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Incabloc Lyre Spring Replacement - Help Please

Deggsie

By Deggsie
in Watch Repairs Help & Advice

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Deggsie WRT Addict

Deggsie

Posted
Posted

Hello all.   

Whilst servicing a Favre Leuba Sea King with Twin Power FL253 mov't. I managed to break the incabloc lyre spring during chaton/stone removal.  Presumably the spring material had become brittle over the years, or maybe I wasn't as gentle as I needed to be? Probably the latter! 

I know the part number for the replacement lyre spring, and these are fortunately still stocked by Cousins UK, so no problems there.  What I would like please is some advice on the procedure for pressing the bloc from the main plate so that I can a) replace the dead lyre spring and b) reverse the process, ensuring that the bloc is returned to its exact original position.  I say the exact original position, because prior to my faux par the balance end shake was perfect and the balance oscillated beautifully with little friction. 

Will I need the dedicated incabloc tools, maybe a jeweling press, or can the operation be carried out carefully with a staking set?   I've been very lucky so far, and never broken a lyre spring - so this is a first time replacement for me.

Thanks in advance for your advice.

Nucejoe Distinguished Member

Nucejoe

Posted
Posted

Hi D, To remove, I push on the jewel housing from outside inward the Ebauche.
Reinsert is from inside ebauche, with shock spring locked, ( empty of the jewels).
I approach the desired repositioning ( for decent end shake) in small increments as I know of no tool that would drive the jewel in by calibrated micrometer action.
I hope this helps.

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clockboy Distinguished Member

clockboy

Posted
Posted

If it is just the shock spring that needs replacing then there is no need to remove the bloc. If you do need to remove the block then it is important that you note its height position. A little height difference makes a huge difference to its performance.  

Fitting a new spring is tricky but here are my tips (learn't from many hours of mishaps):

1. Really good magnification (I use a microscope)

2. De magnetise the spring and tweezers

3. Cover the block with clingfilm , which I used to do as they like to fly, therefore purchase more than one

4. I fit with very fine dressed tweezers and steady with fine peg wood 

5. Do not force anything as the springs can easily go out of shape

6. A absolute clear and clutter free work area.

 

Deggsie WRT Addict

Deggsie

Posted
  • Author
Posted

Thanks for your reply Clockboy, I think with the type of Incabloc I have, the only way to install the new lyre is to expose the entrance to the hinge, which I believe to be on the outside diameter of the bloc, therefore it’s essential to drive the bloc at least partially out (maybe all the way). I tried taking out the existing lure but can see no way without removing the bloc.

Nucejoe. Thanks for your reply too. Can I ask a dumb question please? I have seen the word Ebauche on many occasions but what dose it mean? Is it a Swiss term for the overall movement? Exploring your answer more, do I really need to fully remove the bloc from the main plate? I’m hoping to get away with say 50 %, enough to expose the hinge slot. Also, can I do this with a staking press, jeweling press or do I need the Incabloc stumps? Aggghhh. These tiny things are sent to test us! [emoji846]

Enjoy your Sunday


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Deggsie WRT Addict

Deggsie

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  • Author
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Hello Clockboy. Oh, I wished the Incabloc I have was that simple to service! That is a beaut! Unfortunately the hinge on my lyre spring is captive until the bloc is pressed out either partially (I hope) or in full (please not) from it’s locating bore. I’ll try to find a good photo showing the predicament I’m in. It may turn out to be a simple job when all is said and done.

Kind regards Deggsie


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watchweasol Distinguished Member

watchweasol

Posted
Posted

Hi Dreggsie  Mark who is the site administrator, and who produces some excellent instructional videos has one on the very subject so I suggest you find it out and have a look. A picture or in this case is worth a thousand words.  It will be worth your time.

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Deggsie WRT Addict

Deggsie

Posted
  • Author
Posted
Hi Dreggsie  Mark who is the site administrator, and who produces some excellent instructional videos has one on the very subject so I suggest you find it out and have a look. A picture or in this case is worth a thousand words.  It will be worth your time.

Thanks watchweepole. I’ve looked for that video but no luck. If you have a link, it would be much appreciated my friend


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