Bulova 11AF Will Not Run

[Berwolf]

Bought a 1950/60 Bulova watch that has an 11AF movement. When I got it the watch would run intermittently, so decided to take it apart, clean and reassemble to see if that would fix the intermittent issue.

 

Watch is now reassembled but will not run. Here is a list of checks.

 

1. Have disassembled and reassembled three times now looking for something that was maybe off, but has not changed. 

2. I replaced the mainspring with a NOS one, the one I received was 10mm in diameter and would not fit as the barrel is 9.1mm. I rewound the NOS spring and installed it because the original bridle was broken. I also noticed the shape of the NOS spring was different from the original. When assembled the watch winds fully and nothing obvious I can tell with the barrel and mainspring, not sure if the wrong mainspring would cause the watch not to run?

3. The barrel has some play in the bridge, it does seem borderline acceptable, would this cause the watch not to run or just run poorly?

4. When the bridge and train of wheels are installed everything seems to run smoothly, I have looked at end shake and all wheels have a little play, nothing seems excessive but this is only my second watch repair so take that for what it is worth.

5. Have inspected the jewels and pivots on all the wheels, pallet fork and hairspring, all are present and appear to be ok.

6. When I install the pallet fork and wind the watch the pallet fork "jumps" and holds when I move it with tweezers.

7. When I install the mainspring it won't run on its own. If I blow it with air it will run for a second or two and then stop.

Would appreciate any help on troubleshooting and possible issues to look for. 

Thanks in advance. 

[HectorLooi]

Power down the mainspring, remove the pallet bridge and fork snd reinstall the balance. Use a blower to puff air on the balance and see if it swings freely.

Did you remove the balance jewels, clean and oil them correctly?

[GuyMontag]

After installing the balance does the balance move freely when you blow a puff of air on it (is the impulse jewel located between the pallet stones)?

[Nucejoe]

2 hours ago, Berwolf said:

 and holds when I move it with tweezers.

Will you elaborate on this.

  

 Sounds as if impluse jewel is way out of beat or missing .

[nevenbekriev]

Sounds to me like the balance does not oscillate free. Remove the lever and do the free oscillations test as adviced above. Look at the hairspring condition and position. Pictures are welcome

[Berwolf]

4 hours ago, HectorLooi said:

Power down the mainspring, remove the pallet bridge and fork snd reinstall the balance. Use a blower to puff air on the balance and see if it swings freely.

Did you remove the balance jewels, clean and oil them correctly?

Removed the pallet bridge and fork and used a puffer on the balance, it oscillated for 2-3 seconds before coming to a stop.  I removed the jewels for the balance cleaned them in one dip and then applied a small dot of oil.  I have attached a picture of the balance if someone notices something. 

[HectorLooi]

The balance should oscillate for at least a minute. There is too much friction somewhere. Did you inspect the the jewels for damage? Did you use the correct oil? Is the hairspring lying flat and not fouling on anything?

[JackH]

I would check that the balance capstones are facing the right way. Flat side to pivot.

Edited December 10, 2023 by JackH

[Berwolf]

1 hour ago, JackH said:

I would check that the balance capstones are facing the right way. Flat side to pivot.

I removed the cap jewels from the balance and blew on it with air, no change and not sure if there would be. Just thought if there was to much friction between the pivot and jewel this would eliminate it. Also, the best I can tell the cap jewels are flat on both sides. Is there a way to adjust the jewels on a setting like these?

[HectorLooi]

Endstones are always flat on one side and convex on the other. Use a torch to shine at an angle to see the reflection to check for the flat side.

Sometimes the upper jewel and lower jewel are different. If you accidentally mixed them up, try swapping them around.

Also, see if loosening the balance cock screw frees up the balance.

[Berwolf]

Thanks I will spend some more time going over the balance and the jewels.  I noticed when troubleshooting that the balance slows down once I fully tighten the screw for the bridge.

[JohnR725]

7 hours ago, HectorLooi said:

Is the hairspring lying flat and not fouling on anything?

Often overlooked is the hairspring. If the hairspring isn't flat and isn't exactly where it's supposed to be in other words it just touches the balance arms of the balance bridge it's amazing how much amplitude you're going to lose if it's not where it's supposed to be.

[nevenbekriev]

12 hours ago, Berwolf said:

...4. When the bridge and train of wheels are installed everything seems to run smoothly, I have looked at end shake and all wheels have a little play...

What about the balance? It should have about the same axial free play as the lever and escape wheel.

And yes, the hairspring is the thing that one have to learn when it is not positioned right and touches balance spokes or cock and needs to be rectified.

[Berwolf]

First thanks for everyone's feedback and trouble shooting help.  I was able to spend some time going over a few of the recommendations. 

I was able to determine the convex and flat sides of the endstones and am now confident they are correct. After confirming this the free oscillation time increased from 2-3 seconds to probably around 10 seconds and I no longer notice a change between a loose balance bridge and fully tightened. 

The next steps will be removing the balance spring to determine if it is flat and/or bent. One thing I was trying to confirm before doing this is what if any orientation notes or markings maybe needed so it can go back together more easily? Once it is disassembled i plan to check if it lays flat or has a dish, the spacing is all even between the coils and when installed on the bridge without the wheel the collet is centered over the endstone across the full range of the regulator arm.  Anything else to check?

One other check I plan on running is to see if the balance wheel without the hairspring runs ok. Looking at it relative to the bridge it does appear not completely parallel but not sure if this would be due to the hairspring or the pivots and bridge. 

[Nucejoe]

1 hour ago, Berwolf said:

 The next steps will be removing the balance spring to determine if it is flat and/or bent. 

 No need to remove the spring to determime if its flat or unlevel.

Just hold the balance vertical , balance staff horizental.

Spring removal is justifiable only if the coil needs sorting out or other work. Some folks can do basic sorting out with spring attached to the balance.

1 hour ago, Berwolf said:

One other check I plan on running is to see if the balance wheel without the hairspring runs ok. 

If the balance wheel turns, how would you determine if is turning free enough? 

Rgds

[ManSkirtBrew]

Even though you checked, first thing I would check again is your balance staff pivots. I know when I was first starting, even a broken pivot looked okay to me, and it'll still assemble fine and often run (albeit poorly) with a bad pivot. Take a close look under as high magnification as you can get. The one on the right is broken, left is not:

Or bent like this guy:

 

You want to see this:

[JohnR725]

4 hours ago, Berwolf said:

The next steps will be removing the balance spring to determine if it is flat and/or bent.

This is definitely something you do not want to do. Often times will get pictures the balance wheel and hairspring out of the watch in the problem is that's not where the problem is the problem is in the watch. You need to look in at the hairspring in the watch to see if it's flat removing it will reveal nothing in fact usually hairsprings will look perfect out of the watch. For instance if you bent at the stud which is a very commonplace to get bent out of the watch the stud is at an angle which it probably never see and they hairspring will look flat so leave the balance wheel and hairspring in the watch and look and study is there that's where the problem is not out of the watch

[Nucejoe]

Hold the balance complete with tweezers like this, balance vertical ,

https://thumbs.worthpoint.com/zoom/images4/1/1015/04/genuine-rolex-1570-1575-1556-1556_1_0b114f4569141bc0ec28ba25534c28a1.jpg

1-if the coil and balance are parrallel , the coil is level. 

2-if the coil is all in one plane its flat.

No need removing the spring.

 

[Kalanag]

5 minutes ago, Nucejoe said:

https://thumbs.worthpoint.com/zoom/images4/1/1015/04/genuine-rolex-1570-1575-1556-1556_1_0b114f4569141bc0ec28ba25534c28a1.jpg

Link doesn‘t work…

[Nucejoe]

Just now, Kalanag said:

Link doesn‘t work…

Strange, works here without VPN. 

Have you checked your settings, perhaps need an app to open it.

[Kalanag]

1 minute ago, Nucejoe said:

Strange, works here without VPN. 

Have you checked your settings, perhaps need an app to open it.

It says:

„Direct image access denied, please go to worthpoint.com to view images.“

[RichardHarris123]

Works for me, no VPN. On my android phone. 

[Nucejoe]

2 minutes ago, Kalanag said:

It says:

„Direct image access denied, please go to worthpoint.com to view images.“

 I don't quit undrrstand when it says " the link couldn't be embeded cuz URL is not allowed " , could this be why kalanag is refered to the original site? 

[Kalanag]

 Problem solved! The link works when I first open the WorthPoint website on a parallel browser window!

Edited December 13, 2023 by Kalanag

[Nucejoe]

 When balance is held horizental with the stud at six Oclock, a flat coil is parrallel to the balance plus both sides of the coil easily viewed.