ETA 1260 - performance badly degraded after servicing balance jewels.

[ChrisInOz]

Hi Folks.  This is my first attempt at servicing a non-shock balance.  The watch was in  reasonably good order before I serviced it.  Now it isn't, and I'm trying to discover what I have done wrong. 

BEFORE I did anything:  readings for dial up position were:

Rate -46 s/day,  Amplitude 257,  beat error 0.8 ms.

AFTER I cleaned and oiled the balance jewels:

Rate +660 s/day, amplitude 155,  beat error 8.5 ms.

I'm sure you can see,  this was not the outcome I was looking for.  

I only detached the hairspring stud from the cock,  and detached the balance assembly in order to get access to the upper jewels.  I didn't alter or move anything on the balance assembly.  I have not moved the hairspring collet on the staff.

I think I may have messed up when re-installing the hairspring to the balance cock. 

I have before and after pictures of the balance.  The section of the hairspring between the regulator pin and the mounting stud appears to be bulging outwards now.  Might this be the problem?  Did I do something wrong when I closed the "clamp" on the regulator pin?  I'd appreciate any advice that might get me on the right track.

Thanks and regards, Chris.

BEFORE PICTURES

      

AFTER PICTURE

 

[Nucejoe]

 Faster rate and lower amplitude,  points  to a hairspring issue, perhaps spring is rubbing on underside of the cock, and spring bulging in terminal curve section, moves impulse pin thus increased BE.

 Side view of hairspring coil, would show if its rubbing, which might happen ONLY when oscilator is swinging. 

Good luck 

 

[ChrisInOz]

2 hours ago, Nucejoe said:

Side view of hairspring coil, would show if its rubbing, which might happen ONLY when oscilator is swinging. 

Good tip! Thank you!

Side view of the hairspring shows that the regulator boot is holding the spring tightly against the pin,  at a level higher than the attachment stud.  This is pulling the spring upward into a bowl shape.  

It also looks as if this is causing the outer edge of the hairspring to touch the inboard edge of the balance cock.

See pictures.

I'm going to try, very carefully, to rotate the boot just enough to let the spring drop into its proper place.

 

 

 

 

[Neverenoughwatches]

4 hours ago, ChrisInOz said:

I'm sure you can see,  this was not the outcome I was looking for.  

   We've all been there and got the t-shirt. I also have the office shirt , tie, jacket and matching trousers, I drew the line at shiny shoes, nothing with prise me from my Converse

4 hours ago, ChrisInOz said:

only detached the hairspring stud from the cock,  and detached the balance assembly in order to get access to the upper jewels.  I didn't alter or move anything on the balance assembly.  I have not moved the hairspring collet on the staff.

I think I may have messed up when re-installing the hairspring to the balance cock. 

Easily done fella,  this is potentially a 70 yr old watch with a 70yr old hairspring, with the elasticity of Chinese takeaway soft noodle . 

Lets see if we can all chip in and help improve on it

The best picture position for the members to evaluate the hairspring is directly from above. Nevenbekriev is a wizard at pinpointing issues of the hairspring, somehow he manages to do it even with blurred pictures , like some sort of fricking guru..damn it .  So the rate has made a big jump with short oscillator swings, to me and probably everyone else that indicates some interference with the hairspring. Touching something or touching itself.... sounds pretty normal for an adolescent if you ask me ..but it's possibly 70 years old ... that  actually sounds fairly normal as well, if it's a male spring. 

A side photo also in this case would help immensely in spotting hairspring interference. 

Its the main body of the hairspring from the side that would be helpful here. 

[AndyGSi]

Is it just the angle of the photo or is it bent up / not pressed down?

[Neverenoughwatches]

4 minutes ago, AndyGSi said:

Is it just the angle of the photo or is it bent up / not pressed down?

Reg arm looks bent

Maybe it's just me but I hate to see hairsprings without a dedicated terminal curve. I fail to see how the reg arm will track the last portion of the spring, pushing the spring either in or out as the arm moves from one end to the other. The arc movement of the reg arm can't track a spiral. See the difference in the spacing of the end curve  ! 

The inner pin will pull the spring as the rate is adjusted to increase, closing up the coils at their 11 oclock position in the picture. 

[mikepilk]

11 minutes ago, Neverenoughwatches said:

Reg arm looks bent

It's not bent, it just hasn't been pushed down in to place correctly.

Gently pushing out and down at the arrow should allow it to clip back in to place.

Then the hairspring adjustment   

Edited March 24 by mikepilk

[AndyGSi]

Just realised you can see it here too.

Edit

Could it be the way they've inserted the jewel into the fork when fitting?

Edited March 24 by AndyGSi

[Neverenoughwatches]

10 minutes ago, mikepilk said:

It's not bent, it just hasn't been pushed down in to place correctly.

Gently pushing out and down at the arrow should allow it to clip back in to place.

Then the hairspring adjustment   

Good spot mike

It might click into place , unlike a shock setting though with beat adjustment.  The jewel plate holds the rate arm under it , the op might need to dissemble again.

Close up the gap on the arm and reassemble it. 

[VWatchie]

I agree with the observation made by @mikepilk and @AndyGSi. The regulator arm hasn't pressed down all the way.

Also, I noticed that the regulator arm isn't in its "before" position. It has been moved to speed up the rate towards F(ast) A(vance). Ensure the balance spring isn't pinched between the boot and the index pin before you move it back towards S(low)/R(etard).

[Neverenoughwatches]

Might be the screw above ...overtightened it and that side of the arm has popped out.

The arm doesn't click in like a shock setting, its assembled under the fixed jewel plate and held by the two screws ( heads underneath ) I do think the op needs to take apart ( as much as it's a pain ) and close up the split in the arm.

Maybe there is a bit of a leading edge on the arm or the plate ? that's forcing the arm out when the screw is tightened .

[watchweasol]

When refitting the balance and spring it’s not done on a flat surface there is always the chance of displacing the regulator arm. Done that my self as the regulator arm is split and works on a undercut and friction.

[ChrisInOz]

58 minutes ago, Neverenoughwatches said:

The arm doesn't click in like a shock setting, its assembled under the fixed jewel plate and held by the two screws ( heads underneath ) I do think the op needs to take apart ( as much as it's a pain ) and close up the split in the arm.

Yes I agree.  I will need to release the hairspring stud and take the balance off the cock again, so I can get at the jewel plate screws.  Hopefully I can then just loosen them enough to let me tuck the regulator arm in between the jewel plate and the cock, without actually taking the screws out again.

Thank you, everyone who pointed this out. I had completely missed the regulator arm split issue. Clearly I need to improve my observation skills.

1 hour ago, VWatchie said:

Ensure the balance spring isn't pinched between the boot and the index pin before you move it back towards S(low)/R(etard).

I think the boot is definitely pinching the spring against the index pin at the moment,  and that is part of the reason why the spring is being pulled up into a bowl shape.  I will correct that when I reassemble after re-seating the regulator arm.

18 minutes ago, watchweasol said:

When refitting the balance and spring it’s not done on a flat surface there is always the chance of displacing the regulator arm. Done that my self as the regulator arm is split and works on a undercut and friction.

The regulator arm was detached when I took out the jewel plate for cleaning,  as it is the jewel plate that holds it on the balance cock.  I was always going to have to reset it because of that.  I just haven't done it yet, because my faults in assembly had completely messed up the performance of the balance.

1 hour ago, Neverenoughwatches said:

See the difference in the spacing of the end curve  !

This may be partly due to the regulator boot pinching the spring against the index pin.  I think the end curve may be under compression between the regulator and the stud.

[Neverenoughwatches]

14 minutes ago, ChrisInOz said:

Yes I agree.  I will need to release the hairspring stud and take the balance off the cock again, so I can get at the jewel plate screws.  Hopefully I can then just loosen them enough to let me tuck the regulator arm in between the jewel plate and the cock, without actually taking the screws out again.

If you're going that far, it might be as well to take off the arm completely and close it up a touch. There's a reason it has jumped out ( maybe when you adjusted the rate )  as ww said there is a bevel to the plate, if i remember correctly usually one to the arm as well that helps to centralise the two parts when they're screwed together. I might suggest a very thin smear of grease to one of the bevels, you don't want to see the grease or it will be too much. Maybe a toothpick lightly pushed into candlewax and then run it around the rim....might be an interesting idea.

26 minutes ago, ChrisInOz said:

2 hours ago, Neverenoughwatches said:

See the difference in the spacing of the end curve  !

This may be partly due to the regulator boot pinching the spring against the index pin.  I think the end curve may be under compression between the regulator and the stud.

You need to see what the hairspring is doing without any interference from the regulator pin. Widen the pin/ boot spacing and set the arm along the final coil so neither is touching. Now you can see how the hairspring is behaving between its two fixed points ( ends )

[Nucejoe]

 Notice the width of slot is about 2 to 3 times the thickness of hairspring. 

[nickelsilver]

The hairspring isn't centered as it was originally. Press at the arrow to get the coil spacing even. The regulator pin gap should be 1.5-2x the hairspring thickness, and the spring should be centered in the gap when at rest. You will have to make gentle nudges at the stud to center it once you've centered the body (coils) by pressing at the arrow. The regulator curve should follow an arc centered on the balance center.

 

It's also out of flat; manipulate it at the stud to bring the opposite side down, and you may still need to lower the stud.

 

The current condition could have the hairspring touching the stud and/or the underside of the balance cock.

 

 

[ChrisInOz]

1 hour ago, nickelsilver said:

The regulator pin gap should be 1.5-2x the hairspring thickness, and the spring should be centered in the gap when at rest.

Pardon me if this is a dumb question, but is this the gap that should be maintained during normal operation of the watch? 

2 hours ago, Neverenoughwatches said:

I might suggest a very thin smear of grease to one of the bevels, you don't want to see the grease or it will be too much.

 

I have some Moebius 9504. Is that suitable?

 

[nickelsilver]

9 minutes ago, ChrisInOz said:

Pardon me if this is a dumb question, but is this the gap that should be maintained during normal operation of the watch?

Yes, on a flat hairspring, which you have, you want the gap about that size. On a Breguet (overcoil) you want it as small as possible without binding.

[Neverenoughwatches]

42 minutes ago, ChrisInOz said:

Pardon me if this is a dumb question, but is this the gap that should be maintained during normal operation of the watch? 

 

I have some Moebius 9504. Is that suitable?

 

It's maybe not something that anyone else does,  but I had a really stiff reg arm a while back, so i greased the ring very lightly where it fits the jewel plate to ease it up a bit. The candle grease was more of an idea for experimentation,  i know someone that uses candle grease on a mainspring ! Wierd.... right ?

[nevenbekriev]

Did You correct this? Not needed to remove the enstone plate, just pressing down the regulator exactly where the arrow is enough, but first remove the balance and press while the cock is supported on something.

The hairspring is not centered and what @nickelsilver  said is the way to correct it, but the reason possibly is that the stud is placed turned in the hole and the screw tightened while the stud is not in correct orientation. Turning the stud clockwise if seen from above will help to center the spring

It will be good if we can see a picture of the hairspring while balance over the cock

[ChrisInOz]

2 hours ago, nevenbekriev said:

Did You correct this? Not needed to remove the enstone plate, just pressing down the regulator exactly where the arrow is enough, but first remove the balance and press while the cock is supported on something.

I haven't done this yet.   I will post more pictures when I do.

[ChrisInOz]

OK, I have fixed the regulator arm issue.  It just snapped into place without any need to loosen the jewel plate screws.  It seems to have a positive grip on the plate. It is not difficult to move,  so I have decided not to grease it.

The hairspring looks reasonably flat when sitting on the balance with the stud end free.

 

 

The top pivot looks a bit weird,  but it seems to be working OK.  I have not done any work on it.

I will do more pictures after I have reattached the balance to the cock.

[caseback]

1 hour ago, ChrisInOz said:

The top pivot looks a bit weird,  but it seems to be working OK.  I have not done any work on it.

Looks bent, but that might be an optical illusion. It's funny how that works sometimes. Do you have truing calipers to check?

[ChrisInOz]

AAAAAIEEEEEEEEE!!!!!!!!!

I've BROKEN THE BALANCE !!!!!

I fixed the problems with the regulator arm,  set the boot correctly,  got the hairspring back into reasonable shape.  The movement looked to be running better,  so I took it over to test it on the timegrapher,  only to accidentally catch the balance wheel against the jaws and break off the top pivot.

What a clumsy fool. I am totally disgusted with myself.

 

[VWatchie]

14 minutes ago, ChrisInOz said:

What a clumsy fool. I am totally disgusted with myself.

Don't worry, Chris! We've all been there, and it's a part of the learning process. You never stop making mistakes, but gradually, you develop strategies to minimize the risks.

The way out here will be to replace the balance staff. However, that's something that requires quite a few tools, such as a staking set and suitable punches. Perhaps the easiest way out will be to try to source a balance complete (balance wheel + balance staff + balance spring) from a donor movement if one can be found.

Edited March 26 by VWatchie