Watch keeps stopping (hairspring issue?)

[SudoHalt]

Hey there,

I have had a watch with the Chinese Standard Movement suddenly die on me over a year ago. The issue is, the watch abruptly dies in certain orientations, even with a full power reserve.

I decided to open it up today and try to figure out what's going on. Since I don't really care about that watch, the outcome doesn't matter to me, it would be interesting to "diagnose" the problem as a starter. Prior to today, the watch was never disassembled once and the watch has has never been through any unusual beating.

While my methods of disassembly and handling might be a problem on their own, the watch had a problem to start with. I have tried removing the balance bridge and putting it back into place, but to no avail. Interestingly, halfway through a very gentle unscrewing of the balance bridge screw, the head broke off from the threaded part. I have dealt with smaller screws in the past, but never this problem.

In one of my attempts to put the balance bridge back into place, I got it to seemingly work, but the amplitude was visibly terrible.
In another attempt, I tried my best to center the balance wheel, but if I screw the balance bridge completely, it stops. The end shake seems to be reasonable, though.

The rest of the watch seems to be in a pretty workable condition.

This makes me feel it's an issue with the hairspring. The tiny pivots of the balance wheel appear pretty well intact. One thing, I did notice though, is that the spring is somewhat distorted such that the balance wheel is off center.

Attached is a video to show the issue. This is just after I removed the caseback. All components untouched otherwise. The pictures are taken after the handling and everything.

May I know what do you think of it?

[nickelsilver]

The hairspring is destroyed. That it even ticks is surprising!

[oldhippy]

You need to detach the balance from the bridge to see exactly how bad the hairspring is, when it is still attached looks can be deceiving. The other thing I have spotted is someone has put two nicks on the bottom plate where the balance bridge sits and screwed down, this will affect the end shake to the balance and also the angle of the balance bridge.    

[SudoHalt]

Got it! I am pretty sure my handling was a major contributor to this. But as I said earlier, the watch had an issue (likely with the hairspring) even before any handling. Could the hairspring really go bust even when the movement is cased? Something doesn't add up to me.

[oldhippy]

I would say at some time that watch has been dropped onto something hard or its taken one hell of a knock. 

[SudoHalt]

Am I understanding that it is possible to deform the hairspring like this without breaking the pivots of the balance wheel?

[nickelsilver]

2 minutes ago, SudoHalt said:

Am I understanding that it is possible to deform the hairspring like this without breaking the pivots of the balance wheel?

Absolutely, the hairspring is the most delicate thing in the watch- when it comes to manipulation.

 

It's unlikely that the hairspring was like that before you removed the balance cock. It simply wouldn't have run. It can't get like that from a drop or even being thrown from a rooftop.

 

As I understand it, the Chinese movements often leave the factory unlubricated and even with manufacturing debris present. This was probably the cause of stopping.

Edited February 18, 2020 by nickelsilver

[Nucejoe]

Pivot must be out of jewel hole in the first picture. Let us see a top view of the coil with pivot in jewel hole.

Looks repairable specially if the collet is removable. 

Next you may need to detatch the balance complete from the cock. Lets see the coil then.

As for the broken screw, check if any of it sticks out the other end, else you will need some alum.

 

 

[Nucejoe]

Gouge is the birth mark of Chineese movements.  Fully strip down the movement to get the main plate isolated before you alum.

[SudoHalt]

1 hour ago, nickelsilver said:

Absolutely, the hairspring is the most delicate thing in the watch- when it comes to manipulation.

 

It's unlikely that the hairspring was like that before you removed the balance cock. It simply wouldn't have run. It can't get like that from a drop or even being thrown from a rooftop.

 

As I understand it, the Chinese movements often leave the factory unlubricated and even with manufacturing debris present. This was probably the cause of stopping.

You actually are right, I just found a picture before I touched anything and the hairspring looked decent. It was not an ingenious idea to practice using tweezers on the balance bridge, but I am glad I could handle it better by the end. Nonetheless, it was intended as a practice watch anyway. That hairspring looks to be beyond repair now.

Having now seen the original state of the hairspring, I am actually confused. The watch was running flawlessly for over a year but then one day it died on me. What could have caused this? The thing is it appears to me that the pallet fork moves pretty freely.

@Nucejoe I guess the second picture is what you'd be looking for. I kinda feel ashamed to be here.

 

 

 

Edited February 18, 2020 by SudoHalt

[Nucejoe]

I put some penetrating oil on the stud screw and top of the stud as well as the boot, let soak over night, if needed soak longer to remove balance complete. Oil around the jewel housing too.

Dismantle the cock, remove the regulator arm and stud career. Remove the jewel housing, shock spring go in lighter fluid.

Show a picture of the coil while on balance wheel. 

Except balance complete, balance jewels, the rest takes a 24 hr bath in Cocacola ( I mean the entire movement).

  Other screws that have enjoyed the coke bath will unscrew real easy. brush all with tooth brush use powder laundrey detergent. 

Gears and pinions take a half hr bath in vinager and get rinsed and brushed under tap water, use powder detergent. Important to time the vinegar bath, no longer than thirty mins.  

 

 

[Elton]

Since you,'ve removed the balance wheel, I would try removing the pallet fork and see if the gear train runs smoothly eliminating the possibility of sticky gear train. 

[SudoHalt]

After going through the wheels in the barrel bridge, I figured out what was the culprit in making the watch stop in some different orientations when the hairspring was still in pristine condition. The wheel which moves the minute hand (maybe) turned out to have a broken pivot. When in the right orientation, it doesn't jam and engages with the center wheel.

In the right orientation, it still has enough torque to drive the faster center wheel, but not as much as an intact wheel. I therefore believe the broken pivot is what made made it go at a much lower amplitude. Interestingly, the barrel wheel kept that broken wheel loosely pushed against the top jewel, which is why the wheel was never completely knocked outside its place and could still be put back in place by placing the watch in another orientation.

I might have done very stupid things to the mainspring, but I am happy that I am learning quite a bit on other things too. It's pleasantly intriguing.

Do you think there is anything I got wrong? I have attached the pictures of the broken pivot in jewel on the mainplate, and that of the wheel. Sorry if the mainplate is too painful to look at. xD

That pivot was absolutely minuscule! I really think I need to get some amateur loupe.