13, 2016)

Excellent post Sir, perhaps we can all appreciate why watchmakers employed the services of young girls to assemble the fusee chains (small fingers).

:thumbsup:


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## dobra (Aug 20, 2009)

Interesting exposition and thanks for ssharting it.

mike


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## harryblakes7 (Oct 1, 2010)

Well done!!

You were very lucky that the mainspring was broken, as taking it apart without removing the pre-load it would have rapidly thrown its inner workings three meters in every direction! :laugh:


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## Rastko (May 8, 2017)

Hi, Thank you for a very insightful photo guide. At the moment I have a couple of fusee watch in my drawer that I am somehow still hesitating to open. But I may soon give it a try.


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