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Posted

I was putting back together a 70s Seiko chronograph and noticed that the hairspring had bad amplitude. It was like this when I got it.

I disassembled the balance ensemble and saw that the hairspring is leaning on one side quite a lot. I checked to see if it was the stud's own weight but it doesn't seem to be it.

Any pointers? Did it bend somewhere along the coils ? The movement is in good shape with no damaged parts. 

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Posted

Is it touching anything when assembled? 

If you are sure its not the stud, here is where you need to go, with any type of alteration of a hairspring be very careful it doesn't take much to turn it into a complete nightmare.  

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Posted

It seems to be fine when assembled. (I don't know what the reason for low amplitude is atm, it could be something else)

I'm just unsure as I've never seen a hairspring leaning like this. 

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Posted

Is the hairspring moving between the regulator? I t must be able to rebound and no matter where the regulator is positioned. It looks a little low between that regulator.  

Posted

As a general test for leaning coil , hold the balance assembly vertical.

Where OH shows, seem to have been pushed down, do not attempt raising by getting your screwdriver under it, try by manipulating the inner coil where the bend starts.

Posted

There could be a number of things. I suggest you look at all parts of the escapement. Make sure all the jewels are clean and are in there fittings correctly, if you removed end stones have you put them back in the same way as you removed them. Is the impulse jewel clean and not loose same goes for pallet jewels. Have you used the correct oil for the escapement. Is the hairspring tight on the staff. What is the end shake like. 

Posted

All parts have been cleaned and properly lubricated. Nothing is damaged. All were fit back correctly.

I'm starting to wonder if the mainspring might be the culprit here.

I've only assembled the movement with the bare minimum (withoutchrono, calendar, etc.) and the amplitude is still low.

I don't have a mainspring winder so I didn't remove it o see what it's like. I did clean up the barrel. Tried both with and without lubricant inside, same outcome.

Posted

Back in the 70's & 80's when I was sitting at the bench Seiko advised us to replace the complete barrel with a new unit. I know that can't be done now because many parts are unavailable, so a new M/S might be the answer. 

Posted

I don't have a timegrapher but it's very low. Any lower and the balance would no longer rotate. 

Is it possible that something else could cause this? The mainspring seems ok to my untrained eye as I look at it sitting inside the barrel.

Keep in mind that this is the amplitude that I get if the center seconds chrono hand is enabled. If I have all the chrono parts installed and I don't turn on the chrono function the amplitude is even lower.

Posted

I agree with OH about the problem being at the inner coil, likely is touching so the watch won't really run. I met a same one recently, I think I had lifted with spring.

Mark correcting a same hairspring below

A timegrapher is absolutely needed for this type of work, and as noted above this is delicate work, there is no more good availability of these balances, so unless one is absolutely able and sure it would be better to give it to a professional. 

Posted

Well, I think that I've leveled the hairspring but that didn't change anything. Amplitude is still very low.

If I rotate the mainspring barrel with my tweezers the amplitude will still be low. This should rule out the mainspring, right ?

Posted
54 minutes ago, Chopin said:

Well, I think that I've leveled the hairspring but that didn't change anything. Amplitude is still very low.

 

On 10/18/2020 at 2:36 AM, Chopin said:

hairspring had bad amplitude

I find this is an interesting discussion that amplitude is controlled by the hairspring? What about all those other thing is that affect amplitude should I just forget about those in the future?

A really interesting diagnostic tool is a timing machine it be really interesting to see this watch Timed in dial-up, dial down and at least one crown position preferably more than one. Amazing how many things we can see. In fact for the timing machine you can see things that you cannot see any other way.

Then yes they hairspring can affect amplitude but it's not the only thing. I notice this appears to be a Seiko chronograph? The problem with chronograph watches are there's all sorts of additional gears that could be robbing you of power. What was the condition of the watch in before you serviced?'s did you notice anything that looked undesirable in the servicing?

 

Posted

The watch seemed to have low amplitude from the beginning I got it. It had no major functioning issues.

I wonder if the fact that one of the pallet jewels isn't fully inserted might have anything to do with this. (left one)

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Posted

I think you'll find with all Seiko watches the amplitude is low. Then I think you will find that most watch companies could care less about the amplitude for the most part except 24 hours later. They're much more concerned about timekeeping.

I still think one of those modern nifty devices called a timing machine would be helpful here.

Then that's a nice pallet fork picture but it be helpful if it was in the watch. There are escapement checks to make sure things are right that's the only way we can tell if the stones or where there supposed to be.

 

Posted

 Do you see any sign ( under high magnifiction and good light) indicating pallets may have moved?  Not fully inserted doesn't indicate wrong adjust/position of the pallet. Also check pallet face for wear, scratch or chipped off etc.

Pallets might need adjustment, but no way to tell by position of the pallet.

A hesitation appears in oscilation, looks to slow down and pick up speed again, if so, that has to do with faulty, dirty or wobbling escape wheel.

Posted

Looks like another case where without a timegrapher picture or even a sound recording, one is left guessing.

Posted
On 10/18/2020 at 1:25 PM, Chopin said:

 

I don't have a timegrapher but it's very low. Any lower and the balance would no longer rotate. 

 

I want to say I did not think of this. I read about it on this forum.

If you have a smart phone with slow motion video, you can video the balance for 10 seconds or so and then replay it at slow speed. This will allow you to see a more accurate view of amplitude.

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