Help with balance wheel of Landeron 48 movement

[GeorgeClarkson]

I am in the process of servicing the Landeron 48 movement that came with the complete watch with wrong dial applied, as many of you can recall from my other thread. After a brief check I noticed something was wrong with the balace wheel, so after inspection of the part, I discovered that the upper pivot was broken.

I had another balance wheel with bent hairspring, so I decided to replace the balance wheel using the original hairpring. After a bit of tinckering, I managed to do just so, but a new problem arised, which will be shown in the linked videos here below.

The first video shows how the new balance wheel turns freely after a bit of adjustment in the movement:

The second video shows the problem I faced after replacing the hairspring onto the balance wheel and reassembling everything back together. Basically, the amplitude is extremely low, but I cannot figure out still what can be the problem.

The second video above shows the issue better than a thousand words...

I need the help of the experts, here: what can the issue be? I followed all Mark's videos on putting the watch in beat, checking the pivots, pallet stones, everything. I have never seen such behaviour before. What can it be?

[matabog]

talking about the second video:  in the first half the balance pivot is not set right in the upper jewels; in the second half it apears to be overbanked - meaning the impulse pin is on the wrong side of the pallet fork horns.

...just thinking out loud...

[clockboy]

Normally it,s the replacement balance staff a touch to long. What mark does when he replaces a staff he re-assembles without the hairspring attached & checks the end-shake. If it is a touch tight it will need honing down a bit.

To test put a piece of paper under the balance bridge to see if it improves.

 

I see that you found the bridge was a touch bent causing the tightness. But as you say if bending to much the the upper & lower jewels will not be aligned.

[szbalogh]

I have the feeling that the problem is what Metabog also suggested. You have to insert the balance on the right position to avoid this problem. Check Mark's videos! He is turning the balancecock while inserting it in place. 

I see on the first video that the balance is actually not true and has to much sideshake! 

To check the endshake: Disassemble the train and leave only the balance in place. Then turn the movement sideways near to your ear and shake gently. If You hear the banking of the balance pinions on the cap jewels then it has to much endshake. 

Check the pinion without cap jewels, You could see if there is to much sideshake. Here You can see a balance pinion with too much sideshake: 

 

Please push the balanc wheel with some soft tool like a brush for example

I suggest pushing back the balance cock with thumb meanwhile taking care of the balance alignment with some soft tool for example a toothpick to avoid friction. And if all in place then tighten the screw. 

 

[GeorgeClarkson]

7 hours ago, matabog said:

talking about the second video:  in the first half the balance pivot is not set right in the upper jewels; in the second half it apears to be overbanked - meaning the impulse pin is on the wrong side of the pallet fork horns.

...just thinking out loud...

Actually in the first half the balance cock is still not completely screwed down, hence the wobbling. About the over banking: I will check later today if that's the issue

[Cad101]

Your scaring me prodding it like that with your driver I can see a pivot breaking. And matabog's correct your pivot is definitely on the wrong side of your pallet fork.

[jdm]

18 hours ago, Cad101 said:

And matabog's correct your pivot is definitely on the wrong side of your pallet fork.

But with in that case the movement shouldn't run at all, instead it runs in the video.

[matabog]

It looks like it is hitting something. I suppose it was the pallet fork horn.

[Cad101]

Your right jdm it normally wouldn't run but at the start of vid 2 to about 35 seconds before he starts screwing down its definitely hitting the fork edge to stop it like that there's probably enough tension in the spring to send it back round it clears up when he tilts the balance and jewel and it drops into place at about at about 50 then he tightens cock and it binds.