Seiko 6139B assembly help please

[Wdc]

 

Seiko 6139B assembly help

I have had mixed success assembling a 6139B and seeking help.  I have several 6139, 6138 movements and training myself to service them.   

A quick summery is as follows

1.       The 1^st tear-down, cleaning/servicing and assembly was flawless. The second the balance was dropped in it came to life running for two days, no-problem.

2.        For untold reasons I disassembled and assembled it again.  Smooth wheel train with backlash. Dropped in the balance and it will not run. The balance is smooth, springy, swing freely in one direction but stops at 90°, will not swing the normal +- 180°.

3.       I have Dissassy & assy the movement several time looking for problems, but all looks good, balance does the same, stops at 90°.

4.       Thinking I am not seeing something grabbed another 6139 disassembled, cleaned/serviced and assembled it, and the same stops at 90°.

5.       For whatever reason the pallet fork will not swing past center. Free and springy in one direction but stops dead center.

With the same happening to both movements I have eliminated a mechanical failure and must be something I am doing wrong on assy and prompting me to seek help.

Attached is a link showing the wheel train running smooth with the MS. I can post the balance stopping and its characteristics if it would help with the assessment.

Thanks in advance & Marry Christmas to all

Will

[Latvas]

 
Seiko 6139B assembly help
I have had mixed success assembling a 6139B and seeking help.  I have several 6139, 6138 movements and training myself to service them.   
A quick summery is as follows
1.       The 1^st tear-down, cleaning/servicing and assembly was flawless. The second the balance was dropped in it came to life running for two days, no-problem.
2.        For untold reasons I disassembled and assembled it again.  Smooth wheel train with backlash. Dropped in the balance and it will not run. The balance is smooth, springy, swing freely in one direction but stops at 90°, will not swing the normal +- 180°.
3.       I have Dissassy & assy the movement several time looking for problems, but all looks good, balance does the same, stops at 90°.
4.       Thinking I am not seeing something grabbed another 6139 disassembled, cleaned/serviced and assembled it, and the same stops at 90°.
5.       For whatever reason the pallet fork will not swing past center. Free and springy in one direction but stops dead center.
With the same happening to both movements I have eliminated a mechanical failure and must be something I am doing wrong on assy and prompting me to seek help.
Attached is a link showing the wheel train running smooth with the MS. I can post the balance stopping and its characteristics if it would help with the assessment.
Thanks in advance & Marry Christmas to all
Will

Check if the Stone on the roller is on the wrong side of the pallet, the balance must be turned in counterclockwise
And even then it must be carefully mingled into place, slowly but surely and there is no doubts when it falls into place, it just feels right

[Wdc]

Thank you, no doubt on the balance and escape wheel are seated in the jewels properly, everything is very free.

But you hit on something I have been uncertain for some time. When inserting the balance, is there a correct position with the balance stone and the pallet fork i.e. should I be on one side or the other of the fork, or just a proper position between the stone and fork?

Thank you

PS: Attached is a better look at the wheel train. I don’t think it’s the problem

 

Edited December 20, 2018 by Wdc

[Wdc]

OK, so I found this on the web

 “ jewel near the spindle of the bal. spring which has to be positioned in between the fork so that the spring can give the watch the impulse needed to keep it going. Try it with care when putting the balance spring in . ps. If the jewel is outside the fork, the balance would be locked -- thereby stopping the watch. The term is " overbanking "”.

So when I install the balance wheel, I need to I need to line up the roller pin (jewel) between the two forks on the pallet fork? Would someone please confirm?

If this is the case I am likely “Overbanked” with the fork to one side and just got luck the first assembly.  

Edited December 20, 2018 by Wdc

[Latvas]

Thank you, no doubt on the balance and escape wheel are seated in the jewels properly, everything is very free.
But you hit on something I have been uncertain for some time. When inserting the balance, is there a correct position with the balance stone and the pallet fork i.e. should I be on one side or the other of the fork, or just a proper position between the stone and fork?
Thank you
PS: Attached is a better look at the wheel train. I don’t think it’s the problem
 

The stone under the balance must be on the right side of the of the pallet, the watch wont tick if not, and when you agitate the balance with a blower with palletfork removed it must come to rest exactly in center between the banking pins , its a must, go on youtube, Mark on the watchrepair channel has a video where hes showing it


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[Latvas]

OK, so I found this on the web
 “ jewel near the spindle of the bal. spring which has to be positioned in between the fork so that the spring can give the watch the impulse needed to keep it going. Try it with care when putting the balance spring in . ps. If the jewel is outside the fork, the balance would be locked -- thereby stopping the watch. The term is " overbanking "”.
So when I install the balance wheel, I need to I need to line up the roller pin (jewel) between the two forks on the pallet fork? Would someone please confirm?
If this is the case I am likely “Overbanked” with the fork to one side and just got luck the first assembly.  

Exactly but its enough to place the roller pin on the right side, its a little difficult to place it exactly in the fork


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[Pip]

Not sure I’m following you, but if I am then the roller jewel on the balance needs to be in the centre of the pallet fork and not to one side or the other. If I’ve misunderstood you then apologies.

 

*edit: looks like conversation moved on while I was typing. This pic shows what I mean (pic from internet)

 

 

 

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[Wdc]

I can say that I have a tendency to swing the fork to the right when installing the balance. That would put the stone on the left. I will try both, stone to the right and centering in fork.

Thank you all

[Latvas]

I can say that I have a tendency to swing the fork to the right when installing the balance. That would put the stone on the left. I will try both, stone to the right and centering in fork.
Thank you all

Your welcome
its just a little hard to explain
Have a nice day


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[Wdc]

Good illustration thank you.

That does segway into another question I have been meaning to ask for some time “What is the straight pin between two pallet forks?” I have often wondered its purpose.

Follow-on:

 OK I see the illustration points it out as a “guard pin”, hard to imagen what its guarding against.

Edited December 20, 2018 by Wdc

[Nucejoe]

Hi, Guard pin has no function, it travels through the roller hollow, this to insure the impulse jewel is in the right position to receive impact from the fork. 

The fork is to remain in between the two banking pin,  if it gets out of there , it is refered to as overbanking.

The impulse jewel is to to be in between the fork( some call it fork jaws) 

In addition to advices so far, you may have knocked a pallet out of level. That is both pallet jewels  entery/ exit and the pallet all should be level with the escape wheel. To level hold both pallet jewels and pallet inside your tweezers ( leveled) and shellac.

Joe

 

 

 

[Nucejoe]

The pic shows passing hollow ( what I called roller hollow)  the guard pin is to pass though the hollow, to insure good postioning of the impulse jewel to receive fork impact.

Also correction. You may have knocked a pallet   "jewel ".  out of level.

 

[Wdc]

My thanks to everyone “we are off to the races”. Can not tell you if the impulse jewel was centered in the fork or off to the right as there is no space to see, but it fired.

Thanks again

[jguitron]

Quick observation,

Your second vid doesn’t show a smooth train wheel movement. In fact it stops abruptly and I see you giving the barrel a little push for it to get going again only to stop abruptly again.

Without the fork, the train should run continuously until mainspring is totally relaxed and the escape wheel slows to a soft stop. I suspect you have something impeding smooth function. Lint, debris, etc

Another quick thought... we all like to have a little power on the mainspring to see the balance wheel spring into action and make us feel like the masters of the universe! But engaging the impulse pin into the fork can be challenging particularly with power on. I suggest to release power completely, place the balance and wound. That’s worked for me several times.

Good luck!!




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