Issue with Bulova 23

[Wdschell]

Hello all,

was working on servicing this Bulova 23 I got at a pawn shop.  It was running before, but stopping.  I stripped it all down and cleaned it.  I was putting it back together and oiling it today and I finally got the balance back it and this is what it is doing.  I have checked the banking manually and it looks ok so I am guessing the balance is the issue?  Any help is appreciated.

https://photos.app.goo.gl/CS44qkVSn1YwgFmt8

it is like the balance banks everything correctly and then stops

[Nucejoe]

Untimely/ faulty  impulse delivery or damaged staff/ jewel assembly.

-Check entire escapement under good magnification.

- Adjust for in-beat impulse.

Good luck

 

[watchweasol]

Hi   In addition to Joes comments  check end shake  on the balance,  and the alignment of the balance spring that its not catching or rubbing on th balance cock.

[WellAdjusted]

It looks like something is rubbing or scraping. The above suggestions seem likely.

For these watches, it is common for the hairspring to rub against the arms of the balance wheel or against the underside of the balance cock.

You might confirm that the wheel isn't rubbing against the pallet bridge or the center wheel.

[Wdschell]

The balance staff and the impulse jewel looked ok to me under magnification.

What is the solution if the hairspring is rubbing? it need to be adjusted I would assume?

[Nucejoe]

Observe the coil from side view of the balance while running, a close up video of balance looking streight down on the bridge and side view showing the coil helps.

Coil should be flat, level with concentric circles and not foul itself.

Judging from the previous video, amplitude seems good which is a sign of hairspring free from rubbing, however you give the balance plenty of swing when you nudge it,  instead gently move the wheel see if it picks up and go at some point. (I think the balance is out of beat)

I always put just  the balance complete and bridge back( no other part)  on the mainplate for final adjustment leveling etc.  it will give you almost 330 access to the HS  around the balance wheel 

What happens if you turn a gear, third or center ? 

 

 

 

 

[clockboy]

Agree with the above comments but also check the escape wheel teeth, just one tooth being a touch out of shape will cause the stops.

[WellAdjusted]

I'll second that it's a good practice to replace just the balance complete prior to assembly so you can get a good look at the hairspring.

After doing that, you can add the pallet fork and bridge to see how the fork and jewel interact.

[Wdschell]

Thanks so much for all the suggestions, troubleshooting alone is super frustrating.  I did inspect the teeth on the escape wheel under magnification for a full rotation and didn't see anything out of the ordinary

 

Here are some more videos of it running.  Excuse the potato quality.  I was filming from my ipad through a magnifier.  Though it seems to have decided to start running since last night.  The only thing I did different since this was to give the balance complete a lighter fluid bath

Bulova 23 issue https://imgur.com/gallery/PN5Ocr7

 

Edited March 2, 2021 by Wdschell

[Wdschell]

Also here is what it looks like on the timegrapher after it decided to run.  The beat error was something like 9.9ms before I adjusted it.

 

 

Edited March 2, 2021 by Wdschell

[Wdschell]

Solved I think...

I decided to give everything another look and low and behold the pallet fork stones basically fell out while I was inspecting it.

I decided to check them with just a little pressure and the moved.  Best to get a new fork or can these be glued back in?

[Nucejoe]

53 minutes ago, Wdschell said:

 Best to get a new fork or can these be glued back in?

Pallets are usually shelaced since it wont harm the base metal forks are forged out of, Marks shows how to make this tool to warm the fork on and shelac the pallet jewels, I use epoxy five on cheap pieces.

 Pallets adjustment is no easy task, nevertheless if you like to give it a try, there be plenty help and advice besides Marks lessons.

I couldn't find a link to relevent threads , some one may have more luck than I and find em.

 

 

[WellAdjusted]

Loose pallet jewels would do it. This is an uncommon fault, so it's worth reflecting on the cleaning procedures to see if something could have dissolved or softened the shellac. You might also check the roller jewel, which is also secured with shellac.

Replacing the jewels is not too hard, but replacing them to the proper depth is another matter. It's interesting and worth trying, but you might source a replacement pallet fork for now while you read up on it.

[LittleWatchShop]

What a great thread.  You guys are amazing--glad I found this forum!

[Wdschell]

10 minutes ago, WellAdjusted said:

Loose pallet jewels would do it. This is an uncommon fault, so it's worth reflecting on the cleaning procedures to see if something could have dissolved or softened the shellac. You might also check the roller jewel, which is also secured with shellac.

Replacing the jewels is not too hard, but replacing them to the proper depth is another matter. It's interesting and worth trying, but you might source a replacement pallet fork for now while you read up on it.

Dang I didn't think about the roller jewel dissolving too.  I used some generic jewelry cleaner on the fork.  I just lighter fluid on the balance complete.  I'll check it.  I am currently sourcing a 10bzac movement for the fork.  I think Dave's watch parts has one.  Waiting to hear back

[Wdschell]

Whew, the impulse jewel is safe...

[JohnR725]

12 hours ago, Wdschell said:

pallet fork stones basically fell out while I was inspecting it.

It's extremely unusual that the pallet stones fallout I would definitely change your cleaning fluid. Sometimes they can be loose but usually there's visually still shellac on them

Then if you decide to put the stones back in they have to go in a specific location. The angle on each stone is slightly different so you have to put the right stone in the right slot. Then a course comes the fun of adjustment which is why we use shellac because it allows you to warm it up shellac softens the stones can be moved in and out as necessary.

Then you want to be careful when you using generic jewelry cleaners or other cleaning fluids because interesting things can happen that normally wouldn't happen if you're using proper fluids. Jewelry cleaners are not usually expecting all sorts of different metals and that can result in interesting undesirable consequences also.

7 hours ago, Wdschell said:

the impulse jewel is safe

.Roller jewel's especially on American pocket watches do tend to suffer more than the pallet stones. So in the case of a pocket watches it's always worthy to check the roller jewel to make sure it still  locked in place.

 

[Wdschell]

Just wanted to update this thread again. 

It was indeed my fault for using the wrong cleaner to clean the pallet fork.

I got the new parts movement yesterday, installed the pallet fork and was having the same issue.  The escape wheel looked fine but since I had another I went ahead and swapped it in and voila, it is ticking away and I cant hear or see anything wrong with it now.  I inspected the old gear, but I just cant see anything wrong with it.  Even compared it to the one I swapped in. 

Looks great on the time grapher now.  Thanks for all of your help in this.  Mostly, I need to bounce ideas off of someone when troubleshooting and you guys were awesome for that.  I am sure I will be around again as I think my Seiko 6139 has a loose canon pinion

[watchweasol]

tHi  Brilliant , its all working now great attached a couple of sheets on the 6139 for the future Job.    all the best.

6510_Seiko 6139A (1).pdf 483_Seiko6139B (3).pdf