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Chronotachymetre Servicing


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I found a rather elegant chronograph pocket watch on the bay recently. It was listed as non-running so I took a punt on it. Not cheap, but I liked the dial. The watch wouldn't run if the chrono was engaged, and would barely run without it. It's a French watch made by LIP.

 

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Popped the moment out of the case to have a look. It's very pretty in there...

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Time to strip it down. Took many photos so I could put it back together in the right sequence. Here's a bird's eye view of the chronograph works

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Removed the operating lever, pillar wheel, transmission wheel and various springs

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Removed the chronograph bridge:

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And the movement's now just a plain ol' pocketwatch movement:

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Time to see what's wrong with the movement itself:

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...and found the culprit, or at least a suspect! Cracked 3rd wheel jewel:

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Spent a quiet Sunday morning sifting through my box of random jewels until I found one with the right diameter for the pivot:

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Reamed a wider hole and fitted the new jewel. I was pleased the colour matched the old one:

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Now I can put the movement back together. With the new jewel and a lot of cleaning the watch works extremely well - one or two seconds fast and only a little beat error which I'm going to ignore. Putting the chrono works back together was relatively straightforward - just a matter of lubrication and adjusting the eccentrics so that the depthing was correct:

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Time to fit the hands. The second hand for the chrono wasn't tight enough on the arbor, so every time you re-set to 0 the hand would spin! Tightened it with a cannon pinion tightener - there must be a better way!

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Movement goes back in the case:

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And another fine watch for my collection of slightly-battered-but-working-well watches. This was the first chronograph I've done, so I'm extremely pleased that it's working nicely. Learned a lot in the process. One of the things I learned was not to use Naptha on dials. The astute observer will notice that the word LIP has vanished from the dial. While I feel extremely guilty for having done this to a 100-year old watch, I'm secretly delighted - the first thing my wife said when the watch arrived in the post was "lovely dial, pity it says LIP on it...", and I agreed.

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Thanks for watching. 

 

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Time to fit the hands. The second hand for the chrono wasn't tight enough on the arbor, so every time you re-set to 0 the hand would spin! Tightened it with a cannon pinion tightener - there must be a better way!

I do it this way - it often works.

post-374-0-39851600-1426577755_thumb.jpg

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  • 4 weeks later...

Brilliant job - well done. And I really love that watch - it's a cracker.

 

Regarding the hands, I can never be bothered with doing it with a lathe collet - the pin vice is always to hand and a lot less messing around.

But you might argue that a lathe collet would compress more evenly across the length of the tube than a pin vice.

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Brilliant job - well done. And I really love that watch - it's a cracker.

 

Regarding the hands, I can never be bothered with doing it with a lathe collet - the pin vice is always to hand and a lot less messing around.

But you might argue that a lathe collet would compress more evenly across the length of the tube than a pin vice.

 

Here is yet another way of tightening a second hand that is only a little loose - with digital output!

Somewhat like canon pinion tightening.

 

post-374-0-53516800-1429441825_thumb.jpg

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I like your thinking Colin!

Another great use for digital calipers is removing splinters from your skin. They grip a lot better than tweezers and even let you know what size the skelf is! :)

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Both new uses of caliper noted for further use! I can combine them when a splinter gets in a watch's hand... aaaah! Just me and one of those moments!  :)

 

Great thinking guys!

 

@Colin: Good to see you around, Colin and as always with great input! Cheers!

 

Cheers,

 

Bob

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Geo that last suggestion is hilarious. I just had an image of me trying to pull out splinter from my foot with a digital caliper--

JC

I wasn't joking Joe, they are brilliant for that. Working in engineering I was forever getting tiny slithers of metal in my fingers, and the callipers always worked when tweezers failed!
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Excellent wakthrough and job!!!

Congratulations!!!

Another way to evenly tighten a hand tube, is by using the appropriate size of a punch stake in your staking set. Just find the one that nearly fits the tube diameter and push the punch lightly onto the hand (no hammer needed just a finger push from the top).

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