ETA 2836-2 Service Walkthrough

[VWatchie]

ETA 2836-2 Disassembly walkthrough here

ETA 2836-2 Assembly walkthrough here

When I started out servicing watches (Vostok cal. 2414) I was desperately looking for easy to follow walkthroughs and tutorials. That was several years ago. I did find a walkthrough on WUS, and I did find the YT-videos of former car mechanic Dan, the “Ratfaced Git”, and although his approach was much that of a car mechanic, rather than that of a skilled watch repairer (he hardly knew the names of parts, didn’t care much, and was proud of it), it inspired me endlessly and gave me - at that time a complete mechanical idiot - the courage to try it myself. Without those videos I’m not sure my interest would have taken off. I know Dan struggled with many difficulties in his life including cancer, and it has been close to three years since he published anything on his YT-channel. Anyway, I hope you’re still with us “Ratfaced git” and I say thank you for the inspiration and dedicate this walkthrough to you.

In ETA’s technical communication for calibre 2836-2 the assembly is made in seven steps in the following order:

1. Keyless works
2. Train of wheels
3. Mainspring barrel and bridge
4. Balance assembly
5. Self-winding mechanism
6. Dial train (/motion works) and the calendar works part 1
7. Dial train (/motion works) and the calendar works part 2

However, if you follow my assembly procedure, I put it together in a different order as I find it more convenient and wish to test the running of the watch as soon possible, that is, as soon as the train of wheels, barrel, and balance have been replaced. If at that point it’s not running well, I can more easily deal with it before continuing on with the assembly. Also, should problems arise at a later stage I’ll know it’s (very likely) not related to the train, barrel or balance. The downside, of course, is that the balance is exposed to potential damage for a longer period, although it can of course be removed. So, here are the steps of my assembly procedure:

1. Train of wheels
2. Mainspring barrel and bridge
3. Balance assembly
4. Keyless works
5. Dial train (/motion works) and the calendar works part 1
6. Dial train (/motion works) and the calendar works part 2
7. Self-winding mechanism

Apart from the click spring and the pallet stones, the oiling suggestions follow ETA’s technical communication.

Finally, I make walkthroughs for my personal use and enjoyment. They are not meant to be tutorials (for that I wholeheartedly recommend watchrepairlessons.com), but I like to share them in case there’s someone who would find them useful.

So, without further ado…

Edited April 20, 2021 by VWatchie

[VWatchie]

 

 

[VWatchie]

 

[HSL]

Good stuff as usuall, nice work...

[Nucejoe]

Excellent presentation as usuall. 

[Endeavor]

Excellent & a stunning walk-through

Fantastic, clearly many painstaking hours of work; this one should be pinned

[dadistic]

Very, very nice production. 

Really outstanding walkthrough!

[Geo]

Excellent post!

I am about to repair one of these movements this week after a few years away from the hobby and this will definitely come in very handy.

 

[dadistic]

Geo!

Good to see you back.

[Graziano]

Hi there Vwatchie ,my that is excellent work ,your photography is crisp and shows how clean that movement is . Thanks for taking the time to display .

Cheers Graziano

[Jon]

@VWatchie That's really great work!

Simply presented with plenty of pictures that speak a thousand words.

You've got a talent for teaching!

[VWatchie]

7 hours ago, Jon said:

You've got a talent for teaching!

Thank you very much for your kind words @Jon! I actually work as a teacher. However, I teach programming (C#/.NET/SQL) and not about watches. I enjoy doing watches (real things) more than programming (virtual things).

[alibababoombap]

Amazing walkthrough! Could I ask what camera you're using for these shots? The closeups are so crisp!

[VWatchie]

3 minutes ago, alibababoombap said:

Amazing walkthrough! Could I ask what camera you're using for these shots? The closeups are so crisp!

Thanks for you kind words. I simply use an iPhone 8 and an inexpensive $10 clip-on macro lens. I used to have an iPhone 6 and it worked just as well, but the battery died and I had to "upgrade". The "secret" is the lighting, and I always support my hands against the table and move the phone back and forth to get the best possible focus. It takes some practice and experimenting. In the beginning it used to happen that I dropped, or almost dropped the phone on the movement, which can lead to some pretty dramatic damage, but after some practice and experience I got the hang of it.

[TimpanogosSlim]

Thanks for this. 

Taboo as the subject is, I am inching toward a frankenwatch project involving a 2nd hand 2836-2 movement. 

I acquired a NOS case and dial of a Helvetia President watch. The hands are pretty standard fare. The 2836-2 and cousins seem to be dimensionally compatible with the case and i can design and 3d print my own spacer if needed, and the 2836-2 is superior to the original movement so as frankenwatches go, considering i rarely sell anything and would never sell this project without extensive documentation, i figure it is not too egregious. 

The 2836-2 bears dial and hands and rotor from a Wenger ("Swiss Military") watch and my timegrapher confirms that it is a 28800bph movement and running strong so i have doubts that it could be fake. It is certainly a loose movement that is at least 5 years old so some service is in order. 

I have 9010, D5, and 9415. I will probably use Nye PML Stem Grease on the winding components because i have it and it is excellent. I have 8302 natural grease with disulfide and i am under the impression that it is an acceptable braking grease if not as ideal as a couple other moebius products. Remains to be seen if i can be talked into Lubeta v105 as well. It could happen. It could also happen that i might just put on the 10x loupe and put a dab of something on several spots of the reversing wheels. 

I'll read through this at least a couple more times before i dive in. 

[Klassiker]

I made good use of this last weekend. Thanks again!

[GuyMontag]

Fantastic write up!

I have a question on the lubrication shown here:

 

 

Looking at the photo and the tech sheet I'm not clear if the 9010 goes on the rim of the hole where the pinion would rest or on the inside wall. I would assume on the inside wall since the tech sheet doesn't call for any oil on the "bump" on the seconds wheel?

[Jon]

Very good question and it will be a bone of contention, as it is regarding lubrication.

Personally, I don't lubricate the hole. If you were it would be just on the inside of the pipe. The reason I lubricate the fourth wheel rather than the hole is because, if the hole if lubricated with 9010, then most of the fourth wheel arbor will be coated with 9010 as it is pushed into position through the pipe. If the fourth wheel arbor is lubricated with 9010 like I've shown in the pic, then it won't do that. When fitting the wheel only the 9010 will reach the pipe when the correct part of the arbor does. Job done. You have to give the ETA schematic service manuals a big pinch of salt in my opinion. just look at how they get you to oil the cap jewels by putting 9010 on the chaton! Enough said...

 

 

On 12/26/2021 at 6:30 AM, TimpanogosSlim said:

I have 8302 natural grease with disulfide and i am under the impression that it is an acceptable braking grease

I'd be interested how that goes? I tend to use Moebius 8217, as I've had good results with brass, ali and steel barrels. Also what type of barrel are you using it with? Always good to learn a new way. Do you add the disulphide to the grease? If so, where do you get it from? I've heard it has really good properties needed in the barrel.

[VWatchie]

I'm afraid I don't know but I believe you're right. Unfortunately, I can't remember how I interpreted the tech sheet when I assembled the movement, and so I don't remember how I oiled it. Anyway, I would think that a very small drop of 9010 on the 4th wheel pivot should be OK too.

Here are a couple of pictures from ETA's technical documentation for the 2836-2 calibre:

[Jon]

Thanks @VWatchie Great pics! There are many ways to skin a cat. As long as the way one uses works, that's what counts!

BTW, Absolutely great walkthrough you presented there! Very precise and succinct and easy to follow. It will be a massive help for those wanting to service this movement.

Edited May 27, 2023 by Jon

[GuyMontag]

Thanks, that makes sense.

[VWatchie]

9 hours ago, Jon said:

When fitting the wheel only the 9010 will reach the pipe when the correct part of the arbor does.

Your reasoning makes a lot of sense @Jon. So much so that I'll be following it in future services of movements having a centre seconds hand.

9 hours ago, Jon said:

You have to give the ETA schematic service manuals a big pinch of salt in my opinion.

I agree again. They leave quite a bit to be desired and in my ETA 2892-A2 walkthrough I make the following reflection:

"In ETA's documentation, the assembly of the movement begins with the keyless works, then the train of wheels and then the barrel bridge. The crucial problem with this arrangement is that it is physically impossible to mount the barrel bridge if the train of wheels is already mounted. It is also very fiddly and difficult to baste the end of the winding stem into the winding pinion hole because the hole for the winding stem in the main plate is both open and tapered and therefore does not hold the winding stem.

It surprises me, but it seems like no watchmaker has proofread ETA's technical documentation. Alternatively, ETA follows an established practice and expects those using the documentation to understand that the assembly order in the document is not significant.

I am also somewhat sceptical of ETA's recommendations regarding lubrication. Where we traditionally use grease, for example in the keyless works, ETA chooses mainly oil (HP-1300). I guess that ETA treats all parts of the movement with epilame (Fixodrop) and that oil may then be a better alternative. For better or for worse, my service walkthrough follows ETA's lubrication recommendations."

ETA's schematic service manuals are helpful but there's definitely room for improvement.

[GuyMontag]

It also seems odd that they call for epilame on all of those parts but not on the pallet jewels or escape wheel.

[VWatchie]

14 hours ago, GuyMontag said:

It also seems odd that they call for epilame on all of those parts but not on the pallet jewels or escape wheel.

I'm guessing that ETA expects that the epilame (Fixodrop) treatment they give the entire movement will last several service cycles, but my experience tells me that epilame is not very durable. It may, in turn, depend on my choice of cleaning liquids and type of epilame. Chemistry is complex. I usually now treat all parts of the movement, with some exceptions, that come into contact with oil and grease with epilame and hope that it will extend the service interval. I use the epilame recommended by ETA in their service sheet (Moebius Fixodrop ES/BS 8981)

I understand that @JohnR725 has indicated on several occasions that ETA's manufacturing documents state that the "whole" movement is treated with epilame.

[JohnR725]

1 hour ago, VWatchie said:

I understand that @JohnR725 has indicated on several occasions that ETA's manufacturing documents state that the "whole" movement is treated with epilame.

minor correction here Omega currently epilam's just about everything. There's only a couple of parts they don't like the complete balance wheel for instance. I believe they also treat every single watch now it's the final rinse in the cleaning process. then they treated every single time the watch is cleaned because they claim the modern cleaning machine will strip off the old epilam.

Then for Omega if you go back to 1957 they do not recommend treating basically the pallet fork they specifically comments on that because they perceive it would stick to the banking pins. Of course this is the old day of the old epilam which is made a stearic acid. so basically the entire watch except the pallet fork is to be treated and not the balance complete as they were concerned about the roller table sticking. But the balance staff is to be stuck in the pith wood with the epilam for the balance pivots.

Then for the manufacturing information of eta as far as I know for every single document I've ever seen the pallet stones are treated. The balance staff is treated and escape wheel. This also applies for Sellita who produced technical manuals that look basically identical to eta.

so basically Swiss watches use a heck of a lot of epilam whether it's mentioned in service bulletin are not. As always the problem with technical literature is we seldom get it all in one place although Sellita for their technical guides to put all the manufacturing information in there so at least it's more complete.  then of course there's the problem of the various companies have supplemental information that often times we didn't even know existed. Like Omega has a lot of supplemental information not found in the technical sheets.