NH35 Hairspring Repair Techniques

[manjo]

Hello Watch Repairer 
After having disassembled and reassembled an ETA6497 clone movement, I am now practicing on something smaller and that is the NH35 movement. Unfortunately, when I disassembled the balanced wheel, the spring has deformed. I have now got a replacement. Unfortunately, I have not found good information on how to replace such a hairspring correctly. The videos I have found the spring is screwed. On the NH35, I think the spring is clamped. Diese Uhrwerk dient für mich nur als Übung .Does anyone know about this movement and can give me some tips or tell me how to align these pins? What should I pay attention to? This movement is just an exercise piece for me .
Thank you

 

[JohnFrum]

From the Seiko technical guide

 

[manjo]

hey thank you sooo much...this can help a lot...

Best Regards from Switzerland

 

[ColdWind]

https://docs.google.com/presentation/d/1A5rQM7MtebExRApg6elWTTBaIS_psTu1/edit?usp=share_link&ouid=102423790676520463184&rtpof=true&sd=true

This document is not mine but I i thought I should share this to you. It covered almost everything you need to know about Etachron, remove, install, adjusting, etc... and there are videos inside. Go slow and be patience and you should be able to do it. Just one more thing I want to add which is my own experience, I found that balance complete replacement parts for these Seiko movement or ETA movement aswell is not really perfect ready to go, the hairspring overcoil needed some adjustment. As you can see the distances are slightly not equal in your replacement hairspring overcoil:

If you don't make any adjustment to correct that your hairsping will look like this once installed:

Here is the final result. To me this looks idea. You can't correct this imperfection by rotating the stud carrier, bent has to be make to the hairspring. Make sure that, 1. All coils are evenly spaced, 2. The balance pivot should rest right at the center of the balance cock jewel hole, 3. The hairspring is dead flat and parralel to the balance cock and mainplate. Then you just have to adjust the Etachron regulator following the document.

 

Edited January 22, 2023 by ColdWind

[manjo]

21 hours ago, ColdWind said:

This document is not mine but I i thought I should share this to you. It covered almost everything you need to know about Etachron, remove, install, adjusting, etc...

Thank you for this guide, it's really great and now I understand the logic behind it. I would like to donate something to the author of this guide. He gave himself a lot of effort and shared his knowledge. I appreciate that very much.

 

I have now spent over 3 hours analyzing and implementing the whole thing. But I noticed that my regulator pin doesn't look like it does in the guide. The pin of my balance cock is a bit shorter and I can't squeeze it because it's too thick. If I did that, the spring would no longer burst. When I tried to press the pin, I damaged the pin a bit and had to adjust the spring again, which was also very difficult.

Can it be that the pin does not have to be pressed with this version? What will be very difficult during installation is not to damage the spring.

How does it it look? How to squeeze the pin without damaging the hairspring? Maybe someone has a good idea... 

[ColdWind]

4 hours ago, manjo said:

Thank you for this guide, it's really great and now I understand the logic behind it. I would like to donate something to the author of this guide. He gave himself a lot of effort and shared his knowledge. I appreciate that very much.

 

I have now spent over 3 hours analyzing and implementing the whole thing. But I noticed that my regulator pin doesn't look like it does in the guide. The pin of my balance cock is a bit shorter and I can't squeeze it because it's too thick. If I did that, the spring would no longer burst. When I tried to press the pin, I damaged the pin a bit and had to adjust the spring again, which was also very difficult.

Can it be that the pin does not have to be pressed with this version? What will be very difficult during installation is not to damage the spring.

How does it it look? How to squeeze the pin without damaging the hairspring? Maybe someone has a good idea... 

Oh you don't have to squeeze the regulator pin with this version. I should have mentioned it. If the hairspring could came out from the pin without the need to squeeze anything then you just guide the spring back to the pin and it's done.

[manjo]

12 minutes ago, ColdWind said:

Oh you don't have to squeeze the regulator pin with this version. I should have mentioned it. If the hairspring could came out from the pin wit

ok. I will try to install the balanced wheel back in the movement and hope it works.

 

[manjo]

On 1/23/2023 at 4:14 PM, ColdWind said:

Oh you don't have to squeeze the regulator pin with this version. I should have mentioned it. If the hairspring could came out from the pin without the need to squeeze anything then you just guide the spring back to the pin and it's done.

Since individual spare parts are not worth it, I had ordered a new movement as a replacement weeks ago. Unfortunately, I noticed yesterday that after winding the movemenr, the balance works only briefly. After 30 seconds, the balance wheel swings slower until it finally stops. Does you now what I have to pay attention to during disassembly?