1956 Bulova 10BPAC 23 jewels service

[ManSkirtBrew]

While I'm waiting for cleaning chemicals to arrive, took apart this nice Bulova 10BPAC. I love the fluted bezel, and I really enjoy these Bulova movements.

This is a watch I picked up from Facebook Marketplace when I first started, and was too intimidated by the automatic works to take it apart.

It's time is now! I also pre-emptively bought a parts watch from eBay (on the right in the photo). It's got a yellowed dial, but otherwise looks nice as well. I'll open that one up next, but I've run out of parts trays

I even bought the Bergeon #3 Presto tool to pull that sweep seconds wheel.

It's a non-runner. The balance looks good, no cracked jewels, but there's a lot of resistance in the train. The stem had some serious corrosion, and it got all around the watch, so I'm hoping a good cleaning and oiling is all it needs.

Now the only question is: do I follow directions, or do I take this spring out and clean & lubricate it? I've never been good at taking orders...

[Nucejoe]

 I don't suppose you looked at variations in 4 positions before disassembly. I know I need all the lessons on such adjustment.   

This guy answers your questions or used to. 

https://adjustingvintagewatches.com/adjusting-to-5-positions-wristwatch/

 Lovely movement, enjoy wearing it in good health.

 

 

 

[ManSkirtBrew]

6 hours ago, Nucejoe said:

I don't suppose you looked at variations in 4 positions before disassembly

I tried testing it for a baseline first, but it wouldn't run. The balance appears to spin freely, but there's not much power coming through the train.

Edited January 5, 2023 by ManSkirtBrew

[Levine98]

13 hours ago, ManSkirtBrew said:

While I'm waiting for cleaning chemicals to arrive, took apart this nice Bulova 10BPAC. I love the fluted bezel, and I really enjoy these Bulova movements.

This is a watch I picked up from Facebook Marketplace when I first started, and was too intimidated by the automatic works to take it apart.

It's time is now! I also pre-emptively bought a parts watch from eBay (on the right in the photo). It's got a yellowed dial, but otherwise looks nice as well. I'll open that one up next, but I've run out of parts trays

I even bought the Bergeon #3 Presto tool to pull that sweep seconds wheel.

It's a non-runner. The balance looks good, no cracked jewels, but there's a lot of resistance in the train. The stem had some serious corrosion, and it got all around the watch, so I'm hoping a good cleaning and oiling is all it needs.

Now the only question is: do I follow directions, or do I take this spring out and clean & lubricate it? I've never been good at taking orders...

Yes, take the mainspring out, clean and lube. I've worked on about a dozen of these in the last 4 months--let me know if you need qny help. One thing to definitely look out for is play between the barrel arbor and the bridge--not correcting that will casue a significant loss of amplitude. Also, do you have any plans for the donor case? I'm in need of one for a movement I have. If so, PM me. Thanks

[Nucejoe]

14 hours ago, ManSkirtBrew said:

While I'm waiting for cleaning chemicals to arrive, took apart this nice Bulova 10BPAC. I love the fluted bezel, and I really enjoy these Bulova movements.

This is a watch I picked up from Facebook Marketplace when I first started, and was too intimidated by the automatic works to take it apart.

It's time is now! I also pre-emptively bought a parts watch from eBay (on the right in the photo). It's got a yellowed dial, but otherwise looks nice as well. I'll open that .

Now the only question is: do I follow directions, or do I take this spring out and clean & lubricate it? I've never been good at taking orders...

 

Even if you are not impressed with its positional variations.  this quality movement deserves new mainsprings. 

 

[ManSkirtBrew]

2 hours ago, Levine98 said:

One thing to definitely look out for is play between the barrel arbor and the bridge

I did notice a bit more than I'd like. It looks like there's already a brass insert there, but I couldn't tell if it was factory or not. I'll get some photos later.

 

2 hours ago, Levine98 said:

Also, do you have any plans for the donor case? I'm in need of one for a movement I have.

I was going to see what the donor movement looked like and possibly put it back on eBay, but I'd much rather see it go to a fellow WRTer. Once I get a little further into the project I'll let you know.

1 hour ago, Nucejoe said:

this quality movement deserves new mainsprings. 

I tend to agree, although I don't see a listing in the GR mainspring catalog for this one. I'll take it out and get some measurements.

[GuyMontag]

I love these Bulova 23's, I have a few of these myself. If you don't already have it, here is a good tech sheet for these movements.

Bulova_10BOAC_10BPAC_10CBAC_TECH_1954.pdf

[Levine98]

51 minutes ago, ManSkirtBrew said:

I did notice a bit more than I'd like. It looks like there's already a brass insert there, but I couldn't tell if it was factory or not. I'll get some photos later.

 

I was going to see what the donor movement looked like and possibly put it back on eBay, but I'd much rather see it go to a fellow WRTer. Once I get a little further into the project I'll let you know.

I tend to agree, although I don't see a listing in the GR mainspring catalog for this one. I'll take it out and get some measurements.

You can get  a replacement from Cousins UK using the measurements (120/10/300 I think—I just ordered 2). One thing I’ve found is Cousins has faster shipping and cheaper prices on most everything compared to Otto Frei or Cas-Ker (or any US material house). 

BTW I found a great article on the history of Bulova 23s if you’re interested (got it off the NAWCC forum). Let me know and I’ll pass it alone). Jay (Richmond VA (804) 998-3519)

58 minutes ago, ManSkirtBrew said:

tend to agree, although I don't see a listing in the GR mainspring catalog for this one. I'll take it out and get some measurements.

Just my .02 but you don’t have to replace the mainspring by default—if it looks good (good shape, no grinks), just clean it and relube and reinstall—I’ve done the majority that way and have been getting 280–300 amplitude dial U/D if all else is in order. I’ve only replaced the ones that are broken or deformed.

[ManSkirtBrew]

The mainspring looks good to me. It does have a detached bridle. I've had trouble getting detached bridles back into the barrel in the past so I'm a little hesitant to pull it out, but I suppose it does need to be taken out to be cleaned properly.

 

Here's the hole in the barrel bridge. It does seem to have been sleeved, whether from the factory or not--I'll have to open the other one and see. Do you think closing it up with a rounded stake will still work here? Top:

 

 

Bottom:

Well, to my surprise, the watch on the right with the yellow dial started right up and runs strongly. Dial up and dial down:

 

There's almost no play in the barrel bridge. It does look like that bearing sleeve is from the factory:

 

Looks like instead of a parts movement, I've got a fine working one! Maybe I'll swap the nicer dial onto this movement. We'll see how the other one comes out.

[Nucejoe]

9 hours ago, Levine98 said:

. I’ve only replaced the ones that are broken or deformed.

Notice on the rotor it says "adjusted in six positions " this is a good grade oscilator/ watch. 

Needs a new barrel complete.

Rgds

Notice how nice dots form the line and only few dots are scattered,  thats the machine distingueshes every single tic in good order, indicating good grade hairspring/ oscilator/ escapement. 

Shame to put damaged barrel and spindle broken spring back in. 

Slight problem with one pallet though.

I plan to learn as much as I can with TG print outs, when I get a tg machine. 

Rgds

[Levine98]

Here's the bulova 23 model history I referenced above (source: NAWCC 2010 Bulletin Authored by Bruce Shawkey).

Bulova 23 History.pdf

9 hours ago, ManSkirtBrew said:

The mainspring looks good to me. It does have a detached bridle. I've had trouble getting detached bridles back into the barrel in the past so I'm a little hesitant to pull it out, but I suppose it does need to be taken out to be cleaned properly.

 

Here's the hole in the barrel bridge. It does seem to have been sleeved, whether from the factory or not--I'll have to open the other one and see. Do you think closing it up with a rounded stake will still work here? Top:

 

 

Bottom:

Well, to my surprise, the watch on the right with the yellow dial started right up and runs strongly. Dial up and dial down:

 

There's almost no play in the barrel bridge. It does look like that bearing sleeve is from the factory:

 

Looks like instead of a parts movement, I've got a fine working one! Maybe I'll swap the nicer dial onto this movement. We'll see how the other one comes out.

I normally don't take out the bridle--I just soak the barrel in napha and clean with a soft paint brush before putting into ultrasonic. Like I said, whichever one of the cases/movements you decide to not to use as a whole I'll take dibs. Jay

[dadistic]

That article by Bruce Shawkey is what got me interested in the Bulova 23's. He's a good guy, I met him when I lived in Madison WI. Unfortunately, he had a stroke a couple of years ago, and is not as active as he used to be. But, he still has a blog and writes regularly about various watch brands.

http://brucesworldofwatches.blogspot.com/

 

[Levine98]

59 minutes ago, dadistic said:

That article by Bruce Shawkey is what got me interested in the Bulova 23's. He's a good guy, I met him when I lived in Madison WI. Unfortunately, he had a stroke a couple of years ago, and is not as active as he used to be. But, he still has a blog and writes regularly about various watch brands.

http://brucesworldofwatches.blogspot.com/

 

Wow, thanks for the background. My membership in the NAWCC is about to expire and I doubt I'll renew re: I just haven't found the forums that helpful and in a couple of cases felt out of place since as a newbie I can't work a watchmakers lathe (and doubt I ever will).

I also attened the annual convention and also was not impressed enough to consider a repeat re: seemed like 80% of the attendees were clock collectors, 15% pocket watch and only a couple of wristwatch guys.

Not slamming them--just didn't work for me like this forum does.

BTW: lived 14 years in the Twin Cities before retiring to Richmond VA--best place we ever lived once we got past the weather

[ManSkirtBrew]

On 1/6/2023 at 8:26 AM, Levine98 said:

I normally don't take out the bridle--I just soak the barrel in napha and clean with a soft paint brush before putting into ultrasonic.

My concern is being able to apply fresh braking grease. There has to be a good way to get that bridle back in place.

[Levine98]

Yikes, I think I've been greasing my automatic winders incorrectly 

Edited January 8, 2023 by Levine98

[ManSkirtBrew]

Finally back to work on these guys. I cleaned and inspected both movements, and will be using almost all of the parts from the second one, which was originally supposed to be the donor.

The original shows a lot of wear and rust. The only problem with the second one is badly worn teeth on one of the automatic winding gears, but I was able to steal that from the other movement.

The mainspring looks good, but I'm going to see if I can source one easily first. For a few bucks, I think this guy deserves it. Plus then I don't have to try to get the bridle back in

[ManSkirtBrew]

Almost there! Just have to decide which case I'll be using. They both have pros and cons.

[ManSkirtBrew]

Oh I forgot to mention--for anyone trying to get a detached bridle back into the barrel.

I turned my mainspring winder upside down and carefully fed the bridle in through the slot on the side. I was able to gently slide it in by pushing with tweezers and pegwood while making sure it didn't pop out the top with a gloved finger.

It was surprisingly easy. The hardest part was all the time I spent making sure I got the hook orientation right, as well as which end would overlap the other.

Make sure your disassembly photos are better than mine! And don't forget to make sure the winder you choose for the mainspring is small enough to fit *inside* the bridle you just installed.

[JohnR725]

16 hours ago, ManSkirtBrew said:

detached bridle back into the barrel

somewhere lurking in this discussion group somebody actually had mainspring winders specifically designed to put the bridle in. Fortunately today the mainsprings are all supposed to be assembled and not require that tool.

[ManSkirtBrew]

9 hours ago, JohnR725 said:

somewhere lurking in this discussion group somebody actually had mainspring winders specifically designed to put the bridle in. Fortunately today the mainsprings are all supposed to be assembled and not require that tool.

I did consider trying to wind the bridle up with the mainspring, but that seemed even more fiddly and prone to hurting myself.

I also searched this forum but was unable to find much on the subject. Maybe next time I come across it I'll be more thorough in my searches.

[Jon]

37 minutes ago, ManSkirtBrew said:

I did consider trying to wind the bridle up with the mainspring, but that seemed even more fiddly and prone to hurting myself.

I also searched this forum but was unable to find much on the subject. Maybe next time I come across it I'll be more thorough in my searches.

I created some slides as part of a lesson I do on these types of mainsprings. The one in the slides is from a Felsa 692

[JohnR725]

3 hours ago, ManSkirtBrew said:

I also searched this forum but was unable to find much on the subject. Maybe next time I come across it I'll be more thorough in my searches

I wouldn't get too concerned about it the search on the message board sucks. Often times I Find discussions that I know exist. I think somebody basically asked why do these mainspring winders look so weird they look like the standard Swiss ones but there's something different about them and someone the conversation it came out these are for the bridal. See should bill a search for the word bridal but who knows what's going to come up. So basically sometimes finding things that exist is impossible.

Or a perfect example is the pictures up above they're not findable. This is where on the website if you had pictures are supposed to have alternative text to describe the picture which would help the search engine find it but we don't do that we upload pictures here.

oh even if you do find possibly one of the links to the discussion there is other problems like where the pictures

 

 

[ManSkirtBrew]

Good news: most of the crud on that white dial were flakes of rust. After quite a bit of quality time with the microscope and Rodico, it looks fantastic. The hands also cleaned up beautifully. Really striking in the right light.

Bad news: the seconds hand has a hitch in its giddyup. I shot a minute of video to show it.

My first thought was the pressed-on center seconds hand was pressed down too far and hitting the barrel bridge. I took it off and reseated it, no change.

I've verified that the hands are not touching anywhere in their rotation, including right at the center.

What I do notice is there's more side play than I'd expect between the extended shaft for the center seconds gear and the center wheel. The center wheel has a brass bushing that the shaft rides in, and there's a lot of play there.

My theory is the play is allowing the barrel of the seconds hand to hit the inside of the cannon pinion, which is causing that grab-and-let-go motion I'm seeing.

The thing is, the other movement has a very similar amount of play between the wheel and the shaft.

Before I go and start buying new parts, anyone have thoughts on things I might be missing?

 

[GuyMontag]

Perhaps try increasing the tension that the sweep seconds tension spring is providing on the sweep second pinion. I've never personally seen "backlash" that the tension spring is supposed to control, but what I've read makes it sound like this.

 

EDIT: was the tension spring broken? It looks like it in the movement photo but in the parts tray it doesn't

Edited May 9, 2023 by GuyMontag

[JohnR725]

On 5/1/2023 at 1:39 PM, ManSkirtBrew said:

wear and rust

rust typically comes from somewhere a combination of alloys of iron, oxygen and water. Do you know what was rusting in the watch? Then rust can make a really nice grinding compound.

6 hours ago, ManSkirtBrew said:

What I do notice is there's more side play than I'd expect between the extended shaft for the center seconds gear and the center wheel. The center wheel has a brass bushing that the shaft rides in, and there's a lot of play there.

can you see the bushing? Oftentimes the bashing can wear out especially if there was rust on the shaft. So you may have to replace one or both of those

5 hours ago, GuyMontag said:

Perhaps try increasing the tension that the sweep seconds tension spring is providing on the sweep second pinion. I've never personally seen "backlash" that the tension spring is supposed to control, but what I've read makes it sound like this.

usually when you're driving a sweep second pinion usually is a spring. This is because there is play in the gear teeth and without the spring you'll see the play exactly is what you're seeing. Possibly made it worse with the amount of play the shaft has in the center tube. So somewhere there is usually a spring and is not supposed to lubricate the spring. Where is it supposed to provide friction so that as the secondhand is being driven it's not free to flop around. So not a lot of friction just enough friction to keep the pinion from flopping around.