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Hebdomas Bridge Repair

jdrichard
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jdrichard Distinguished Member

jdrichard

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So I needed to remove a broken screw from the bridge, the one that locks in the Hairspring stud. I first tried drilling it out with small bits from China and this resulted in a peek in the hole. Then I got a great idea and took a bit that broke and filed it down to a wedge,like a screwdriver bit. This got rid in the peek and allowed me to use another bit with cutting oil. And it worked. Used a lathe for this with a collet holding tail stock.

 

Here are are the pictures.

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jdrichard Distinguished Member

jdrichard

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Nice work and good example of how a faceplate can save the day! I do faceplate work all the the time much to the perplexment and eventually enlightenment of apprentices around here.

After all that work, it was still the wrong spring strength. Not sure how to get the right spring for this watch. Should I add weight to the balance?

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jdrichard Distinguished Member

jdrichard

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How fast is it running?

Really fast. First, I use e-timer and not sure it can read the frequency, bph. I is only swinging about 90 deg. I really need to figure out the strength of the hairspring I need. Got it working however.

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Nucejoe Distinguished Member

Nucejoe

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Hi J, Hi Nickelsilver,       JD ,  Have you tried to supply power to the barrel manully, to a normal level ?  Not only tells about MS, it further gives you some idea to judge the escape on.

I suspect the pallets for inadequate or improper impulse supply.

Isn,t the advantage of breguet HS that it lets increase in active length of H not limited by regulator pin? I think you got enough space there to increase the HS  length up to 15 mm, therefore no need to know the exact HS strength.

 

 

 

 

 

 

 

 

 

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jdrichard Distinguished Member

jdrichard

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Hi J, Hi Nickelsilver,       JD ,  Have you tried to supply power to the barrel manully, to a normal level ?  Not only tells about MS, it further gives you some idea to judge the escape on.
I suspect the pallets for inadequate or improper impulse supply.
Isn,t the advantage of breguet HS that it lets increase in active length of H not limited by regulator pin? I think you got enough space there to increase the HS  length up to 15 mm, therefore no need to know the exact HS strength.
 
 
 
 
 
 
 
 
 

The hairspring actually stops at the stud, so no way of getting additional hairspring length.


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Nucejoe Distinguished Member

Nucejoe

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6 hours ago, jdrichard said:


The hairspring actually stops at the stud, so no way of getting additional hairspring length.


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If it came down to replacing with a longer HS. The regulator pin dose not limit the length of breguet HS, as it dose with ordinary HS coil.

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Nucejoe Distinguished Member

Nucejoe

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3 hours ago, Nucejoe said:

If it came down to replacing with a longer HS. The regulator pin dose not limit the length of breguet HS, as it dose with ordinary HS coil.

Oce sure a new HS is the only option, I would try resonating a plain HS to get the right frequency, leave some extra length on.The overcoil is not as much pain as it is made out to sound. The old HS shows all the right length and bends, it is a model for sculpture. A good parts of the over coil shaping should be done inside the movement, you van see how much to raise and bend to get to impulse pin, end length curve is about the same and is to be done before the raise.

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Nucejoe Distinguished Member

Nucejoe

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So the watch ifself is our living datasheet. Before getting to this, I must repaeat I agree with Nickelsilver.

On 4/2/2019 at 2:06 PM, nickelsilver said:

You'll want to get the amplitude up before going any further on the timing. With only 90 degrees there must be some serious issues.

I agree with Nickelsilver. 

Once it came down to replacing the HS. The watch itself is a living datasheet.

No problem to fly a new HS with this BW, inside the watch.

Regards

 

 

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