Newbee question (about mainsprings)...

PaulHelmuth · Nov 7, 2019

Related question (about alternatives to waiting on a spring from Cousins).

Archer
I can't tell you what to do, but if it were me, I would wait for the right spring. Keep in mind these are older movement, parts are likely worn slightly, and even with the right spring you may struggle to get amplitude. If you put in a spring that you know is already weak, then you are certainly not helping yourself.

Thickness is the least tolerant to change of the three mainspring dimensions. you can often get away with one where the width might be slightly less, or the length ay be a bit long or short, but strength is the one you don't want to compromise on.

@Archer - Hear you loud and clear. 👍

So, if I may ask a related question. I mentioned that it appears to me that the watch has been serviced in reasonably recent history. I saw no signs of trouble with the existing spring - or the barrel (the spring lays nice and flat with no kinks or unusual bends). If I wanted to use the current spring until the next service, what procedure would you recommend for cleaning and lubrication? Mostly thinking about the lubrication.

Archer · Nov 7, 2019

PaulHelmuth
So, if I may ask a related question. I mentioned that it appears to me that the watch has been serviced in reasonably recent history. I saw no signs of trouble with the existing spring - or the barrel (the spring lays nice and flat with no kinks or unusual bends). If I wanted to use the current spring until the next service, what procedure would you recommend for cleaning and lubrication? Mostly thinking about the lubrication.

You may want to view the series of posts I've made on watchmaking tips...

https://omegaforums.net/threads/basic-watchmaking-tips-oiling-part-1.62310/

The start of this thread lists a bunch of different threads that tackle individual subjects. I suggest reading them all, but there is one that specifically addresses the questions you have here:

https://omegaforums.net/threads/basic-watchmaking-tips-oiling-part-2-the-mainspring-barrel.71246/

Cheers, Al

PaulHelmuth · Nov 7, 2019

Archer
You may want to view the series of posts I've made on watchmaking tips...

https://omegaforums.net/threads/basic-watchmaking-tips-oiling-part-1.62310/

The start of this thread lists a bunch of different threads that tackle individual subjects. I suggest reading them all, but there is one that specifically addresses the questions you have here:

https://omegaforums.net/threads/basic-watchmaking-tips-oiling-part-2-the-mainspring-barrel.71246/

Cheers, Al

I'm on it!

I will read them all with great interest.

PaulHelmuth · Nov 13, 2019

Archer
That's a dog screw style, so Omega has replaced it with screw 1072709.

Happily for me - It appears that Omega (or maybe Cousins?) is packaging the newer style (1072709) as 2704.
What I received looks like the screws that were originally in my movement. So, I got luck there. 😀

-Paul

PaulHelmuth · Nov 23, 2019

Life being what it is - it has been a little while since I have posted an update.

Following a marvelous tutorial from @Archer - I have cleaned and (temporarily) reused the mainspring that was in the watch. It looks to be in good shape - but will still source a new one from Cousins when I can (which is looking like mid-late December).

Firstly, here are the new case/movement screws from Cousins. A little bit different profile to the head than the originals - but these are whole (not broken) and unmarred. Cousins sold them as Omega 2704 screws. I am happy to have the broken screw out and new ones in place.

Here's a frontal pic completely assembled with a new Crocodile strap from deBeer. I have an Omega (new modern) buckle coming for the strap. Won't be period appropriate, but will look nicer than the buckle from deBeer.

After originally reassembling and testing on timegrapher - I was seeing what I considered huge beat error. It was in the 1.4 to 2.0 ms range. This was huge in my experience - having never worked with vintage movements. And particularly none without a beat-adjuster built in to the balance assembly.

So, I purchased a balance tack and set forth putting this movement in beat. I quickly discovered that it's infinitely more difficult to put one of these movements in beat than one with an adjuster. I wasn't getting any closer than around 0.7-0.9. I believe this is fairly close to spec for this old movement, but still seemed like a huge error to me. So, I had a look at my copy of "The Watch Repairer's Manual" by Henry Fried and found his illustration and discussion about points to check quite helpful. In particular, the correct (ideal) position of the pallets with respect to the escape wheel at rest.

This discussion and illustration are on page #243 (Figure 5) of the second edition.

Following that point of reference, I was able to get the beat error in the 0.0 - 0.2 ms range. Which I am quite happy with. I think there is still some luck involved - as the adjustment is so small. But the first time I checked it after using the pallets and escape wheel for reference - this is what I found.

Here are a few different positions...

I haven't adjusted for time yet, but seems to be a somewhat large variation between some positions. Does anyone think that the variance here is anything to be concerned about?

I will usually adjust for time keeping based on wearing the watch - thus taking in to account the actual mix of positions that I put the watch through while wearing.

Will wait until I have a new mainspring before thoroughly evaluating the timing.

All-in-all I am very happy with my new old purchase. And satisfied with my decision to undertake the maintenance myself.

I do want to thank all that have assisted me here. I couldn't have done as well without them.

I would like to learn a bit more about identifying vintage Omega's and in particular, ones that were cased in England (Dennison).
Perhaps it merits a new/different thread - but my case is a 9KT 13322. So, how would this be identified? I'm pretty sure that Dennison also made this case in stainless steel (but not certain). Would the Dennison-cased watches be referred to by the dennison case #?
It seems to me that I have seen several different dials in these cases - but no unique numbering in the case that refers to dial option.

Is there some place to find more information on model/reference #'s for these? Omega seems to mark their cases pretty clearly.

Again - many thanks to all and hope to find some more vintage Omega watches to love.

-Paul

Deafboy · Nov 24, 2019

PaulHelmuth
I haven't adjusted for time yet, but seems to be a somewhat large variation between some positions. Does anyone think that the variance here is anything to be concerned about?

Have a look at this series of articles on watch adjustment.The first aspect to examine is the difference between dial-up and dial-down positions before tacklng other positions. In your case the amplitudes are similar (good) but rates are are quite different (+7 and +23 s/day). Are the regulators pins vertical and parallel?

BTW, assuming you have properly set the lift angle on your instrument, the amplitudes shown are quite good (e.g. 285 degrees horizontal, 250 vertical).

PaulHelmuth · Nov 24, 2019

[QUOTE="BTW, assuming you have properly set the lift angle on your instrument, the amplitudes shown are quite good (e.g. 285 degrees horizontal, 250 vertical).[/QUOTE]

@Deafboy,

Thanks for that info, I will read those articles and let you know what I see with the regulator.

I set the lift angle to 49 degrees - which I believe is correct for this movement?

-Paul

Archer · Nov 24, 2019

Yes, 49 degrees is correct.

PaulHelmuth · Nov 24, 2019

@Deafboy

At this point, I am just starting to read and research but am puzzled that dial-down position shows a slightly higher amplitude AND a faster rate?

I suppose this is why you suggested checking the regulator?

I will let you know what I see when I have a chance to look.
-Paul

Deafboy · Nov 24, 2019

The amplitudes are close enough that they are essentially identical.That excludes the possibility that the difference of rates is due to a lack of isochronism. The regulator pin spacing has a huge effect on rate. With that in mind, imagine the pins not being parallel, and that the hairspring droops a tiny bit with gravity, then the hairspring will interact with a different pin spacing in the dial-up position versus the dial-down positions, causing the rates to be different in those two positions.

As a corollary to pin separation on rate, one can improve isochronism (rate versus amplitude) of a watch by adjusting the regulator pin spacing. I do a series of measurements of rate versus amplitude for a position (e.g. dial down) and plot the results. Here's an example below from a Bulova 10AK movement. The blue points show the movement before adjustment that the rate varied almost 40 seconds from low to high amplitude. The red points show a much better result of the same movement after narrowing the regulator pin spacing and making adjustments to the shape of the hairspring. The rate now stays within a window of about 5 s/day over the full range of amplitudes. These adjustments are very delicate to execute though: practice on inexpensive movements!

PaulHelmuth · Nov 24, 2019

@Deafboy

Having a quick look at the balance, it didn't take long to find the problem.

The main problem being the goofball that made this mistake. 🙄

The regulator pins look great. However, while running through numerous adjustments to correct beat-error, I had gotten the hairspring out from the regulator pins and left it out 🤔

So - restoring the proper position of the hairspring, shows the following:

DU -15 sec/day; amp 290 deg.
DD -10 sec/day; amp 286 deg.

Those numbers seem pretty good.

Sadly, my beat error is now double what it was to start. It's now about 3.7 ms 🙁 But I think I can get that back in an acceptable range without too much trouble.

After I get all of that done, I'll move on to the vertical rates...

-Paul

Deafboy · Nov 24, 2019

PaulHelmuth
The main problem being the goofball that made this mistake. 🙄

The regulator pins look great. However, while running through numerous adjustments to correct beat-error, I had gotten the hairspring out from the regulator pins and left it out 🤔

LOL. Simple fix!
The difference in rates is much better now.

I suggest to plot the rate versus amplitude before looking at the vertical rates. It's easy to do: start with the watch completely unwound and wind a bit, measure rate and amplitude, wind a bit more, repeat this to full wind. It takes about a half hour to make the full set of data.

PaulHelmuth · Nov 24, 2019

Deafboy
LOL. Simple fix!
The difference in rates is much better now.

I suggest to plot the rate versus amplitude before looking at the vertical rates. It's easy to do: start with the watch completely unwound and wind a bit, measure rate and amplitude, wind a bit more, repeat this to full wind. It takes about a half hour to make the full set of data.

Okay - will do.

Is it important to get the beat-error somewhat closer to spec first? Or can that be ignored?

Seems to me that you would want that reasonably close when checking adjusting anything to do with timing/balance.

Yes/No?

Archer · Nov 24, 2019

The closer you get it to zero the better, but there is a tolerance to work with. Omega requires that it is no more than 0.8 ms in any position - like most factory tolerances, that's a little loose for me, but if you can get it to that or below, you are good.

For checking isochronism, a full set of positional timing values should be taken at full wind, and then 24 hours after full wind.

Cheers, Al

PaulHelmuth · Nov 24, 2019

Archer
The closer you get it to zero the better, but there is a tolerance to work with. Omega requires that it is no more than 0.8 ms in any position - like most factory tolerances, that's a little loose for me, but if you can get it to that or below you are good...
Cheers, Al

Thank you sir!

Archer · Nov 25, 2019

Just to elaborate on the issue of regulating pins, here's a view of some from a watch I serviced a couple years back - clearly this is not what you want:

This is a rather extreme example, and was done intentionally to help "cure" some other issues in the movement. So it required the pins to be straightened, and then I could properly repair the actual issues that the watch had:

So the gap between the pins is important, and honestly if you want to learn the effects of what this gap does, the best option is to get a movement that has the ETACHRON adjustment system on it, as the spacing of the pins can be adjusted very easily - just takes seconds. So you can open them wide, see what the timing is, then close them up and see the differences without having to do any delicate bending of pins. Note that if you bend these enough, they will work harden and snap, so it's best to make as few adjustments as possible on these, because you don't know how much the people before you may have bent these.

But as a start you want the gap between the pins here:

To be about the same as the thickness of the balance spring the goes through the pins. So the gap on either side should be about 1/2 the thickness of the spring. The coils must be centered and flat, everything concentric, and the spring needs to be centered between these pins. This is just the starting point, and measurement are taken and adjustments made from there.

Cheers, Al

PaulHelmuth · Nov 25, 2019

Archer
Just to elaborate on the issue of regulating pins, here's a view of some from a watch I serviced a couple years back - clearly this is not what you want...

Cheers, Al

Al - thanks! Great additional info on the topic (as always).

-Paul

PaulHelmuth · Nov 25, 2019

@Archer, @Deafboy

Happily, I was able to get back to a beat error of 0.0 - 0.1 ms 😀

Checking DU/DD at full wind:

DU: -36 sec/day; 314 deg
DD: -34 sec/day; 285 deg

I collected a set of amp vs rate data, but will have to plot before posting.

-Paul

Archer · Nov 26, 2019

The amplitude difference of 20 degrees between dial up and dial down is excessive, and not something that should be let go, but it will depend a great deal on your skill level if this is something you can correct or not.

Several possible causes for this, so first off would be that the balance jewels aren't fully cleaned, so the first thing I would recommend is that you clean the upper balance jewels again, oil them again, and see if this difference gets any closer. While you have the balance jewels out and apart, you should check the cap jewels for wear. Although these jewels are very hard, they do wear and it's not uncommon to find a divot in the jewel that looks like this:

Or this:

Or these, which both came out of the same watch and use the same movement yours does:

If you find the upper jewel has a divot, it should be replaced with a new jewel.

Second would be worn balance staff, that has become flattened on the end. Here's an example of what that look like under the microscope:

This is a more difficult thing to resolve, and it requires either burnishing of the pivots to make then round again, or replacement of the staff. If the rest of the staff is fine, then the end of the pivots can be rounded to increase the amplitude. This is after an initial rounding of the pivot you see above, and you can see a polished ring around the end of the pivot where it is been burnished with a small hand held tool:

Closer look:

But this wasn't enough, so I had to disassemble the balance:

Mount it in the Jacot tool:

End of the pivot comes through a hole in the lantern end:

And a burnisher is used to round the end even more - final result:

This may seem like advanced watchmaking, and I suspect to some it is, but these are the basics really of what need to be done to properly service a vintage watch like this.

Cheers, Al

PaulHelmuth · Nov 26, 2019

Archer
The amplitude difference of 20 degrees between dial up and dial down is excessive, and not something that should be let go, but it will depend a great deal on your skill level if this is something you can correct or not....

This may seem like advanced watchmaking, and I suspect to some it is, but these are the basics really of what need to be done to properly service a vintage watch like this.

Cheers, Al

Al,

Amazing additional content (as always).

I believe that I will be able to (re)clean, and inspect the jewels. I am pretty sure that my original oiling wasn't 100% consistent between the top and bottom jewel. I don't recall seeing any flaws in the end-stones, but may not have looked closely enough.

Not sure how much detail I will be able to see on the ends of the pivots - but it's beyond my skill and way beyond my equipment to burnish the ends of the pivots.

I will see what I can see and post my observations.

Huge thanks for sharing your valuable knowledge! Amazing pics too.

-Paul

Newbee question (about mainsprings)...

PaulHelmuth

Archer

PaulHelmuth

PaulHelmuth

PaulHelmuth

Deafboy

PaulHelmuth

Archer

PaulHelmuth

Deafboy

PaulHelmuth

Deafboy

PaulHelmuth

Archer

PaulHelmuth

Archer

PaulHelmuth

PaulHelmuth

Archer

PaulHelmuth

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