Beha D202

[rossjackson01]

Hello. I'm on my first assignment. Beha with a D202 movement. I've disassembled, cleaned. Enjoyed myself. However I am aware that this is a 'not ever in a chance will it work' project. It's just for my own experience.

I friend has asked me to look at his fathers watch, Swapped for a cup of coffee granules in Berlin 1950's. It has been looked at by someone who has attempted to get it going my rotating the balance. Hairspring is well and truly knackered. Movement screws missing. Can't believe the damage done by and 'expert'.

Regarding hairsprings? Are they specific for a balance. Is it possible to obtain a similar hairspring and fit it?

I have taken photographs, but they are poor.

 

Edited January 18, 2023 by rossjackson01

[dadistic]

It's not generally possible to replace just the hairspring. The hairspring and balance wheel are "tuned" together.  I think in this instance, a parts donor movement would be the way to go. 

It may be possible to put that hairspring right, but it is a truly delicate process, and something you may or may not want to try. 

@JohnR725 recently posted the link to this video,  and Henry Fried makes it look easy. He was, however, a true expert. 

[rossjackson01]

Thank you. Saw the video. Fabulous.  Maybe in couple of years will I have the expertise. Ah well.

[JohnR725]

12 minutes ago, dadistic said:

He was, however, a true expert.

Yes he definitely was a very interesting person. I always think every time I hear his name I can remember the last conversations I had with him at a national meeting in Chicago.

14 minutes ago, dadistic said:

It's not generally possible to replace just the hairspring.

That's a partially correct answer. If it's a flat hairspring that hairspring was vibrated for that specific balance wheel. Silly in general cannot swap flat hairsprings which is why there never listed as a spare part on a parts list.

If you have an over coil hairspring the over coil hairsprings typically are premade to very exacting specifications. Then the balance wheel is matched to the hairspring but the factory as a infinite supply of screws and conceivably custom makes the screws to exactly fit.

But over coil hairsprings are listed on parts lists along with the associated timing screws that you need to match them to a balance wheel.

Your hairspring appears to be flat. It does appear perhaps that those are timing screws but I'm not sure that they actually come off and I'm guessing in real life the best thing to do would be balance complete because matching a hairspring to your balance wheel is going to be very challenging. Or in general almost impossible.

[Vinito]

I can't help but notice the elephant in the room.
If the existing hairspring is well and truly knackered as you say, then there is zero chance of doing damage to it by taking however many sessions you can stand and working on straightening it out. It won't hurt, and you'll probably gain significant experience, and the chances are heavily in your favor that you can make it better than it useta was and come out the other side with a bit of confidence boost even if you don't actually succeed.

Also, this conversation inspires a question: I constantly hear that a hairspring and balance are a package deal and one just needs to find a replacement. OK, maybe it's not trivial at all, but it's not like these paired up assemblies drop from the floating fairy dust left over from unicorn farts These are made by human people things. If you can get an accurate measurement of the spring wire cross section and number of winds, then it seems like a courageous feller could jump in with both feet and accomplish the task somehow. Why should watchmaking include all these many skills and tasks except for, dog forbid, replacing the magic hairspring? Honest question.

Edited January 19, 2023 by Vinito

[JohnFrum]

2 hours ago, Vinito said:

Why should watchmaking include all these many skills and tasks except for, dog forbid, replacing the magic hairspring? Honest question.

See Fried’s book ‘Bench Practices for Watch Repairers’. 
 

And this web site with great photos of the process. http://www.bobinchak.com/watchmaking/2017/4/26/hairspring-week-vibrating-the-hairspring?format=amp

Edited January 19, 2023 by JohnFrum

[praezis]

13 hours ago, rossjackson01 said:

with a D202 movement.

Sorry, no idea what this is. If you specify the calibre, we could look up our inventory for a balance.

Frank

[nickelsilver]

11 hours ago, Vinito said:

 Why should watchmaking include all these many skills and tasks except for, dog forbid, replacing the magic hairspring? Honest question.

Watchmaking schools still teach hairspring vibrating, some more than others. The skill built doing dozens of them under expert instruction translates to everyday hairspring truing very well. The big issue if wanting to replace a spring is sourcing them. Way back in the day you could buy a packet of graded hairsprings from a supplier, in steel or more modern alloy. Today there are a few limited sources, usually with a small or oddball range of sizes. The manufacturers, Nivarox being the big one, don't want to sell a few springs; they want to sell thousands. You can usually negotiate for perhaps 100pcs, of one size, so there's that (but they aren't cheap). So one either spends time and money slowly collecting an array of different CGS numbers (the grading system for hairsprings), in both steel and Nivarox type alloys- though- often the steel ones will be graded in an older system!- and hopefully have some that might correspond to a given balance.

 

Then, really, you need a Luthy tool to count the spring, the link in JohnFrum's post above shows it well. These have reference platforms for specific frequencies, 18,000 being the most common. A different platform is needed for each different frequency (or- Frank Praezis above can supply an electronic platform that does any frequency!). Springs can be counted without the Luthy tool, but it's a miserable process.

 

You can usually reuse the original collet and stud if replacing a mangled spring, but it's nice to have an assortment of them as sometimes you may have no spring at all, or the collet is split, etc.- and there are many different sizes, so again, a lot of searching and buying and hoping.

 

Back when Fried and others were writing their books, let's say the first half of the 20th century, modern manufacturing methods had made replacement parts plentiful and affordable, so a lot of manual skills that were focused on in schools or apprenticeships faded a bit. But there were still many older watches, older being what we would call antique now, where no material is available at all. Thus the chapters on vibrating springs, or repairing fusee chains, and so forth.

 

Attached is a list of common CGS numbers and the approximate balance size they might correspond to, and a convienient conversion to the old system.

Edited January 19, 2023 by nickelsilver

[JohnR725]

11 minutes ago, nickelsilver said:

older being what we would call antique now, where no material is available at all.

Actually even way back then I guess depending upon the way back when was hairsprings were still available. No skill required other than to send it off and a new one would come back. I remember when I was in school we did that we needed a hairspring for something Off it went and then it came back brand-new.

 

[rossjackson01]

Taking the bull by the horns. Can't lose anything.  This it. Was wrapped around the stub. I have disassembled, cleaned, assembled, lubricated the watch. Everything is fine. Final thing is .... spring eternal.

Movement is Durowe D202

Great fun this hobby. 

Edited January 19, 2023 by rossjackson01
Movement name

[watchweasol]

Hi Ross   its not too bad but bad enough, as said nothing to loose and everything to gain, just do it slowly and quit when tired only to pick it up again. Done by degrees.  dont bend it use a stroking action to re form the spring.    good luck

[rossjackson01]

3 hours ago, praezis said:

Sorry, no idea what this is. If you specify the calibre, we could look up our inventory for a balance.

Frank

Yes please. If it's possible to check Durowe D202

[rossjackson01]

Update on balance hairspring straightening.

Tried to do the straightening using magnifying glasses. Too awkward. Duh! Use the digital microscope your bride got you for Christmas. Placed spring on paper and then on staking block. Better for vision. Metal block makes it awkward to differentiate hairspring and metal background. 

Using two tweezers. Probably incorrectly, but watching and learning from Marks video I set about the repair. Gentle hold, gentle stoke. After 1/2 an hour, it's a little better, but i''m getting heavy tweezered. Almost went to bend it. Take a break. 

As can be seen it is a little better, but long way to go. 

 

 

 

Edited January 21, 2023 by rossjackson01
too many photographs. Spelling

[JohnFrum]

A good start on that terminal curve. I’m struggling with this myself. Destroyed three practice springs. Have managed to get one in a decent condition. This really requires patience.  

[rossjackson01]

Yes. Mark is right when he intimates 'practice, practice and more practice'. Some good videos on YouTube. Can recommend this cheap digital microscope. £42.50 inc VAT and free postage. 7" display 

 

[Nucejoe]

 Detach the hairspring from the balance, pin the collet on white sheet of paper/ cardborad, to have much more control over the peice. 

Shaping a perfect terminal curve is challanging, call it good as long as the coil is centered and oscilator runs alright. 

Rgds

Your oscilator would inevitably  be out of beat when you sort out the coil anyway, another task to adjust it in beat.

[rossjackson01]

9 minutes ago, Nucejoe said:

 Detach the hairspring from the balance, pin the collet on white sheet of paper/ cardborad, to have much more control over the peice. 

Shaping a perfect terminal curve is challanging, call it good as long as the coil is centered and oscilator runs alright. 

Rgds

Your oscilator would inevitably  be out of beat when you sort out the coil anyway, another task to adjust it in beat.

Thank you Nucejoe. Good advice. However I have not yet got the skill to detach or to centre. I have ordered another movement to be able to complete the restore. This is my first practice at this sub atomic level. I do not expect it to ever work correctly. But it is good fun. 

Edited January 21, 2023 by rossjackson01
spelling

[watchweasol]

Ross you have the paitence you just need to practice the skill bit and back off when tired or tweezerd,  have a beer and come back another day/ Its all about attitude, and as Joe said work on a piece of white carboard,     all the best.

[rossjackson01]

1 hour ago, watchweasol said:

Ross you have the paitence you just need to practice the skill bit and back off when tired or tweezerd,  have a beer and come back another day/ Its all about attitude, and as Joe said work on a piece of white carboard,     all the best.

Beer? Hic. Oip. Burp! 

[praezis]

practice, practice will be just one needed component here. Without a curve tweezers I cannot imagine to reform this kind of damage 

No balance Durowe 202 in stock, I am sorry. You may find it as Durowe 10 1/2, 410 or 412, too.

Frank

[JohnR725]

10 hours ago, rossjackson01 said:

Yes. Mark is right when he intimates 'practice, practice and more practice'

This is why I relate watch repair to an similar to being coming a doctor. Doctors always say they're practicing and were doing the same thing all of us are practicing every day we work on a watch. 

[rossjackson01]

21 hours ago, praezis said:

 

No balance Durowe 202 in stock, I am sorry. You may find it as Durowe 10 1/2, 410 or 412, too.

Frank

 

Thank you for looking. I have been able to source a d202 movement from Germany. Like you, the company has been most helpful.  The balance looks the same, but the configuration on the train wheels looks different. Will keep you all updated on receipt.  

Regards to all.

Ross

Edited January 22, 2023 by rossjackson01