ETA 2892A2 Amplitude

[Pip]

I’m working on a Longines with a 2892A2 movement. All cleaned and oiled, what sort of amplitude should I expect to achieve? I’m hitting 230/240 dial down and 210ish dial up on a full wind. I’m guessing it should be hitting 300?

 

 

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[oldhippy]

This should help you.

https://forums.watchuseek.com/f2/eta-chart-basic-details-eta-2824-2-2892-a2-7750-a-513566.html

[Pip]

This should help you.
https://forums.watchuseek.com/f2/eta-chart-basic-details-eta-2824-2-2892-a2-7750-a-513566.html

Thanks OH! So I’ve hit the minimum allowable but nowhere near the middle let alone the upper. I think I am going to clean and oil my pivots again.


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[Pip]

I’ve increased the amp by around 10deg by demagnetising the movement. I just learned the hard way that you have to stop the balance first!


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[HSL]

Just some thoughts about the amplitude in the 28XX series. 

To get maximal amplitude before regulating these beauties I use to let it take some time. If one follow the oiling scheme in the tech notes one should get a quite good amplitude. 

The important step in the process is to let the movement run for at least a day or two before starting regulating the movement with a time graph. If you measure the amplitude just after servicing you will get a lower reading which is natural. To get maximum lubrication one have to let it get worked in and spread out on the surfaces.

To gain maximum amplitude on these ETA Movements or any one else I guess it is of most importance to learn how to oil/grease the jewels on the pallet fork with for example Moeibus 9415. In my experience this boosts the amplitude significant.

To get an amplitude of 300 one have to do the complete service including main spring change.

When I get the amplitude to 280 or higher i begin the regulating work.

Hope these observations can help you in some way.

[oldhippy]

Try to remember to demagnetise the movement and the tools you are going to use first. It can save you a lot of time.

[Pip]

Try to remember to demagnetise the movement and the tools you are going to use first. It can save you a lot of time.

Good advice!

Just some thoughts about the amplitude in the 28XX series. 

To get maximal amplitude before regulating these beauties I use to let it take some time. If one follow the oiling scheme in the tech notes one should get a quite good amplitude. 

The important step in the process is to let the movement run for at least a day or two before starting regulating the movement with a time graph. If you measure the amplitude just after servicing you will get a lower reading which is natural. To get maximum lubrication one have to let it get worked in and spread out on the surfaces.

To gain maximum amplitude on these ETA Movements or any one else I guess it is of most importance to learn how to oil/grease the jewels on the pallet fork with for example Moeibus 9415. In my experience this boosts the amplitude significant.

To get an amplitude of 300 one have to do the complete service including main spring change.

When I get the amplitude to 280 or higher i begin the regulating work.

Hope these observations can help you in some way.

Thanks HSL.

I haven’t changed the MS on this one, looked ok though of course it’s not new.

I have just started using 9415 on the pallets so again the qualifier is that I may not be brilliant at doing this yet.

I’m up at 240 now. Hadn’t thought about letting it run for 24 hours, that makes perfect sense so thanks for the advice.


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[JohnR725]

7 hours ago, oldhippy said:

https://forums.watchuseek.com/f2/eta-chart-basic-details-eta-2824-2-2892-a2-7750-a-513566.html

You have to be careful when you look at a chart like that in that it doesn't explain the numbers? A better source of information is the manufacturing info sheet for the watch which I'm attaching. So specifically the minimum amplitude is after running 24 hours.

ETA 2892-A2 of manufacturing info.pdf

[Pip]

I let the movement run from a full wind straight after reassembly (which was showing at around 240amp and about +1spd) for around 24 hours and measured the following:


My thoughts on next steps are:
1. Disassemble and re-clean pivots and holes
2. Give the balance another dip in Perk
3. Do the oiling from scratch
4. Re-clean and reapply 9415 to the pallets

Anything I’m missing? Could this be down to the MS which I did nothing with apart from opening the cap and applying a spot of fresh grease to the barrel floor and lid and a drop of oil over the coils. I’m now wondering if that was a poor decision.

TIA
Pip



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[JohnR725]

You didn't mention what other lubricants you are using for the rest of the watch?

Then minor problem with 9415 a little is good too much is bad Omega has an interesting guideline for lubricating the pallet fork and it's depending upon the conditions of previous lubricants specifically whether is lubricated with Lubrifar As that changes the lubrication. But in any case they apply of very tiny little drop than 24 hours verify it meets their specifications and the use of 40 power microscope. So a very tiny bit a lubricated is important too much is bad but that's more of a high performance thing I doubt it's what affecting you unless you put huge blobs on.

I don't suppose you know the service history of the watch its prior condition before you serviced it?

Then I was rereading the entire discussion timing you did dial-up and dial down there was a discrepancy does the discrepancies still exist? Then you gave a dial-up and dial down you didn't give any of the pendant positions like wristwatch typically crown down what's that doing?

 

[Pip]

You didn't mention what other lubricants you are using for the rest of the watch?
Then minor problem with 9415 a little is good too much is bad Omega has an interesting guideline for lubricating the pallet fork and it's depending upon the conditions of previous lubricants specifically whether is lubricated with Lubrifar As that changes the lubrication. But in any case they apply of very tiny little drop than 24 hours verify it meets their specifications and the use of 40 power microscope. So a very tiny bit a lubricated is important too much is bad but that's more of a high performance thing I doubt it's what affecting you unless you put huge blobs on.
I don't suppose you know the service history of the watch its prior condition before you serviced it?
Then I was rereading the entire discussion timing you did dial-up and dial down there was a discrepancy does the discrepancies still exist? Then you gave a dial-up and dial down you didn't give any of the pendant positions like wristwatch typically crown down what's that doing?
 

You are right, I didn’t, so this is what was used:
9010; 1300; 9415; and a dab of 8201 on the barrel floor and cap. All from Moebius and all reasonably new.
The parts were US cleaned (small cheap domestic one I have) in small glass jars in a 40/60 mix of lighter fluid and white spirit and then rinsed in IPA before drying. The pallet was cleaned manually with pegwood and Rodico. The balance complete was dipped and very lightly agitated in Perc (perchloroethylene) and suspended and left to air dry. The cap jewels and holders we’re removed and agitated in Perc before further manual cleaning and oiling with 9010 and reinstalling.





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[nickelsilver]

Are you pegging your jewels? They really need to be spotlessly clean. In particular do the hole jewels for the pallet fork, and push the fork end (the slot) into brand new pithwood a few times. Check that no particules clung to it too. Roller jewel should be spotless.

 

Many (most) folks, even experienced professionals, often go for the mainspring when the problem is elsewhere. Yes, the barrel really does need to be in good order and clean but in my experience on modern pieces if the spring looks good and the barrel isn't eaten up where it rides the arbor or the wall (autos) amplitude worries come from other places. In a 2892 there's kinda "one spring", but on other older calibers it's usually possible to put a stronger spring in. It's a bad practice if it's compensating other correctable faults.

 

One small possibility in your case is the lubrication you've added to the barrel is letting it slip too much. Nonetheless I'd expect more amplitude especially after just winding up. You need a braking grease for the barrel wall, and theoretically no lube on tbe spring as its teflon coated.

[Pip]

Are you pegging your jewels? They really need to be spotlessly clean. In particular do the hole jewels for the pallet fork, and push the fork end (the slot) into brand new pithwood a few times. Check that no particules clung to it too. Roller jewel should be spotless.

 

Yes, I’m pegging the jewels and cleaning the hole jewels. However, maybe I am not doing it well enough. I’ll up my mag to x40 and try and take and post some pics to see what you guys think. As I think I stated earlier, my suspicion is that what I think I’m getting clean properly, I’m not. I’d like to crack this though as gaining amplitude is something I need to perfect to satisfy my need to become a better watchmaker.

 

 

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[JohnR725]

On 2/3/2019 at 11:07 AM, Pip said:

I haven’t changed the MS on this one, looked ok though of course it’s not new.

6 hours ago, nickelsilver said:

Many (most) folks, even experienced professionals, often go for the mainspring when the problem is elsewhere. Yes, the barrel really does need to be in good order and clean but in my experience on modern pieces if the spring looks good and the barrel isn't eaten up where it rides the arbor or the wall (autos) amplitude worries come from other places. I

So regarding the mainspring did you remove it from the barrel and did you clean it? If the mainspring in a prior servicing had been lubricated with some lubrication then we really can't assume that the spring is not going to be a source of a problem. Modern mainsprings come prelubricated so no lubrication is required on the spring itself. Breaking grease is required on the outer wall. If you'd remove the cap and the mainspring look clean other than lubricating the arbor if you didn't want to fool with it you would've probably been okay. But if you saw lubrication on the spring attempted to clean it without Removing the spring that's not going to be successful and then trying to put grease on it after the fact that may or may not work either. So with a watch that is having an amplitude problem mainsprings can be an issue. Not so much because thay are going to be set or go bad mainly because Of the possibility of sticky lubrication.

 

[Pip]

So regarding the mainspring did you remove it from the barrel and did you clean it? I
 

MS not removed from barrel. Just inspected and a little bit of barrel grease (8201) applied and a couple of small drops of HP1300 placed on top of spring.


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[Pip]

So here are some photos. It’s amazing how much crap you see at 40+
I used my microscope at 40x and then used my phone to take the pics at between x1 and x8 so there are some close ups. Quality isn’t as good as through my stereo scope of course and forgive the reflection of the ring light. Oh, and I’ve not disassembled to take close ups of the pivots tonight as it’s already after 11pm here and I have to clear all my kit up yet! Oh for a dedicated workspace...

Cap jewel hairspring side


Cap jewel dial side


Pallets, one from each side

what is that blob after it’s been run from full wind to nothing? That can’t be good, which means maybe we’ve found something!

Some other jewel holes





That should be enough to give an idea. I’m totally up for any criticism as I need to know what to do better. I simply must be able to be better at this.


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[rodabod]

I repeat this many time here, but with modern watches, they tend to have finer pivots and less overall torque which means that the faster end of the train must be perfectly clean to run well. In my opinion it's less likely that a significant loss of amplitude is a result of dirt bearings towards the barrel end of the train. It will affect it, but not as much.

Two simple tests I like to conduct in situations like these:

Run the mainspring down and remove the balance and pallets. Now turn the crown a little and observe the train running free. If it is running with very low friction then the escape wheel will recoil backwards immediately after it has come to a halt.

Place the balance back in the watch without the pallets. Excite the balance and observe how long it takes to come to a rest. If it's running with little friction then it should oscillate for a good minute or two. If it stops after a short amount of time then you know you have a problem.

[Pip]

I repeat this many time here, but with modern watches, they tend to have finer pivots and less overall torque which means that the faster end of the train must be perfectly clean to run well. In my opinion it's less likely that a significant loss of amplitude is a result of dirt bearings towards the barrel end of the train. It will affect it, but not as much.
Two simple tests I like to conduct in situations like these:
Run the mainspring down and remove the balance and pallets. Now turn the crown a little and observe the train running free. If it is running with very low friction then the escape wheel will recoil backwards immediately after it has come to a halt.
Place the balance back in the watch without the pallets. Excite the balance and observe how long it takes to come to a rest. If it's running with little friction then it should oscillate for a good minute or two. If it stops after a short amount of time then you know you have a problem.

Can you explain what you mean by excite the balance please? Do you mean to use my blower to get it moving or maybe to turn it manually to a certain degree?


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[rodabod]

Yes, a blower will do. Just enough to get it swinging a reasonable amount.

[Pip]

Balance took 1m 16s to come to a complete rest. There is a very slight backlash, and I do mean very slight, on the escape. More often than not though it just halts.

Can you tell anything about the jewels from the pics above? Do they look about right?


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[Pip]

Pallets re-cleaned and 9415 re-applied. Is this the correct amount?

Endstone re-cleaned and 9010 re-applied. No pics of that though.
Amp now sitting around 260/265. Getting better.



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[rodabod]

In my opinion there should be more oil on the pallet stones. Have a look at the BHI lubrication guide. However, it should run well with that amount only. 

Did you use an actual breaking grease on the mainspring and did the barrel wall show signs of wear?

[Pip]

Mainspring was only light touch.
Thanks for everyone’s help and encouragement; I got the amp up to near on 300 with 0.0 BE and +1 to +6 spd according to my TG. I’m very happy with that so it’s been cased and final test before return to its owner.


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[meanoldmanning]

Mainspring was only light touch.
Thanks for everyone’s help and encouragement; I got the amp up to near on 300 with 0.0 BE and +1 to +6 spd according to my TG. I’m very happy with that so it’s been cased and final test before return to its owner.


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Phil, what did you conclude was the culprit?


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[Pip]

Phil, what did you conclude was the culprit?


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I think partly my cleaning wasn’t as good as I thought it was, but the main issue was I think incorrect oiling if the pallet stones.