Omega sweep second pinion friction spring - correct tension IS important

[mikepilk]

Not a question, but something I've learned that may be useful to others.

After cleaning an Omega 1012 the amplitude was low and all over the place - fluctuating between 220 and 240 deg. I couldn't get it any higher.  

The jewels, gear train, balance all look good.  

It took me a long time to identify the problem - I wasn't checking the gear train with the sweep seconds pinion fitted.
As soon as I fitted that, the problem was clear - too much tension on the friction spring (the spring pushes down on the pinion).

I knew the wrong pressure from the spring would make a difference, but I didn't realise how much. 

Now the amplitude is 280-290 deg. 

Another lesson learnt

[Chopin]

Yep, been in a similar situation with a different type of movement but same concept... Mine only made some weird noises and the seconds hand would stutter at times.

Why did they have to make watches so fiddly and complicated sometimes ?

[mikepilk]

1 hour ago, Chopin said:

Yep, been in a similar situation with a different type of movement but same concept... Mine only made some weird noises and the seconds hand would stutter at times.

Why did they have to make watches so fiddly and complicated sometimes ?

It does seem a weakness in the design, being so sensitive to the spring tension.

I've also had problems with the springs which push up not having enough tension, and the second hand slipper/stuttering. 

And the slightest tweek to the spring and the damn things break  

[rodabod]

It’s worthnoting the change in amplitude when the spring is fitted; it should just drop slightly when fitted. Say, as a rough ballpark, maybe 5 or 10 degrees. It need to be enough to eradicate shake on the pinion drive. 

[oldhippy]

You are learning fast grasshopper.

[Chopin]

1 hour ago, oldhippy said:

You are learning fast grasshopper.

Aren't we all ?

[mikepilk]

1 hour ago, oldhippy said:

You are learning fast grasshopper.

I'm learning, but not that fast - I had it in pieces 3 times before I found the error !

But persistence in finding errors is worth it You don't forget what you've learned the hard way.

A Smiths Imperial did try my patience recently - I had in in pieces 4 times before I discovered that it was the "new" mainspring I'd fitted that was useless  - not springy !  

[Deggsie]

I'm learning, but not that fast - I had it in pieces 3 times before I found the error !
But persistence in finding errors is worth it You don't forget what you've learned the hard way.
A Smiths Imperial did try my patience recently - I had in in pieces 4 times before I discovered that it was the "new" mainspring I'd fitted that was useless  - not springy !  

The more I learn, the more I realise I know very little. It’s a depressing thought [emoji3]


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[Simon1]

hi,

what the function of the sweep second pinion of Omega cal. 565 is please ?

is there sweep second pinion in Omega cal. 552 ?

My issue is that my Omega cal.565 stops every time I shake my hand, but it seems that the movement is not stopping, because watch is not losing time. Is that normal ?

Also,  is it the same for Omega Cal. 552 ?

I had same Omega before,  I don't remember second hand stoping that often from minor shake. The movement is supposed to be serviced,  so just wondering if that's normal

thank you

[rodabod]

Hi Simon. Does the seconds hand also “stutter”?

[TimeWerks]

Thanks for this post MikePilk, I just came across a similar problem with an Omega 1022.  The problem I had was the seconds pinion spring was bent out of shape and did not even engage with the wheel properly, so the seconds hand was not moving at all. (no power loss though :)

I removed the automatic module so I could access the spring and work on it.

Once I bent it back close to the right shape, I experienced the same problem you reported about power loss.  Many tweaks later, and the seconds hand is moving properly again, with amplitude back to good numbers again.

Cheers

[mikepilk]

Once you are aware of the problem, you can adjust as necessary.

I have a couple of the Omega 10xx, and they are not my favourites. They seem a bit flimsy and not as solid as previous generation Omega. But I think that's true of a lot of movements from the 70-80s. For me, the 50-60s is the peak in watch movements, where the design criteria was quality, not saving the last penny.

[JohnR725]

12 hours ago, TimeWerks said:

I just came across a similar problem with an Omega 1022.  The problem I had was the seconds pinion spring was bent out of shape and did not even engage with the wheel properly, so the seconds hand was not moving at all. (no power loss though :)

It makes you wonder who worked on the watch before you and why the spring is bent out of shape? Then there's the other strange problem of the pinion? The parts listing for this watch the image that part is not quality at all

It would be really nice to find a picture of the part in the original package but this is an image I found online

Then what was bothering me was here is an image from a 1012 and you'll notice the spring set up is entirely different? So wonderful ever modified your spring did something to the pinion also? But again it's it is working maybe it's fine

 

[JohnR725]

There were things bothering me about this discussion that took me a while to figure out the problem. In the image below it appears to be the spring may be pushing up? Normally when Omega has a spring pushing up the pinion has a pivot with a bridge to hold it in place so in other words the spring can push on something that stationary as opposed to this which appears to be floating?

To understand the problem with the above image we need another image of side view which I have below. In my image down below on the left-hand side it agrees with the image up above. But the only problem is the left-hand side is defective and the right-hand side image is the way it's supposed to look.

Then Omega if you can access the right documents does explain how and why this problem occurs. With the pinion floating around it might be assumed that you support it when putting on all the hands but you do not because as noted below if you do this small bush on the pinion will relocate out of position exactly what we see in the image up above.

 

Then Omega does not mention this but there is a possibility of also damaging the pinion and causing the bush to move to where it's not supposed to be when removing the hands. 

 

Edited Tuesday at 06:46 PM by JohnR725

[mikepilk]

13 hours ago, JohnR725 said:

There were things bothering me about this discussion that took me a while to figure out the problem. In the image below it appears to be the spring may be pushing up?

Well spotted John. Yes your spring is incorrect @TimeWerks, it should be pushing the pinion down in to the mainplate as shown in @JohnR725's pic, not up as you show it.

 

13 hours ago, JohnR725 said:

Normally when Omega has a spring pushing up the pinion has a pivot with a bridge to hold it in place

Just yesterday I was disassembling an Omega cal 601. The spring is pushing UP on the pinion, but the pinion has a pivot and own little bridge (actually a cock). 

 

[VWatchie]

On 4/23/2018 at 10:27 AM, mikepilk said:

(the spring pushes down on the pinion)

Hmm... In the picture, it looks like the spring pushes on the side of the pinion. In the Vostok 24xx movements, the spring pushes down on top of the pinion. That is, the Vostok pinion is not visible from above as it is in your picture. Perhaps the Omega spring presses on a round tab fitted on the arbor just under the pinion?

EDIT:
Had a better look at the following posts, and the answer is yes!

Edited 5 hours ago by VWatchie

[mikepilk]

3 hours ago, VWatchie said:

Perhaps the Omega spring presses on a round tab fitted on the arbor just under the pinion?

They can go over, under, or around (fork shaped) depending on the movement. You can see all types in the following thread, where I was asking how to support the pinion when fitting the seconds hand when the spring sits on top of the pinion (on a Longines 30LS).