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Omega 30T2: Safety pin too long?


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Hi All,

I started talking about this project in a previous post, but I thought I start a fresh thread, since this a new issue.

I have a non-running 30T2.  I believe the problem is with the balance.  It swings for a bit but loses amplitude quickly and invariably (and abruptly; see vid below) settles around the center position -- i.e. with the pallet fork lying between the banking pins.  This is with or without power. 

There is one situation where it continues to run: when it fully wound and I apply additional torque via the crown.  I concluded that force is being transferred effectively to the pallets, but the balance is too strongly damped to sustain motion.  I see no problem with the train of wheels, mainspring, winding, etc.

Following the Fault Finding course, I performed some tests.  One result stood out:  with the balance wheel held fixed at zero rotation (with the pallets lying at the midpoint between the banking pins), the pallet fork is absolutely stiff -- no play.  Mark suggests this could indicate the safety pin could be too long, causing it to "foul" the safety roller.

I am hesitant to file down the safety pin right away, since I aspire to "do no harm".  Is the diagnosis really conclusive?  Is there any other possible cause of this symptom (pallet stiffness at zero degrees), for instance that the impulse pin fits too sungly within the pallet fork.

Thanks for your interest and help.

Gabe

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This is a non-inca 30T2. Before you start looking at the safety action in more detail, are you absolutely sure that that balance end-shake is ok? A broken or very worn pivot can cause these sorts of symptoms as it puts the roller out of alignment with the lever. Does it act the same with the movement flipped over so that it is dial-up?

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2 minutes ago, rodabod said:

This is a non-inca 30T2. Before you start looking at the safety action in more detail, are you absolutely sure that that balance end-shake is ok? A broken or very worn pivot can cause these sorts of symptoms as it puts the roller out of alignment with the lever. Does it act the same with the movement flipped over so that it is dial-up?

Hi there, thanks for the comment.  It is interesting to know that a worn pivot can cause these symptoms too. 

Yes, there is indeed some endshake, though I'm not sure if it is too much.  It does seem somewhat more than other movements I have on hand.

However, I did lift the movement upside down above my head and the motion of the balance seemed very similar.  To my eye, the pivots look undamaged and they seem to sit will in the pivot holes of the jewels when I look under magnification.

Stilly, perhaps there is enough wear on the pivots to be causing this behavior.  Any ways I might test this idea further?

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To test it, be particularly careful as there is not antishock: use something gentle like an oiler to push the balance rim up and down. It’s not easy to describe how much it should move as it depends obviously on the balance wheel diameter. It’s probably going to be in the vague region of about 1/4 of the thickness of the balance rim on a watch like this. If you are more confident, then grab the rim with fine tweezers. 

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6 minutes ago, rodabod said:

To test it, be particularly careful as there is not antishock: use something gentle like an oiler to push the balance rim up and down. It’s not easy to describe how much it should move as it depends obviously on the balance wheel diameter. It’s probably going to be in the vague region of about 1/4 of the thickness of the balance rim on a watch like this. If you are more confident, then grab the rim with fine tweezers. 

Hmm, I would say it's less than 1/2 rim thickness, maybe around 1/4.  Here is a vid:

 

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Perhaps you could remove the pallet (and put the balance complete back) and see if the balance behaves as expected with a smooth motion that gently drops of as it looses energy ? You could use an air blower to just "puff" some air on the mounted balance to get it to move and that should be sufficient. 

That should show you if the problem lies with the balance or the pallet (or elsewhere).

Edited by Flubber
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1 hour ago, gaber said:

Hmm, I would say it's less than 1/2 rim thickness, maybe around 1/4.  Here is a vid:

 

Hi, that seems quite a lot, though not necessarily to the extent that it is a problem. It is hard to tell by watching a video. 
 

Do you want me to show you a good example to compare to?

Also, take Flubber’s advice and check that the balance oscillates freely without the pallets if you have not done this already. 

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1 hour ago, rodabod said:

Hi, that seems quite a lot, though not necessarily to the extent that it is a problem. It is hard to tell by watching a video. 
 

Do you want me to show you a good example to compare to?

Also, take Flubber’s advice and check that the balance oscillates freely without the pallets if you have not done this already. 

I would appreciate the comparison, rodabod, thanks for offering!

I did try what Flubber suggested, and I thought it was improved without pallets.  Let me do it again for the camera:

Without the pallets, one finds the oscillations can sustain for longer.   But, on second thought, comparing with my unitas 6497, it is still poor to be honest.  I suppose I shouldn't rule out worn pivots as contributing to this behavior...

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You are showing end shake in the vid. Excess end shake dose not alter the distance between guard pin and roller table, side shake dose. Just observe pivots in jewel holes if holes are too big a round for pivots, its either worn/ wrong pivot or damaged/ wrong jewel.

Balance held in zero and one other position, the fork gets stiff, that indicates bent pivot or a fault at the roller table, out of round table.

The oscilator not running, reduces the chance of true observance in FU and FD positon, unless you can make sure the staff falls down on respective jewels as you flip the movement over.

You last vid above confirms a broken/ bent pivot or broken jewel.

 

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5 minutes ago, Nucejoe said:

You are showing end shake in the vid. Excess end shake dose not alter the distance between guard pin and roller table, side shake dose. Just observe pivots in jewel holes if holes are too big a round for pivots, its either worn/ wrong pivot or damaged/ wrong jewel.

Balance held in zero and one other position, the fork gets stiff, that indicates bent pivot or a fault at the roller table, out of round table.

The oscilator not running, reduces the chance of true observance in FU and FD positon, unless you can make sure the staff falls down on respective jewels as you flip the movement over.

You last vid above confirms a broken/ bent pivot or broken jewel.

 

Hi Nucejoe, thanks for all the thoughts!

It was suggested that end shake would reveal worn pivots, and this could cause the roller to go out of alignment with the guard/safety pin.  Perhaps side-shake would also be large in this case, altering the distance between the guard pin and roller?

I examined the top and bottom jewels under 10x magnification and they appeared undamaged -- perfect tiny circular holes, no visible cracking.  The the holes are so small, it is pushing the limits of my magnification, and I could not get a useful picture.  The do not appear to be too large for the pivots.  The size matches the pivots as far as I can tell.

You suggest also a problem with the pivots.  I did manage to get a decent photo of them; see below.  It was challenging!  What do you think?

 

IMG_20200830_182050_exported_933_1598804853526.jpg.8a0f847d5448ebd0dec4b612cb47737c.jpgIMG_20200830_181959.jpg.f4465b3c3cfa57012a560b8befee582a.jpgIMG_20200830_182453.thumb.jpg.85b666beba8ab8f1723e5edc52778ec6.jpg

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Roller table appears out if round, though roller hollow may sit just about right !   table can foul the guard pin at zero balance angular position. This stiĺl doesn't explain reluctance of oscilator with fork removed.

The inner side of balance jewels facing pivot shoulders would have to both be damaged to retard the balance.

So, its either a fault at pivot, staff, jewels or balance rubbing on something.

I cant quite tell from the vids, if there are end stones,  the design dont want pivot shoulders sit on jewels facing them in case of end stones.

 

 

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I’ve attached a video of a running 30T2 of a very similar vintage to yours. It works fine. 
 

There is something not right about your balance wheel alone, so forget about the interface with the lever just now. It seems to stop very suddenly - does it also do the same with the watch flipped over so that it is dial-up?

 

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3 minutes ago, Nucejoe said:

Dr ranfft shows ebd stones on 30T2. 

Have you removed end stones to see underneath?

 

Nucejoe, I removed the bottom end stone, and everything looks OK there.  For the top, I'm afraid I haven't figured out yet how to remove it.  There are no screws!  It looks like the following picture (not mine; posted by Mark for a repair)

 

post-1-0-97044800-1419082178_thumb.jpg.8bcacc1aa95a5bcab3628b4a1c052f50.jpg

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4 minutes ago, rodabod said:

I’ve attached a video of a running 30T2 of a very similar vintage to yours. It works fine. 
 

There is something not right about your balance wheel alone, so forget about the interface with the lever just now. It seems to stop very suddenly - does it also do the same with the watch flipped over so that it is dial-up?

 

FullSizeRender.mov

Thanks rodabod!

Yes I've experimented by turning it over and on its side.  Every side-up I try produces a similar behavior.  Maybe dial up is slightly worse, if I'm fishing for a difference :).

Edited by gaber
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20 minutes ago, Nucejoe said:

Roller table appears out if round, though roller hollow may sit just about right !   table can foul the guard pin at zero balance angular position. This stiĺl doesn't explain reluctance of oscilator with fork removed.

The inner side of balance jewels facing pivot shoulders would have to both be damaged to retard the balance.

So, its either a fault at pivot, staff, jewels or balance rubbing on something.

I cant quite tell from the vids, if there are end stones,  the design dont want pivot shoulders sit on jewels facing them in case of end stones.

 

 

Nucejoe, if I understand you correctly, I would need to inspect the inner surface of the upper and lower jewels for some kind of damage that could create drag on the pivot shoulders.  I can see well enough that pivot holes are perfectly circular, but I'm not sure how to check for surface damage.  There is no visible cracking....

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2 minutes ago, gaber said:

Nucejoe, if I understand you correctly, I would need to inspect the inner surface of the upper and lower jewels for some kind of damage that could create drag on the pivot shoulders.  I can see well enough that pivot holes are perfectly circular, but I'm not sure how to check for surface damage.  There is no visible cracking....

Since the oscilator doesn't want to swing freely both in face down FD and FU positions, we need to blame both jewels inner surfaces, kinda unusual. So I rule that out for now.

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18 minutes ago, gaber said:

Nucejoe, I removed the bottom end stone, and everything looks OK there.  For the top, I'm afraid I haven't figured out yet how to remove it.  There are no screws!  It looks like the following picture (not mine; posted by Mark for a repair)

 

post-1-0-97044800-1419082178_thumb.jpg.8bcacc1aa95a5bcab3628b4a1c052f50.jpg

The jewel hole is held by that 3-sided piece of metal. There is a slot on the inside. It can turn a small number of degrees anti-clockwise to remove. Use a screwdriver of the same width as the slot. 
 

However, you should be able to see the condition of the jewel hole under strong light and magnification. 
 

When you set the balance oscillating when testing, I would try to observe if anything is fouling the balance wheel, roller, or hairspring which is causing it to stop. 

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pivots length looks alright, but burred or perhaps somewhat dirty or rusted, to better clean I stick them pivots in soft pegwood several times.

That three sided retaining washer tell me, you didn,t remove it to check the jewels, it admittedly looks unusual and scary to remove.

 

 

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10 minutes ago, Nucejoe said:

pivots length looks alright, but burred or perhaps somewhat dirty or rusted, to better clean I stick them pivots in soft pegwood several times.

That three sided retaining washer tell me, you didn,t remove it to check the jewels, it admittedly looks unusual and scary to remove.

 

 

The photo is quite grainy since I zoomed in digitally.  In the eyeglass, the pivots don't look corroded or dirty. 

You are right, I did not dare to remove this three-sided washer.  But I may do it next.  Perhaps it needs to be cleaned of old oils, dirt, etc?  There is nothing I can observe, but it may be worth a try.

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22 minutes ago, rodabod said:

The jewel hole is held by that 3-sided piece of metal. There is a slot on the inside. It can turn a small number of degrees anti-clockwise to remove. Use a screwdriver of the same width as the slot. 
 

However, you should be able to see the condition of the jewel hole under strong light and magnification. 
 

When you set the balance oscillating when testing, I would try to observe if anything is fouling the balance wheel, roller, or hairspring which is causing it to stop. 

That is very helpful, thanks! 

I did examine the jewel under my best magnification and lighting and I think it's OK.  I guess I have lingering worries that I maybe there is something lurking in there I cannot quite see, so I think I will end up pulling that jewel setting apart.

I guess my plan of attack, following the advice I'm getting, is to re-inspect and clean the jewels, and then proceed to remove anything obstructing a clear view of the balance wheel (train bridge, etc), so I can see for sure if it is rubbing anywhere!

Thanks again!

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Hi  What I did notice in the video of the balance moved by puffing air was that the balance comes to rest abruptly in the same spot,  Note the position of the balance arms when coming to rest it does not come to rest smoothly as the power diminishes, So from that I suspect the balance has a problem as suggested bent/ worn pivots being most likley.  Other than substituting the balance its hard to prove.

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18 minutes ago, gaber said:

The photo is quite grainy since I zoomed in digitally.  In the eyeglass, the pivots don't look corroded or dirty. 

You are right, I did not dare to remove this three-sided washer.  But I may do it next.  Perhaps it needs to be cleaned of old oils, dirt, etc?  There is nothing I can observe, but it may be worth a try.

Before you remove them washers, I drop a bit of lighter fluid or naphta on both jewel assemblies, it will penetrate inside the assembly in a second and temporarily softens the old oil, congealed, gummed up what have you and lets the oscilator pivots free, puff air on the rim of the balance to keep it swinging,  If the issue is one of lube you would see the oscilator take off flying.

 Try not to get any on hairsprings, stops it as coils stick together, even then you can get rid of the lighter fluid on HS coil by puffer. 

judging from the vid, I don't think dried oil causes an issue to this extent.

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33 minutes ago, watchweasol said:

Hi  What I did notice in the video of the balance moved by puffing air was that the balance comes to rest abruptly in the same spot,  Note the position of the balance arms when coming to rest it does not come to rest smoothly as the power diminishes, So from that I suspect the balance has a problem as suggested bent/ worn pivots being most likley.  Other than substituting the balance its hard to prove.

Hi watchweasol.  Right, the abrupt stop at the same spot seems like an important clue.  But did you catch a look at the photos I took of the pivots?  They seem to match pictures of new pivots I see online. 

IMG_20200830_182050_exported_933_1598804853526.jpg.ad4ca9b12bea0fd5986af12e4776814d.jpgIMG_20200830_181959.jpg.fd620a2dc0066f89b2e67a2c13c337d8.jpgIMG_20200830_182453.thumb.jpg.057d388251786aed05b26bdebfacb593.jpg

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37 minutes ago, Nucejoe said:

Before you remove them washers, I drop a bit of lighter fluid or naphta on both jewel assemblies, it will penetrate inside the assembly in a second and temporarily softens the old oil, congealed, gummed up what have you and lets the oscilator pivots free, puff air on the rim of the balance to keep it swinging,  If the issue is one of lube you would see the oscilator take off flying.

 Try not to get any on hairsprings, stops it as coils stick together, even then you can get rid of the lighter fluid on HS coil by puffer. 

judging from the vid, I don't think dried oil causes an issue to this extent.

Thanks, I'll give that a try first.

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