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Omega 28.10 RA diagnosis checklist - experienced eye needed


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Dear all

I have a vintage 28.10RA that "runs for a few minutes then stops". I have added detailed ancillary info below but to cut to the chase, I have attached a video showing that the watch stops BUT will start again if I apply some pressure to the centre wheel (see link). Is this diagnostic of  a bad centre wheel? It appears ok under the scope.

 

 

Background

>Only parts I have replaced is pallet fork (prior had a bent pivot) and the mainspring

>I have cleaned and re-assembled and oiled the watch 

>The wheels seem to run very very smoothly with no pallet fork/balance

>Balance is good and swings cleanly

>If i remove balance and test spring, it is sluggish as seen below: 

 

Here are some additional photos as this forum was wildly helpful on my last effort and the group always asked for lots of images 

 

 

IMG_7238.jpeg

IMG_7237.jpeg

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First thing to check is if there is not clearance between balance and central wheel, as shown with arrows.

IMG_7237.thumb.jpeg.81425ea02832f9f2e0b64731033dcaab.jpeg.6010367c674f65c29416bb036a2d0576.jpeg

If You turn the movement over (dial up), does it run at all?

Why there is no screw on the balance cock?

You amplitude is so lo that no point to claim the movement runs at all. First ensure that balance does not rub on the center wheel. If this is not the case, then I want to see You free oscillations test, with the cock screw in place. Does the pallet fork have some axial free play?

Ah, now I remember...

On 1/13/2025 at 1:32 AM, tb1982 said:

2: I repeated the test for fork freedom and it wiggles around wit  a decent air puff (needs a solid and direct puff so not super slick but it moves)

Well, this is not correct. The fork must move by slightest reason, even by actuating the movement. See, remove the pallet fork and return it's cock in place, tighten the screws of the cock. Put something (like screw driver under the cock where shown with arrow and lift a little.

IMG_7238.thumb.jpeg.01899e3d3bb8be5836fc771163873023.jpeg.ccf2b01008a8b5a0cd9d1a4e83bc5316.jpeg

I would do this with the escape wheel in place, but not sure if it will be better for You to remove it, as it is easy to damage thing. The idea is to slightly deform the bridge as to ensure little more axial free play for the pallet fork. Then test the freedom of it's movement again...

You diagnostic of bad center wheel is a little naive.

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>balance is not touching centre wheel but I’ll show some footage of it running without pallet fork 

>thank you for the tip on pallet fork play, 

>I will also show you the wheel training running without the pallet fork 

appreciate your input. When it comes to watch making I am not only naive but also incompetent. Which is why I’m here in the “safe space” for new watch makers 

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The long pinion of the 3th wheel is not seen on the pictures, what happened to it?

Now I understand that this is different movement. So, don't lift the pallet cock, gave this advice thinking that this is the same movement from the first thread where the pallet fork was stiff. Try the axial free play and if it is normal and the fork moves free, everything there is OK.

Edited by nevenbekriev
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Please see new videos as requested

1: Balance wheel but no pallet fork....you can see balance does not foul with middle wheel

2: Pallet fork is a bit sluggish when viewed in isolation. The pallet fork pivots seem good, the lower pivot hole is a little worn but nothing crazy and is still "round" not oval? Any ideas

 

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I need a good picture of You hairspring from a side. What You do with this screw driver to the balance is pretty dangerous, but it for sure shows the free oscillations are poor and I don't believe that it has something to do with the cleaning.

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On 1/20/2025 at 7:26 AM, nevenbekriev said:

remove the pallet fork and return it's cock in place, tighten the screws of the cock. Put something (like screw driver under the cock where shown with arrow and lift a little.

On 1/20/2025 at 7:26 AM, nevenbekriev said:

The idea is to slightly deform the bridge as to ensure little more axial free play for the pallet fork.

Perhaps I am missing something, but what you're saying sounds absurd. If the end shake needs to be increased, the jewel should be adjusted, no?!

Just looked into it: The Omega calibre 28.10 RA does not have a jewel on the pallet fork cock. Instead, this movement uses a simple bushing for the pivot of the pallet fork on the cock side. Perhaps the only way to increase the shake is to do as you suggest. I must say it sounds somewhat "brutal", but I guess it is what it is.

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I notice in your first video you were testing it without the balance cock being screwed in place. You can't really learn anything by that as things are likely to be different with the balance properly secured. Make sure the balance moves freely in a fully assembled movement (except for the pallet fork) before looking for anything else. Since you suspect an issue with the centre wheel, make sure you do a free oscillation test with the centre wheel in a variety of different positions.

I'm not sure why you think the pallet fork is sluggish. In your test you were blowing it so hard it was bouncing off the banking pin back to its initial position. It's hard to tell how freely it's moving under those circumstances. You should be able to get the fork to swing by moving the movement: give it a twist on the bench, or hold it vertically and change its orientation. (I think that's what Neven meant by 'actuating' the movement.)

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2 hours ago, VWatchie said:

Perhaps I am missing something, but what you're saying sounds absurd. If the end shake needs to be increased, the jewel should be adjusted, no?!

Just looked into it: The Omega calibre 28.10 RA does not have a jewel on the pallet fork cock. Instead, this movement uses a simple bushing for the pivot of the pallet fork on the cock side. Perhaps the only way to increase the shake is to do as you suggest. I must say it sounds somewhat "brutal", but I guess it is what it is.

Lol it does sound a little barbaric H , maybe not as much as we imagine, I trust Nev even though I want to question it sometimes, I guess needs must in this case . As with everything in watchmaking it is how you approach what you are doing that matters. On a similar note the OP's approach to setting the balance in motion has me cowering behind my sofa.  @tb1982 please use a small artists paintbrush to do this, I dont think my heart is strong enough to survive watching that video clip again 😅

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Please don't move the balance with a screwdriver, certainly not "briskly" like that! If you want to see how the balance runs on its own, take out the fork, rotate balance 180 degrees, and release. It should easily oscillate for 30 seconds or more. You can rotate the balance carefully with a protected finger (finger cot on), or very gently with a small brush. Puffing gives some indication of its freedom, but it's unquantified.

 

It definitely doesn't look free in the video. That could be due to damaged pivots, improperly cleaned/assembled/oiled balance jewels, some junk in the "chimney" of the Incabloc, and as Neven has implied (and my gut is there too) a hairspring out of true. Could be other things too. Until the balance performs freely, it's pointless to spend time looking at anything else.

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22 minutes ago, Neverenoughwatches said:

On a similar note the OP's approach to setting the balance in motion has me cowering behind my sofa.  @tb1982 please use a small artists paintbrush to do this, I dont think my heart is strong enough to survive watching that video clip again 😅

I'm braver than you, hiding behind the sofa, you big softy. I just put my fingers over my eyes. hehe. 

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yes - the screwdriver on the balance looked way worse on camera.....i was trying to film it and move it carefully but could not see around the camera...will invest in a small brush...thanks everyone. lots of ideas to go back and try

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You don’t even need to buy a small brush.

You can gently and carefully use a toothpick, some pegwood, your finger (with a finger cot or glove) or an oiler to carefully turn the balance through 180 degrees and then release it and observe how long it oscillates for. 

Just take care to avoid any contact with the hairspring, and ensure you rotate the balance without applying any force in any direction other than that required to turn it. 

Mark

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2 hours ago, nickelsilver said:

Please don't move the balance with a screwdriver,

Decades ago I saw a Glashutte WW2 chronograph I was interested in, in a pawn show - not running. The owner unscrewed the back and to my sheer horror he took a 30 cm kitchen knife and tried to nudge the balance wheel!

Frank

Edited by praezis
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2 hours ago, RichardHarris123 said:

I'm braver than you, hiding behind the sofa, you big softy. I just put my fingers over my eyes. hehe. 

I could still hear it from behind the sofa 😅

53 minutes ago, praezis said:

Decades ago I saw a Glashutte WW2 chronograph I was interested in, in a pawn show - not running. The owner unscrewed the back and to my sheer horror he took a 30 cm kitchen knife and tried to nudge the balance wheel!

Frank

🤔 fortunately i can see and not hear the idea of this pawn show, I would feel as though I'd stumbled across a different kind of forum.......again.......for the 9th time this month........accidentally. 

I think it was meant to be pawn shop, i wonder if Frank is using the same dictation software as John 😉

1 hour ago, tb1982 said:

yes - the screwdriver on the balance looked way worse on camera.....i was trying to film it and move it carefully but could not see around the camera...will invest in a small brush...thanks everyone. lots of ideas to go back and try

I have always liked the idea of a brush, bristles will give way , steel will not...much. Accidents can happen when not completely focused, hairs of a brush are far more forgiving. I would thoroughly check the pivots of the balance,  a minor bend may go unnoticed, but if there are bends on both ends in opposite directions then the room for freeplay in the bearings would be reduced combined between the two.

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45 minutes ago, tb1982 said:

Here is the balance (demagnetized) on its own. I also cleaned and oiled top jewel. Thoughts? 

 

 

 

sorry to say, but this doesn't look good.

A puff like that should keep the balance going for a minute (or at least 30, 40... seconds).

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So.. this:

5 hours ago, nickelsilver said:

t definitely doesn't look free in the video. That could be due to damaged pivots, improperly cleaned/assembled/oiled balance jewels, some junk in the "chimney" of the Incabloc, and as Neven has implied (and my gut is there too) a hairspring out of true. Could be other things too. Until the balance performs freely, it's pointless to spend time looking at anything else.

 

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5 minutes ago, tb1982 said:

best guess is balance is no good? 

The balance could be 100% A-OK, and the hairspring is out of flat and touching the arms. There could be a bit of muck stuck to the tail of the balance cock, tilting it and killing the endshake (and a number of other possible causes). My gut is till on the hairspring. Can you get a pic from the side, showing the hairspring, and one from straight on top, with a full view of balance and hairspring?

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IMG_7291.thumb.jpeg.b74aa7d62375d62f68df3f160dcb7338.jpegIMG_7290.thumb.jpeg.89efc8527754af4db4905535176925d6.jpegIMG_7289.thumb.jpeg.f5614094003564032081b5426bd33d4b.jpegIMG_7282.thumb.jpeg.16cb5fc506d0f2991ddb71d93353ff2a.jpegIMG_7280.thumb.jpeg.69fa15f37b0a1d29bd5b7fc8e7beb77d.jpegIMG_7286.thumb.jpeg.7ac56dd429f4e16524147563a85e4ab7.jpegIMG_7281.thumb.jpeg.1a3f55b49929eb9c9e4ed23c0def4c10.jpeg

17 minutes ago, nickelsilver said:

The balance could be 100% A-OK, and the hairspring is out of flat and touching the arms. There could be a bit of muck stuck to the tail of the balance cock, tilting it and killing the endshake (and a number of other possible causes). My gut is till on the hairspring. Can you get a pic from the side, showing the hairspring, and one from straight on top, with a full view of balance and hairspring?

 

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19 minutes ago, tb1982 said:

IMG_7291.thumb.jpeg.b74aa7d62375d62f68df3f160dcb7338.jpegIMG_7290.thumb.jpeg.89efc8527754af4db4905535176925d6.jpegIMG_7289.thumb.jpeg.f5614094003564032081b5426bd33d4b.jpegIMG_7282.thumb.jpeg.16cb5fc506d0f2991ddb71d93353ff2a.jpegIMG_7280.thumb.jpeg.69fa15f37b0a1d29bd5b7fc8e7beb77d.jpegIMG_7286.thumb.jpeg.7ac56dd429f4e16524147563a85e4ab7.jpegIMG_7281.thumb.jpeg.1a3f55b49929eb9c9e4ed23c0def4c10.jpeg

 

the pictures aren't really super helpful like this.

 

38 minutes ago, nickelsilver said:

a pic from the side, showing the hairspring, and one from straight on top

with that, @nickelsilver refers to pictures like the following:

image.thumb.png.47be9f223bb727061dda51466e25c971.png

image.png.54cadfe710d40e1ce7f0879794535e0f.png

 

6 minutes ago, AndyGSi said:

Have you done anything with the jewels as that spring looks to be bulging out way too much.

image.png.e20f565046b72ee6f93e4fcf696893f5.png

good observation!

And one side of the spring is almost coming out

Edited by Knebo
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