How to remove this c1921 Bulova balance from its cock?

[GPrideaux]

I recently acquired a Bulova/Rubiyat watch to attempt restoration as a somewhat long-term project. There are some rather obvious issues with the balance, and my first challenge is how to remove the balance from the cock.

I can see how to open the regulator, but there is no stud screw. As I see it, I have two choices:

1. Pull the pin holding the balance spring to the stud and remove the spring leaving the stud on the cock, then when it comes to reinstallation replace the pin to hold the spring in position.
2. Press the stud from the cock using an appropriate stake and stump in my staking set, then when it comes to reinstallation press them back into position.

I hope someone can tell me that number 2 is the way to go as I'm not at all optimistic of my ability to do number 1, unless, maybe, there is a tool especially for the task. And if it is number 2, is that what these stumps are for (and if not, what stumps should I use)?

[watchweasol]

Hi. I usually press the stud out of the cock. Putting it back requires the correct orientation of the spring regarding the regulator, setting the spring between the pins .

[nevenbekriev]

It looks like there is stud screw, but it has been broken. Just look from aside needed to confirm. To press out the stud, You need to support the cock at the edge of something, as the stud to be touching this edge and in the same time to be able to go down, and balance to hang free on the hairspring. Then You must press the stud with something thinner than it from above. Then You will need to etch the remain of the screw in alum or acid  solution.

[GPrideaux]

Thanks, but there is no screw. Here's a view that shows the end of the stud arm.

It has what looks like a crack, but after examining it with my stereo microscope I think is actually just a deep scratch. It's not visible at all on the underside.

[GuyMontag]

What movement is this?

[GPrideaux]

13 minutes ago, GuyMontag said:

What movement is this?

Good question! No caliber number is visible on the movement. As you can see it's a Bulova movement on a Frey ebauche. The trapezium stamp near the balance says FRECO. There is what appears to be a serial number stamped on the dial side: 147604.

The dial also gives no clues beyond the brand name Rubaiyat and the word Swiss, which together with the "Bulova W. Co" on the movement give me an approximate date. (As best I can tell, the Rubaiyat brand wasn't used after around 1921, and "Bulova W. Co" was replaced by "Bulova Watch Co" in May 1923.)

It's possible there may be some more markings hidden by bridges, but I'll be surprised if that's the case.

The case has serial number 1020981. Matching Roman numerals inside the bezel (981) confirm it as original to the case, and there is no reason I can see to suspect the movement, dial and case are not all original.

The "American Standard" brand on the case dates it to after 1 Aug 1918 and the absence of 'Bulova' on the case dates it earlier than 1925.

The lack of any caliber number or code on the movement might suggest that it is a little earlier than 1921: possibly 1920, but the presence of a movement serial number and the crown at 3 argue against it being any earlier than that.

The case is a little different (e.g. crown at 3) but the movement is the same, I think, as the one shown here: https://mybulova.com/watches/1920-rubaiyat-12103?page=1

[GuyMontag]

Interesting. I have quite a few older Bulova movements and was hoping I might have one of these but this predates any that I have.

[RichardHarris123]

[Klassiker]

The spring is fixed by a tapered pin in the hole in the stud, isn't it? That's what I'm seeing at 8 o'clock in your very first photo.

If so, you need to remove that pin, then either replace it or use a fresh one to re-pin the spring after. Firm tweezers with unequal length tips are often used to push these pins back in.

[GPrideaux]

Thank you, yes the spring is pinned to the stud. I'm optimistic I won't have to unpin/repin it. The stud is friction fit to the cock and I have been able to push it out using my staking set.

[Klassiker]

OK. I hope it goes back in as easy as it came out!

[Neverenoughwatches]

53 minutes ago, Klassiker said:

The spring is fixed by a tapered pin in the hole in the stud, isn't it? That's what I'm seeing at 8 o'clock in your very first photo.

If so, you need to remove that pin, then either replace it or use a fresh one to re-pin the spring after. Firm tweezers with unequal length tips are often used to push these pins back in.

That is how I do it, having worked on many cheap movements that have fixed studs and making hairspring repairs , you just get used to removing and refitting the brass pin. I use stiff tweezers to push the pin out, one leg is shorter with a slot in the end that straddles the pin. 

The pins aren't so bad to make either, I use copper rather than brass, from copper wire.

Edited December 28, 2024 by Neverenoughwatches

[GPrideaux]

It seems to me there are fewer variables with pushing the stud out rather than unpinning the hairspring. I dare say that's something I'll do at some stage but this movement has plenty of other issues to keep me learning (missing shellac on the pallet and broken escape wheel jewel that I know about). The hairspring will need a little adjustment, and it seems to me that will be easier to manage with the stud in place since I can position the stud on the cock and adjust the spring to sit nicely in the regulator and be centred over the jewel. I could probably do that by unpinning the hairspring, too, but the process is more familiar with the stud attached.

[Neverenoughwatches]

37 minutes ago, GPrideaux said:

It seems to me there are fewer variables with pushing the stud out rather than unpinning the hairspring. I dare say that's something I'll do at some stage but this movement has plenty of other issues to keep me learning (missing shellac on the pallet and broken escape wheel jewel that I know about). The hairspring will need a little adjustment, and it seems to me that will be easier to manage with the stud in place since I can position the stud on the cock and adjust the spring to sit nicely in the regulator and be centred over the jewel. I could probably do that by unpinning the hairspring, too, but the process is more familiar with the stud attached.

I think a lot depends on how the stud pushes out and how it pushes back in. I tend to consider that a staking tool is required to do both, I consider...will the friction fit still be the same or has it been made less and what will I need to do to make it back as it was. I also consider that the re-fit of the stud's position needs to be correct in both height and rotation in the hole and will those adjustments by stake to get the stud right be problematic in some way and loosen the friction fit further ? That all needs to be achieved while the hairspring is attached to the stud. The centering of the hairspring over the balance jewel is done with the stud in the cock, that means the stud will be removed and refitted more than once. There are pros and cons to both ways, just my preference to remove the pin .

[nevenbekriev]

There are alot of movements where the stud is tight fit in the hole of the cock. The stud has tapered pin that gets in the hole. This way of stud fixing dates from french  verge watches, and is used in huge variety of cylindre and lever movements in pocket and wrist watches. This way of fixing is for convenience, it is meant to ease the assembling and disassembling. But not staking set is needed, and I actually wonder how exactly to use staking set safely here.

[mbwatch]

4 hours ago, Neverenoughwatches said:

one leg is shorter with a slot in the end that straddles the pin

Aha! I have seen tweezers fitting this description for sale, both with a "factory look" and others with a modified/homemade look. They are often labeled as something like roller jewel or pallet fork tweezers, neither of which ever made sense based on their geometry.

[GPrideaux]

39 minutes ago, nevenbekriev said:

I actually wonder how exactly to use staking set safely here

I set the staking tool up so the stake came down just off the stump, then rested the arm of the cock on the stump while holding the other side of the cock with tweezers, letting the balance rest on the base of the staking tool, then pushed the stump down with a narrow punch, and it popped out easily. It seemed to me that it was not very much tighter than using tweezers to push out a normal stump after loosening its screw. Next time perhaps I'll try just pushing it out with tweezers.

[Neverenoughwatches]

11 minutes ago, mbwatch said:

Aha! I have seen tweezers fitting this description for sale, both with a "factory look" and others with a modified/homemade look. They are often labeled as something like roller jewel or pallet fork tweezers, neither of which ever made sense based on their geometry.

Easy to make a pair, the usual is...one long leg to push out the pin and a short leg to rest against the end of the stud.  I put a slot in the short leg so i can make the leg a bit longer that stops it slipping of the stud. One thing to watch though when pressing it out ..the brass pin can break free from the stud  like a bullet from a gun. When I'm wary of this I set up a catch for it using folded paper.

[linux]

Just pulled this from ebay:

It was listed as: pallet fork tweezers

[Neverenoughwatches]

50 minutes ago, linux said:

Just pulled this from ebay:

It was listed as: pallet fork tweezers

If they are then I dont know in what way they are used.  I have that same pair of Tissot tweezers.  Very thick and sturdy, the tips have a fork and a pin and also a pin at the end of the handle. The tips are much too big for stud pin removal,  the lateral pin in one tip would interfer with a pallet fork. I have asked before what they might be for , there was no answer.

[linux]

1 minute ago, Neverenoughwatches said:

If they are then I dont know in what way they are used.  I have that same pair of Tissot tweezers.  Very thick and sturdy, the tips have a fork and a pin and also a pin at the end of the handle. The tips are much too big for stud pin removal,  the lateral pin in one tip would interfer with a pallet fork. I have asked before what they might be for , there was no answer.

So you're saying they cannot be used to pick up a pallet fork (which is what I assumed they could do)?  Or are you saying you don't know how they could be used on the balance?

[Neverenoughwatches]

Just now, linux said:

So you're saying they cannot be used to pick up a pallet fork (which is what I assumed they could do)?  Or are you saying you don't know how they could be used on the balance?

Both. 

[linux]

1 minute ago, Neverenoughwatches said:

Both. 

Ha ha.  So I'll scratch that off of my "tools to possibly get in the future" list"

[Neverenoughwatches]

Not shown in the photo, one tip has a pin set laterally,  the other tip has the thin fork that you CAN see. The pin passes through the fork when thd tweezers are pressed together. 

[Neverenoughwatches]

Just now, linux said:

Ha ha.  So I'll scratch that off of my "tools to possibly get in the future" list"

I have actually no idea how they are used. Because they are so wide and thick I use them for checking barrel arbor sideshake and barrel pitch about its axis.