Landeron 51 Question.

JimInOz
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I'm currently servicing a Sully Watch Chronographe Suisse for a mate.
When I get the bare movement I usually like to remove the balance before breaking down the rest of the movement.
However!
The balance cock screw is much (much) tighter than I have experienced with similar size screw and I'm reluctant to get gorilla with it.

Any tips on making this screw come out without breaking the head off?

@sheepdoll , @Archer and any other gurus?

L51Balance.JPG
 
Archer
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You could apply some penetrating oil and let it sit.

Sometimes lightly tapping on the screwdriver when it's in the slot will help, or tightening the screw slightly before loosening...
 
Canuck
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Or, if flipping the movement face up with the dial off, you expose the bottom tip of the screw, put a drop of oil on the tip of the screw and let the movement sit dial side up over night. Be very careful “tapping” the screw, or you might take out the balance staff!
 
Archer
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Canuck Canuck
Be very careful “tapping” the screw, or you might take out the balance staff!

I'll give Jim more credit than you do - you would have to try pretty hard to break a staff by lightly tapping on the screwdriver while it's in the slot...
 
Canuck
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Archer Archer
I'll give Jim more credit than you do - you would have to try pretty hard to break a staff by lightly tapping on the screwdriver while it's in the slot...

Oh, really?
 
Archer
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Canuck Canuck
Oh, really?

Yes, really. Unless you are terribly uncoordinated, there's not a lot of risk...
 
Canuck
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Archer Archer
Yes, really. Unless you are terribly uncoordinated, there's not a lot of risk...

Oh, really?
 
Archer
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Canuck Canuck
Oh, really?

Please stop being a troll...
 
JimInOz
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Thanks gents, I'll give the penetrant oil and light tapping a try.

Don't worry Doug, I won't use a hammer, just the end of my tweezers (lightly).
 
sheepdoll
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I'd go with what @Archer reccomends. Penitrating oil and time.

I never was able to get the Bergeon screw extractor to work. The screws are too hard for the pins to hold them without slippage.

The landerons lend themselves to being stripped down from any direction. Remove the chrono first. Then the winding bridge. (Remembering to let off tension.) I often find that I like to assemble the balance and pallet first so I can see the beat alignment. It is not uncommon to take these down multiple times.

The one thing to watch out for is that pesky hairspring.

The hardest part is the waiting.

Edit: The Balance cock screw is longer than the other plate screws. Although if others have worked on the watch I sometimes find it swapped with the chrono bridge screw (which can mess things up.)
Edited:
 
JimInOz
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Thanks for all of the tips folks.
After a drop of WD40 Pentrant on either end of the screw and a 24 hours soak time, followed by a gentle tap or two with the head of my tweezers on one of my cheap screwdrivers, the balance cock screw only took the lightest of twists to undo.

Balance out allowed my to remove the pallet cock and pallet, and then the barrel bridge and the stuff under it.

And then I met my little friend again 🤬.
The chrono driving wheel.

ChronDriverWheel.jpg


This must be removed to allow the train bridge and wheels to be taken out. I think I did the last one with modified hand levers, but this one is too close to the bridge to do that, so I'm waiting for a five spoke Presto puller (probably the last one in the country) to arrive tomorrow, then I can get back to work.
 
Canuck
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Last time I checked, Perrin in Toronto had the Presto wheel puller in stock.
 
JimInOz
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Canuck Canuck
Last time I checked, Perrin in Toronto had the Presto wheel puller in stock.


AU_CA.png






😉
 
Canuck
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JimInOz JimInOz
AU_CA.png






😉

Distance a problem? I have an Omega date ring that came from Mannheim, Germany, an Omega watch case from Madrid, Spain, and a Zenith pallet from South America! Glad you found a puller. Good tool!
 
JimInOz
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Canuck Canuck
Distance a problem? I have an Omega date ring that came from Mannheim, Germany, an Omega watch case from Madrid, Spain, and a Zenith pallet from South America! Glad you found a puller. Good tool!
Distance isn't a problem, I've had to purchase stuff from all over the world including Canada (Perrins, McCaws) as we don't have big supply houses here.
However, I've been looking for one of these for a while and when one popped last week up at my local supplier (only 1,800 kilometres away) I grabbed it.

Lucky I did.

Screenshot 2023-05-04 at 23.13.54.png
 
C
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Very good tool to have, over the years I have seen so many of those pivots bent, and the wheels damaged. I will not even talk about the jewels.
 
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