How to make a watch 10 min/day faster (or slower)?

[rappeleur]

Hello!

 

Up front: I know that usually one takes a new balance (or whatever spare part) and makes a proper repair. BUT, this is more of a general question... please correct me if I am wrong!

 

The speed of a watch is beside many other things dependent on the length of the balance spring. The longer the spring, the slower the watch. (?) Also the weight of the balance is important. The heavier, the slower.

 

Given the case, I have a (scrap) watch with no balance spring and no idea, how the correct one looks like. But I have a enormous amount of old springs for repair. I can now pick one, put them on and see how it is "performing", meaning: keeping time. When the watch is gaining about 5-10 minutes a day: is there a way to set the correct speed with the actual spring or is this quite impossible?

 

For example: how much (in min/day) is another round of the spring? Or say, an extra 1 cm of length? How much can be adjusted screwing the little balance screws in or out from the center? Or is oiling the pallet fork pivot slowing the movement also a bit?

 

Sorry for asking such noobie questions, but this adds a lot to my understanding

 

Thanks!

Edited March 12, 2018 by rappeleur

[Chopin]

It's not impossible but it would take a lot of time to get it right or just sheer dumb luck.

You're supposed to have the CORRECT hairspring for the CORRECT movement. That means the CORRECT balance and so on.

It's not as easy as picking any hairspring that looks like it fits and then you mount it and it'll keep time well. Sadly.

[rogart63]

As an example i have tried to mount a MST 317 balance on a Eterna 629 movement. I couldn't find a balance for this movement so i have been tinkering a little to see if i could at least get it to work decent. Sure it works but not any good. It's gaining about 15 min a day. Has a very low amplitude. I can probabaly get it to work better but i need a longer balance staff. The MST 317 is to low on so it hitting the pallet bridge when it's dial down. So only works okay when dial up. One day maybe. 

[jdrichard]

Hello!
 
Up front: I know that usually one takes a new balance (or whatever spare part) and makes a proper repair. BUT, this is more of a general question... please correct me if I am wrong!
 
The speed of a watch is beside many other things dependent on the length of the balance spring. The longer the spring, the slower the watch. (?) Also the weight of the balance is important. The heavier, the slower.
 
Given the case, I have a (scrap) watch with no balance spring and no idea, how the correct one looks like. But I have a enormous amount of old springs for repair. I can now pick one, put them on and see how it is "performing", meaning: keeping time. When the watch is gaining about 5-10 minutes a day: is there a way to set the correct speed with the actual spring or is this quite impossible?
 
For example: how much (in min/day) is another round of the spring? Or say, an extra 1 cm of length? How much can be adjusted screwing the little balance screws in or out from the center? Or is oiling the pallet fork pivot slowing the movement also a bit?
 
Sorry for asking such noobie questions, but this adds a lot to my understanding [emoji4]
 
Thanks!

Need to time the spring vibrations to get 18000 beat rate. I’ll get back with more detail, but you hang it over another movement and give it a wrist twist while hold in vertical with tweezers and then count how many full vibrations and do the math. Then you know if it is running fast or slow based on where you are holding the spring with the tweezers. The adjust the tweezers to take up or let go spring length. Once the count is correct, that is where you need to place the hairspring stud.


Sent from my iPhone using Tapatalk Pro

[rappeleur]

After a bit of tinkering around with this issue...: I am now able to change a balance spring within 3-4 minutes  (I practised it some dozen times last day). 

Conclusio: I tried with a most similar spring, which was obviously much too weak, nearly not swinging at all when mounted. The other one was "stiffer" but much too slow. I then shortened the length half a revolution bit by bit. After having cut some 1 - 1,5 revolutions the balance spring was about to make the watch quite good keeping time. Only thing I encountered: when setting time on the timegrapher it is a quite large change when moving the regulator only the smallest bit.

 

See picture: agreed, the beat error is way off, maybe I’ll correct that in another try... but for the other values, hey, that is a scrapt watch, which maybe hasn’t only seen the sunniest times the last 80 years!

 

 

 

 

 

[JohnR725]

On 3/12/2018 at 12:25 PM, rappeleur said:

The speed of a watch is beside many other things dependent on the length of the balance spring. The longer the spring, the slower the watch. (?) Also the weight of the balance is important. The heavier, the slower.

Generally what you said is true except it's not entirely the weight of the balance wheel is also the physical size characteristics. Simplistically it gets very complicated. For instance Sometime on American pocket watches you get some bizarre timing or extremely fast or slow just because the arms are not where there supposed to be. Somebody's either bent them in or out or some combination totally screws up timekeeping. So the balance wheel has to be perfectly round. So moving arms in and out doesn't change the weight of the balance wheel the same as moving mean time screws in and out affects timekeeping but the weight of the balance doesn't change.

 

On 3/12/2018 at 12:25 PM, rappeleur said:

Given the case, I have a (scrap) watch with no balance spring and no idea, how the correct one looks like. But I have a enormous amount of old springs for repair. I can now pick one, put them on and see how it is "performing", meaning: keeping time. When the watch is gaining about 5-10 minutes a day: is there a way to set the correct speed with the actual spring or is this quite impossible?

Their other physical characteristics for the hairspring beyond frequency. Like for instance they hairspring is a spring the energy stored in the hairspring is used to unlock the escapement. You go to dramatic the hairspring won't have the proper characteristics the watch will not run correctly.

Then I've attached a PDF the section of the book which I have the description listed below. So if we were discussing blank raw hairsprings there is a procedure to figure out what the correct spring size is. But that totally flies out the window because you have a ready-made spring with zero known characteristics other than it's a spring. But I'm still attaching the PDF so you can see how it's supposed to be done if we had New hairsprings.

Or simplistically you're stuck with trial and error. Then thinking about error your Timing machine 9.9 ms has been discussed somewhere else the Chinese machines have problems beyond a certain range. So numerically they'll show stuff but it may not be correct so you visually have to put the watch in beat first. Then the published specs on the timing machine are 999 seconds fast or slow that works out to A little over 16 minutes. If you owe beyond that I have zero idea what the timing machine at least the Chinese is going to show you. So a better approach for timing machine to do this sort of thing is get a witschi machine that has frequency or clock persons timing machine. Both of them measure beats per hour which is really nice when you're totally out of range and the timing machine is confused by swapping hairsprings or other assorted strange problems

Then you are timing machine image looks like a sine wave? Typically sine waves are the results of the magnetic field or specifically magnetized watch.

Then the watch adjustment book deceptively simple title really interesting book. It basically covers everything related to timekeeping.

Watch Adjustment H. Jendritzki

ISBN 10: 2883800294 ISBN 13: 9782883800298
Publisher: Antoine Simonin, 2006

http://www.booksimonin.ch/antoine-simonin-publishing.php#prettyPhoto/28/

hairspring fun.PDF

[rappeleur]

Thanks so much!! 

I already have Jendritzki’s "watch in repair" ("Die Armbanduhr in der Reparatur" in german). I have heard a lot of good things about the other you recommended. Hairspring fun  is like an oxymoron - I will have a look as well.

 

As for my timegrapher: yes, if the beat is way out, it show 9,9 ms as max value. Also 999 s/d is the max. deviation from keeping time. I read a lot of comparisons with better models in other forums, which all came to the conclusion, that the chinese timegrapher for about $ 200 is remarkably good. The waveform on the screen? Hm, I demagnetized the watch before testing, maybe it is some uneven wheel?  I had this "curve" on some other watches too (especially the very old ones), newer models show a complete straight line on the screen...