hairspring vibrating tool

[syfre]

Hello guys,

An attempt to make a low cost hairspring vibrating tool :

Prove of concept :

The hairspring (here it's a 18s balance) is clamp in a crocodile clip which has been grinded to be as fine as possible, a laser beam is set so that the beam is cut by the balance arm. The photo diode (from an old pc mouse ) is en-capsuled in a little housing to avoid parasite light (from what i thing to be an old TO3 transistor spacer found in my spare screws box).

The IC is just a simple op amp acting as a comparator, the led on the output is used to visualize the that the laser beam is on the detector.

First measure on scope :

Doing some simple math show that an error of 0.1 ms on the measured value (which is 400 ms for 18000 bph) correspond to an error of 21.5 seconds / day. At that time base setting my scope has a resolution of 4 ms !

I switched to an Arduino based measuring system :

I used an existing Arduino module based on a cheap stm32  and add a led (indispensable to adjust the beam) and the power output for the laser. The comparator is no more required as the stm32 has schmitt trigger inputs. The soft is triggered by the touch screen and accumulate a couple of measures in a circular buffer to compute an average value. This permits to eliminate aberrant measures that you can have when the balance starts to swing.

 Detail of the crocodile clip :

In conclusion this is little tool (cost me only the plexyglass sheet, around $1.5)  could be useful to match a new hairspring on an existing balance. The measures are relatively simple to do with a good consistency and surprisingly the croco clip do the job and you can get the balance swing for tens of second on the plexy. You need a resolution of 0.05 ms to be at 10 s/d and probably calibrate your measuring device. The main difficulty was to adjust the position of the laser beam.

Hope this can give you some ideas.

Regards

 

 

 

 

 

 

[Deggsie]

I love the ingenuity behind this, especially the fact it is manufactured from relatively low cost components. Would I be right in thinking that the initial angular excitation is made by rapidly displacing the whole apparatus through a small angle, or have I missed a part of the rig?


Sent from my iPhone using Tapatalk

[vinn3]

why vibrate  a spring?

[teegee]

Very nice! This has been on my low-priority to-do list as well, but I didn't get much further than thinking about how to do the actual balance frequency pickup. I play with stm32/stm8/arduino stuff as well.

I thought about building an old-school one, but they are just too impractical as they only work at a single bph.

Have you ever used the legacy version? I've never replaced a balance spring, only fixed them. Sadly enough, sometimes because I warped it myself in a clumsy moment. The smaller the hairspring, the easier it is to damage and the harder it is to fix.

Your alligator clip looks much too strong to safely hold the spring. I assume you've modified it?

 

[oldhippy]

If the clip fails to grip the hairspring and it drops onto the plexyglass you could end up with a broken balance staff. That clip looks as if it might bend the hairspring so it could be out of shape.

 

Nice try but I think you need to modify it. Why do you need such a device? Are you intending to make your own balance?

[praezis]

Hi syfre,

I like your prototypes and your spirit of research.

Who ever had to make a flat or a Breguet hairspring (happens now and then in my shop), knows why you need such a device.

Years ago I made my own device as I did not like the traditional boxes that can test one beat rate only and are ridiculous expensive, very similar to your setup:

 

Advantage: box has a built-in 3 V battery that lasts for years (or one month if running permanently).

Frank

Edited February 12, 2018 by praezis

[Tmuir]

Nice, I have thought about doing something similar as I have a couple of spare Raspberry Pis with displays and a couple of laser diodes lying around, but on the list of tools I still need to make a hairspring vibrator is pretty far down on the list.

For pure tool porn you can't beat the look of the old fashioned hairspring vibrators though.

[measuretwice]

27 minutes ago, Tmuir said:

For pure tool porn you can't beat the look of the old fashioned hairspring vibrators though.

Agreed, like the one in the photo above.  I can see how details like the two rack and pinions would make it a pleasure to use, but things like that take a lot of time to make.

[syfre]

14 hours ago, teegee said:

Your alligator clip looks much too strong to safely hold the spring. I assume you've modified it?

Yes, the alligator clip has been modified , it works much better than i thought, but i tried pocket watch hairspring only. Also i used an old croco clip which was originally shaped differently than the chinese ones you can find on the bay.

 

 

14 hours ago, teegee said:

 

 

[Deggsie]

why vibrate  a spring?

Hi vinn. The objective is to measure and validate the dynamic frequency of the balance / hair spring as a system, therefore it needs to be set into motion first. There are some good videos of the traditional empirical method on the BHI website. The system is excited by pushing and releasing a lever then comparing angular displacement over a fixed time. It’s rather tedious looking, but the above apparatus is ingenious


Sent from my iPhone using Tapatalk

[Deggsie]

Hi syfre,
I like your prototypes and your spirit of research.
Who ever had to make a flat or a Breguet hairspring (happens now and then in my shop), knows why you need such a device.
Years ago I made my own device as I did not like the traditional boxes that can test one beat rate only and are ridiculous expensive, very similar to your setup:

 
Advantage: box has a built-in 3 V battery that lasts for years (or one month if running permanently).
Frank

Nice adaptation of the luthy-Hirt oscillator.


Sent from my iPhone using Tapatalk

[henry30]

Hello

I am French, I am not an electronics engineer, but passionate about old watches.

I'm very interested in your two montages. Could you give me all the instructions to make this vibrator.

Kind regards

[nickelsilver]

Praezis actually makes these for a very reasonable price- I'm glad you posted, I've been meaning to buy one and it slipped through the cracks, will order now!

 

If you send him a message he can send the info and user manual, it looks like a killer tool. Not only are the master balances rare to find (in odd beats especially), they are prone to damage and drifting in precision. I only do a hairspring every few months but I know this will pay for itself in zero time (pun intended).

[Nucejoe]

No first attempt results in a fully developed prototype.

I need the tool too. 

I wish you success, Syfre.

 

[vinn3]

On ‎2‎/‎12‎/‎2018 at 12:02 PM, Deggsie said:

Hi vinn. The objective is to measure and validate the dynamic frequency of the balance / hair spring as a system, therefore it needs to be set into motion first. There are some good videos of the traditional empirical method on the BHI website. The system is excited by pushing and releasing a lever then comparing angular displacement over a fixed time. It’s rather tedious looking, but the above apparatus is ingenious


Sent from my iPhone using Tapatalk

   I should have known,   I thought it was a horse at Long  Acres.     vin

[henry30]

 

Another interesting homemade product :

https://www.pascalchour.fr/mesures/chour_rm1.htm

https://www.pascalchour.fr/mesures/chour_rm3.htm

[JohnR725]

Digital hairspring vibrating tool / Heilahduslukulaskuri

https://youtu.be/htckrH3ae54

 

[henry30]

This is the tool

http://www.rataspari.com/index.php/products/hairspring-tool

EUR 3500 (excl. taxes)

[m1ks]

18 minutes ago, henry30 said:

This is the tool

http://www.rataspari.com/index.php/products/hairspring-tool

EUR 3500 (excl. taxes)

Hey! It does come with basic tweezers though.

It looks great. I just don't need one that badly.

[nickelsilver]

I've seen the Finnish tool firsthand and it is an excellently made piece of equipment. As I already have a regular Luthy tool, I'd rather go for Frank's optical platform that fits it with the software; the Luthy tools can be found for a few hundred bucks. I think the Finnish tool would be well suited for small boutique makers doing small series custom watches; the next step from there is the Greiner system which I think starts around 20k...