Broken balance pivot, cheating seller! Any chances to get it repaired?

[Endeavor]

I bought a nice looking Art Deco 0.900 silver cased pocket watch. Pictures looked good, seemingly untouched movement and described as; movement starts up during short test. Seller had a high reputation and was/is selling more pocket-watches.

It's a Zentra Tavannes. I believe Zentra Tavannes was a cooperation of movement manufacturers and distributors, so the movement is, at least for me, an unknown.

The watch came today and ran, poorly, only with dial-up. A quick check revealed that it had a broken balance staff pivot. Currently I'm in discussion with the seller, but he gives me the usual story that he didn't know and he's not a watch maker. Being bought on a German local website, I'm not standing strong.

Is there anything to save?

Normally I don't touch / buy watch with a broken balance staff. Even though I do have a stacking set, I never changed a balance-staff out. Added to my problem, it's currently an "unknown" movement and therefor no idea where to start or to look.

 

What do we know: the movement (Breguet hairspring) is 38mm (main body) / 38.7mm (including dial edge) in diameter and it has "Tavannes Zentra" 121 stamped on it. Perhaps luckily (?), there is one more clue, underneath the balance wheel there is a number; "Ref. 797"

 

So, my questions are;

- Anybody any idea which movement this could be and made by whom? (a Cortebert??)

- If the movement stays unknown, what is the best way forward, if there is any?

Hope to hear .......

 

 

 

[praezis]

Tavannes = Cyma 797

Staff Ronda 2312

Frank

[KarlvonKoln]

Frank is the man!

Here's where you can get one:

https://www.balancestaffs.com/product.php?ronda-number=2312

[Endeavor]

@praezis & @KarlvonKoln My goodness ! I didn't expect that ....... such a fast solution which seemed to me a pretty insurmountable problem.

If I can't get anywhere with the seller on "Kleinanzeigen", who is so far wearing his Teflon suit, I will go after a Ronda 2312 staff. The reference number under the balance wheel seemed to have, together with your splendid help, saved my *ss

Thanks a lot for the quick help ...... Tonight I will probably sleep a whole lot better!

BTW; Now knowing that it's a CYMA 797 movement, Bidfun-db refers to the balance staff as U1702. If I were to stumble over a staff with a U1702 reference, would that be okay too?

[mikepilk]

57 minutes ago, KarlvonKoln said:

Frank is the man!

Here's where you can get one:

https://www.balancestaffs.com/product.php?ronda-number=2312

If you search ebay, you can find them much cheaper - and Cousins have them for about £10 for a pack of 3 !

I don't know what the balance staff reference numbers are on Ranfft, anyone ?

Edited February 24, 2023 by mikepilk

[Endeavor]

37 minutes ago, mikepilk said:

If you search ebay, you can find them much cheaper - and Cousins have them for about £10 for a pack of 3 !

Today I attended a funeral, received a watch with a broken pivot and even though it's already dark here in DK, the sun starts to shine brighter and brighter

Indeed, CousinsUK, 3x Ronda 2312 staffs for £8.95 ex.VAT.

Just to double check @praezis, where did you find CYMA 797 has a Ronda 2312?

Edited February 24, 2023 by Endeavor

[mikepilk]

I can confirm it's 2312 - Cousins also have the Ronda balance staff documents in PDF format if you do a search. A pack of 3 gives you more goes should it go wrong 

Changing staffs is pretty straightforward with a staking set. The hardest part is getting the feel of how hard to hit the hammer. There's a good explanation in Fried's "The Watch Repairers Manual"

Good luck

PS Do you have a means of removing the staff? I have a K&D staff extractor. Works a treat, but frowned on by many - just don't tell @praezis  

Edited February 24, 2023 by mikepilk

[Endeavor]

54 minutes ago, mikepilk said:

PS Do you have a means of removing the staff?

No, I don't and I just read a lengthy discussion about it here on WRT, seems another can of worms 

I've to investigate & learn. I do have a jeweling tool and a staking set. A lathe is not an option, so it has to be the next best. What that will be, I've to investigate.

What about a roller-remover, do these Bergeon work okay?

Once I bought the same model at CousinsUK, but the cheap India version; they are total crap. Are these Bergeon's any better or is there a another (cheap) alternative?

[LittleWatchShop]

Interesting saga. I have one of those roller removers. I don't think I have ever made it work...didn't try very hard. I use a Rex roller remover exclusively.

[VWatchie]

2 hours ago, Endeavor said:

What about a roller-remover, do these Bergeon work okay?

I have one of those (of course! )

The first time I tried it I snapped the staff. Not that it mattered much but it was still a "traumatic experience" 

I'd suggest a "Roller Remover with Punches, Bergeon 30070". Cousins has it for £61.55. Or, a "Bergeon Platax No. 2677" which sometimes surfaces on eBay.  It can be used both to remove the roller and punch out the old staff. Frowned upon (like the K&D staff extractor) but works great in my opinion and I've made a guide for it here on WRT named "How to remove a balance staff using the Bergeon Platax tool No. 2677" which also includes a video in which Mark is using it to remove the staff from a vintage 1940's Cyma. If it's good enough for Mark, it's good enough for me (Yes, I'm aware of the risks!). The problem is its price and that it has been discontinued (perhaps not considered safe by Bergeon!?). A used copy on eBay is usually around $500 to $1000.

Anyway, I guess you can punch out the staff using your staking set, but there's a real risk the punch will follow through into the balance wheel staff hole, expanding the hole or even destroying the balance wheel. I wouldn't dare to (I think...) but there are people doing it like in the video linked in this post "Removing a balance staff. Should this video come with a disclaimer?" where I question the practice.

It's a beautiful pocket watch and in my opinion well worth restoring!

[JohnFrum]

Archer on Watchuseek suggests using alum solution to remove the balance staff.  

Apparently Rolex has a special pusher and anvil for the Horia tool to break their rivets. 

As regards roller removal, the AliExpress balance tool works just fine. Has 4 notches for rollers.

 

Edited February 24, 2023 by JohnFrum

[rehajm]

I like the little roller remover. There was free one floating around in the bottom of my staking set when I purchased it. I about shot my eye out the first time I used it but once you get a feel for the pressure it works fine…

To remove the balance staff use a jeweling tool if you have one instead of the staking set- easy peasey…

[Endeavor]

7 hours ago, VWatchie said:

The first time I tried it I snapped the staff

I had the exact same experience with the Indian version. Luckily it was a test on a scrap balance. I blamed it on the poor quality (even CousinsUK gives you a clear warning: " Due to the manufacturers finishing the actual roller removing jaws may need filing and burnishing to suit"). The tool went straight into the bin.

I was hoping that the Bergeon was better, but seemingly not.

7 hours ago, VWatchie said:

I'd suggest a "Roller Remover with Punches, Bergeon 30070".

Trying to reduce the cost, I was wondering whether I could construct something myself with just the Jaw Plate R48647. Currently out of stock, I presume due to that others had the same idea, not because these things do snap off?

7 hours ago, VWatchie said:

I guess you can punch out the staff using your staking set

I like the idea of using what I already have. Even though I really would like to repair this movement (learning curve) and I did paid enough for it (€120, certainly way too much for a broken PW) but any investment has to be within reason. A Bergeon Platax tool, same as a lathe, is not an option.

7 hours ago, JohnFrum said:

As regards roller removal, the AliExpress balance tool works just fine. Has 4 notches for rollers.

AliExpress is tricky here in DK. When shipped from outside the EU, due to ransoms, double the price 

4 hours ago, rehajm said:

To remove the balance staff use a jeweling tool if you have one instead of the staking set- easy peasey…

I do have a jeweling tool and if it were that easy-peasy, then I wonder why we have all these lengthy discussions "how to extract a balance staff safely" here on WRT? I've to investigate how that would safely work? It would be nice though ......

Edited February 25, 2023 by Endeavor

[mikepilk]

1 hour ago, Endeavor said:

I had the exact same experience with the Indian version. Luckily it was a test on a scrap balance. I blamed it on the poor quality (even CousinsUK gives you a clear warning: " Due to the manufacturers finishing the actual roller removing jaws may need filing and burnishing to suit"). The tool went straight into the bin.

I was hoping that the Bergeon was better, but seemingly not.

I had the same experience - the cheap tool was useless. I bought the Bergeon tool which works perfectly. I can recommend it.

The K&D tools can often be found on ebay 

[rehajm]

4 hours ago, Endeavor said:

I do have a jeweling tool and if it were that easy-peasy, then I wonder why we have all these lengthy discussions "how to extract a balance staff safely" here on WRT? I've to investigate how that would safely work? It would be nice though ..

…because those discussions are what happens here- everyone is constructive and sharing their training, experiences, methods and there’s often multiple ways to accomplish things…

…and here’s some video of using the horia. I’ve done this several times including for an old Rolex but as others have mentioned there are special rolex bits, too. Good luck….

 

[Neverenoughwatches]

17 hours ago, mikepilk said:

If you search ebay, you can find them much cheaper - and Cousins have them for about £10 for a pack of 3 !

I don't know what the balance staff reference numbers are on Ranfft, anyone ?

I looked into the ranfft part references a while back. I could be wrong but i think its relates to flume part codes.

17 hours ago, Endeavor said:

@praezis & @KarlvonKoln My goodness ! I didn't expect that ....... such a fast solution which seemed to me a pretty insurmountable problem.

If I can't get anywhere with the seller on "Kleinanzeigen", who is so far wearing his Teflon suit, I will go after a Ronda 2312 staff. The reference number under the balance wheel seemed to have, together with your splendid help, saved my *ss

Thanks a lot for the quick help ...... Tonight I will probably sleep a whole lot better!

BTW; Now knowing that it's a CYMA 797 movement, Bidfun-db refers to the balance staff as U1702. If I were to stumble over a staff with a U1702 reference, would that be okay too?

Tavannes and Cyma had a strong connection using the same movements. Tavannes being a joint venture between henri sandoz and the schwob family. Sandoz being the brains behind design and manufacturing and schwob freres marketing and sales providing connections from previous ventures. Setting up business in Tavannes hence the company name. The Cyma brand came from Schwob and apparently was a seperate company developed for sales. Names on dials will include Tavannes Cyma and also Tacy ( which is the two names part joined .

[Endeavor]

@rehajm: thanks for the video and I like it

I do fully appreciate the points made by @nickelsilver, @praezis and other very competent members, being that of a deformed staff pushed through the balance wheel hole which will most likely causes an enlargement of the hole. But not having the means and the luxury of having a lathe, I've got to go for the next best method. Being a 1930's balance staff, let's hope that CYMA didn't use the best of the best materials ....

I also like that in the video he uses the Bergeon 2810 roller remover, a tool easy within my reach and which, also according to @mikepilk, seems to work fine. I do have a collection of scrap balances c/w roller tables to train on, to hopefully avoid snapping the staff in two, like I had with the cheap Indian roller remover version.

I do have a complete Seitz (hand-lever) jeweling set and a complete Boley staking tool. The Seitz jeweling tool has ø1mm, ø1.5mm, ø2.0mm and ø2.5mm perforated stakes. It doesn't seem that CousinsUK has any stake-sizes in between. CousinsUK next size up is a 4mm perforated stake, but currently out of stock ...... that size seems to me overdone too.

I've seen another video, using the same method with perhaps more appropriate stake-sizes (or "stumps" as he calls them). For removing the Roller he uses two razor-blades, as from the 09:00 min mark .... Currently I think I'll prefer the Bergeon roller remover tool.

But apart from that, it's about the same method as in the video Rehajm referred to;

For me, both are interesting video's and something I could potentially pull off.

Edited February 25, 2023 by Endeavor

[praezis]

The U... staff numbers are the Flume (German wholesaler) numbers.

The Bergeon Bradux works fine with wrist- and more modern pocketwatches. It can bend the roller frighteningly if it sits extremely tight. Correctly used, I dont see how it can snap the staff. I used it often, but now prefer the lathe (again the lathe replaces a thousand special tools!). 
Of course this and the Indian copy are worlds apart (copied but no idea of its task and how to use it).

Frank

[LittleWatchShop]

2 hours ago, praezis said:

lathe replaces a thousand special tools!

I love my lathe(s)!!!

[mikepilk]

3 hours ago, praezis said:

The U... staff numbers are the Flume (German wholesaler) numbers.

The Bergeon Bradux works fine with wrist- and more modern pocketwatches. It can bend the roller frighteningly if it sits extremely tight. Correctly used, I dont see how it can snap the staff. I used it often, but now prefer the lathe (again the lathe replaces a thousand special tools!). 
Of course this and the Indian copy are worlds apart (copied but no idea of its task and how to use it).

Frank

Good point about bending the roller - they can be very soft. I trashed one trying to close the hole - gave it the gentlest of taps and squished it 

You have to check that the blades of the Bergeon tool are right at the base of the roller and pushing against the top of the staff shoulder. The last time I used my cheapo tool, though I'd filed the blades, they were still too fat and pushed against the balance arms instead of the staff shoulder, resulting in a staff removal (even worse method than the K&D tool )

[Endeavor]

I think I have enough answers to hopefully rescue my newly acquired pocket-watch.

The broken balance staff pivot was a bit of an unpleasant surprise, but it presented new challenges too. Every disadvantage has its advantages

So, thank you all for your swift & excellent help !

I hope I'll be able to report some good news in the not so far future

 

Edited February 26, 2023 by Endeavor

[Endeavor]

The tale sits in the tail !

I started disassembling the movement and it looked untouched, apart from the fact that it was nicely oiled. Removing the main-spring and the innocent sellers tale revealed itself 

A well oiled but repaired mainspring;

I guess during the service / repair a balance pivot broke and the watch was "dumped".

So far for "I never noticed, I'm not a watchmaker"

Apart from the broken pivot and a repaired main-spring, the movement looks excellent.

 

[Endeavor]

Booked a kind of suc6

It wasn't simple and the learning curve has been huge.

The newly ordered balance staff from CousinsUK were perfect. Fitting the balance wheel, for the first time I've done this endeavour, was a bit of a challenge.

Tapping carefully with a 40gram hammer on my wooden desk didn't yield any suc6; nothing appeared to happen. Bigger hammer, not much change. Most likely this due to the "spring action" from the rubber-mat and the wooden desk. It wasn't until I took the staking-set outside onto the stone pavement that the rivet started to deform. The initial test with the tweezers, holding the staff and turning the wheel, looked good; both were turning.

Next was the installment of the in two parts roller-table and safety roller (https://www.watchrepairtalk.com/topic/25761-two-parts-or-a-split-roller-table/#comment-212114

This was a real challenge as the roller-table, pressed fully down, was still able to rotate on the staff. The safety roller had to be pushed down really hard to "lock" the roller-table.

Checking the combination again, I noticed that the balance staff could still rotate in the balance-wheel; it need some force, but it could still move. Since the last thing I wanted was to take the roller-table and safety roller back off, to give the staff-rivet a few more taps, I decided to leave it "as-is".

The balance wheel proved to be nearly true on the staff, way too little to take the risk of correcting until fully perfect. The wheel has a hardly noticeable wobble.

With the chance of rotating the staff, correcting the beat error meant lifting the hairspring collet off the staff each and every time a correction had to be made. Finally I got the beat-error within reason, not perfect, but it has to do.

I couldn't find the lift-angle of a CYMA 797, but with about a 180 degrees amplitude I determined that the lift-angle had to be somewhere between 40 - 42 degrees.

Anyhow, here are the results of my first balance staff change-out with a 40 degrees lift-angle & a freshly serviced movement:

The other two vertical positions were about the same. Perhaps in time the amplitude in the vertical positions will increase a bit.

Perhaps everything is not super-duper, but it could have been a whole lot worse, i.e. the watch could have been lost.

I guess for a nearly 100 years old pocket watch, it will run just fine

Next to that the watch is "saved", I learned a horrendous lot, how to do and even more important, how not to do things. Hopefully next time a bit better job

Thanks all for your contribution and help !

 

Edited March 12, 2023 by Endeavor

[mikepilk]

Well done. Changing your first staff is a bit scary. I started on Waltham pocket watches which have push-fit staffs. Easier for a beginner.

My advice (for what it's worth) - Once it's running OK, take the lessons learnt, and move on. Don't keep tinkering looking for perfection - you can mess things up.

When you are more proficient, you can always re-do it at a later date. I've plenty of watches that I first serviced years ago and struggled to get running well, but now when I re-service them, I've no problem. 

BTW the beat error is more than adequate. For watches where you have to rotate the hairspring, I take anything within about 2ms as OK.

[Endeavor]

3 hours ago, mikepilk said:

My advice (for what it's worth) - Once it's running OK, take the lessons learnt, and move on. Don't keep tinkering looking for perfection - you can mess things up.

@mikepilk Yes, I came to that same conclusion quite some time ago. In the old days they didn't worry too much about amplitude either. All a pocket watch has to do is to push hands around for 24hrs, no date, no chronograph, just the hands.

I'm pretty sure that the watch will run well within 30 seconds a day, if not much better.

One has to judge the risk versus the benefit, and currently IMHO there is nothing to be gained. I don't think I will re-visit the watch to make improvement ..... if there is anything to be gained at all!

With this experience under my belt, I'll move on to my next Endeavour !

Oh, forgot to say, I added some tools on my wish list. On the look out when they pop-up at a bargain price

Edited March 12, 2023 by Endeavor