balance staff fit

[arron]

Hi guys,

Before I drive the balance home onto the staff i'd like to make sure i have a correct fit.  I laid the balance wheel on both the old and new staff and on both there is a gap between the staff hub and the balance; i knocked out the old balance.  is there supposed to be a gap or should the balance be resting on the staff hub at this stage; to next be riveted into place?  Thanks for any input.  Arron.

[JohnR725]

Always nice if we had details like which watch which staff?

Then know that is not correct. The balance wheel should fit all the way down to the hub Otherwise if you have to pound it into place you're going to to start the balance hole or conceivably distort the whole arm. So it's supposed to drop in the place with minimal just pushing it down it should be up as high as this is.

[arron]

i had every intention to include the watch specs but then forgot so thanks for the reminder. Waltham serial 4783027; model 1888 16s 7j.

if the balance is supposed to sit on the staff hub without force, then maybe i distorted the balance hole when driving out the staff.  is there a fix to get the balance seated without force, like maybe using a round or triangular broach; i have those.  here's another pic from the top of the balance.

[JohnR725]

36 minutes ago, arron said:

like maybe using a round or triangular broach;

It's usually not recommended to modify the item you're inserting a part into. This is because it's best to keep the original part original and modify the part to fit not the other way around.

37 minutes ago, arron said:

4783027

https://pocketwatchdatabase.com/search/result/waltham/4783027

Where did the staff come from and what is the number of the staff?

[Neverenoughwatches]

42 minutes ago, arron said:

i had every intention to include the watch specs but then forgot so thanks for the reminder. Waltham serial 4783027; model 1888 16s 7j.

if the balance is supposed to sit on the staff hub without force, then maybe i distorted the balance hole when driving out the staff.  is there a fix to get the balance seated without force, like maybe using a round or triangular broach; i have those.  here's another pic from the top of the balance.

If you are talking about broaching out the hole of the balance wheel then i would say definitely not.  That is something that is going to be impossible to correct for you. I always think, if  in doubt then dont do anything. 

1 hour ago, arron said:

i had every intention to include the watch specs but then forgot so thanks for the reminder. Waltham serial 4783027; model 1888 16s 7j.

if the balance is supposed to sit on the staff hub without force, then maybe i distorted the balance hole when driving out the staff.  is there a fix to get the balance seated without force, like maybe using a round or triangular broach; i have those.  here's another pic from the top of the balance.

Verifying the issue is the first step in rectifying the issue. How much can you magnify the balance wheel hole to check for distortion? 

[arron]

thanks guys.  i checked the hole under magnification and it doesn't look distorted to my eyes.  i used a stake to gently put the balance on to where it sticks to the (old) staff but isn't all the way down; i'm fearful to drive it down until i figure out what the best course of action is.

the staff i ordered is the 2844.  i had previously ordered one from ofrei, and posted about it, but the hub was a different thickness so it couldn't be used.  the current one seems to be the right one; ordered from Daves.  

at this stage i think i either go forward with staking the balance onto the new staff (and hope it goes on without distorting the balance) or i could use my lathe for the first time and try to skim off just a bit of the circumference of the staff (after practicing on the old staff).  Thoughts?

[JohnR725]

One of the most important things to do when changing balance staffs is always measure the old staff with a micrometer preferred and measured the new balance staff and make sure all the dimensions exactly agree. Sometimes some of the aftermarket staffs were deliberately made over size at least that's. I have so that they can be reduced to fit. At least that's the only reason I can see why you make a staff over size. I remember in the case of a Hamilton 992B with the staff would not go on and to the best of my knowledge there's only one balance staff for that watch its friction staff at Apsley has to fit and it absolutely did not. That is because measuring it was found not to be the correct size and that was the aftermarket staff not an original staff

3 hours ago, arron said:

(and hope it goes on without distorting the balance)

Yes that's an interesting aspect. I miss skip over what I think of that

normally the balance wheel should fit there may be a little bit of a flat punched just to tap it down the make sure it's actually in place but it shouldn't be a friction fit at the point of risking distortion of the arms.

Then out of curiosity how did you remove the old staff?

3 hours ago, arron said:

2844.

The reason I wanted this is so I can look up the specifications also to see if there was any variations. Often times with watches there can be variations for the exact same part number dimensions will be dramatically different but it appears to be there is only one balance staff that fits this and only one set of dimensions for the most part. I have the dimensions below you can measure both your old staff from the new staff and make sure they were see if they agree with dimensions I have for the specifications.

But if you have a lathe then definitely modify the staff fits the problem comes when you modify things because you think the balance staff is right that you never measured the new one and maybe is bigger and now if you get original staff it's never going to fit every again because you modified the part for something that wasn't right. So someday someone else will attempt to replace the balance staff enough to have the right one of course now your whole is too big because of the sort of thing which is why typically never modified to fit replacement parts.

[Neverenoughwatches]

4 hours ago, arron said:

thanks guys.  i checked the hole under magnification and it doesn't look distorted to my eyes.  i used a stake to gently put the balance on to where it sticks to the (old) staff but isn't all the way down; i'm fearful to drive it down until i figure out what the best course of action is.

the staff i ordered is the 2844.  i had previously ordered one from ofrei, and posted about it, but the hub was a different thickness so it couldn't be used.  the current one seems to be the right one; ordered from Daves.  

at this stage i think i either go forward with staking the balance onto the new staff (and hope it goes on without distorting the balance) or i could use my lathe for the first time and try to skim off just a bit of the circumference of the staff (after practicing on the old staff).  Thoughts?

Erm no, i wouldn't force the balance wheel down and hope everything will be ok. For starters John will tell you off when you come back to report something went wrong, he's already in the position of not telling you his thoughts on that idea so thats kind of a good clue thats its a bad idea . Follow the course of action laid out Aaron, verify then rectify

[arron]

3 hours ago, Neverenoughwatches said:

For starters John will tell you off when you come back to report something went wrong, he's already in the position of not telling you his thoughts on that idea so thats kind of a good clue thats its a bad idea

I got a good chuckle out of that; thanks I needed it.  john lives in my neck of the woods so I'm sure he would have politely told me off  .

I used the k&d balance staff remover in my staking set to remove the staff.  I know some folks cut the rivet out on the lathe, but I've yet to use the lathe I have and didn't feel up to the challenge to start here.

  I measured both staffs at the balance shoulder and got 1.25 mm plus a few thousandths.  

[JohnR725]

6 hours ago, arron said:

I used the k&d balance staff remover in my staking set to remove the staff.  I know some folks cut the rivet out on the lathe, but I've yet to use the lathe I have and didn't feel up to the challenge to start here.

Basically it sounds like what I do. Normally lie time I worry about cutting anything is if we go to drive it out and you tap it with a very light hammer it doesn't want to come out then I worry about cutting. When I was in school the instructor George would usually just weaken the rivet by basically getting a little almost like dust on the graver not very much cutting at all.

Oh is what you get some practice practice cutting the hub off. When is teaching at the school the other instructor was big on cutting the hub off and my objection to this is it's really hard to see where the hot Ms. and where the arm is and it's really easy for well does the arm really have to be flat? Even the same on the rivet side if you're not careful so usually when I would weaken the rivet I would cut more into the staff to stay away from the arms if I ever had to do it which is almost never

6 hours ago, arron said:

I measured both staffs at the balance shoulder and got 1.25 mm plus a few thousandths. 

That looks like the specifications so it should be the right staff. You do get as I mentioned before you can get variations and aftermarket staffs can vary a little bit but should be right should bill use a flat punch to gently tap it in place hopefully without too much Being otherwise you'll tend to distort the arms again and it's not fun straightening out the balance wheel together all flat. Getting balance wheels flat is my least favorite thing to do I can usually eyeballed to get things in the round but flat that seems to be a pain

[Neverenoughwatches]

8 hours ago, arron said:

I got a good chuckle out of that; thanks I needed it.  john lives in my neck of the woods so I'm sure he would have politely told me off  .

I used the k&d balance staff remover in my staking set to remove the staff.  I know some folks cut the rivet out on the lathe, but I've yet to use the lathe I have and didn't feel up to the challenge to start here.

  I measured both staffs at the balance shoulder and got 1.25 mm plus a few thousandths.  

Best to start off using your lathe for bigger and softer things ( marsh mellows comes to mind but thats only because I'm  hungry) brass rod would be a good start so as just to gdt a feel for the process and using gravers. Same as John just for my own curiosity i checked the size of the wheel seat and it should be 1.25mm, the database does not list any orher variations. I think after inspecting both the wheel side of the staff hub for any anomalies and both sides of the wheel's surface you should be good to go.  If its tight going on i pretty much think you will know when to stop and rethink. If the fit is good it usually does push home with just finger pressure on the stake,with the ones I've done anyway. Which is only about half a dozen on projects and maybe 2 dozen practices so by no means an expert on this.

Edited June 28, 2023 by Neverenoughwatches

[JohnR725]

4 minutes ago, Neverenoughwatches said:

Same as John just for my own curiosity i checked the size of the wheel seat and it should be 1.25mm, the database does not list any orher variations

Oh that? Yes there does appear to be one and only one staff whereas typically there is not one staff typically there's variations. Typically even if it says one staff there may be variations. But seeing as how his old versus new measures the same then the old versus new chipset.

But what if we look at a different reference? Then the other references a cross reference guide they go through a list they basically measured a whole bunch a balance staff so they have a book that missteps by size and then in the back as a whole bunch a technical information from various companies and then much farther back dimensions of some balance staffs with I don't think it explains where the dimensions come from. Other than basically somebody measured staffs.

So in addition to the one listing where we only have pivot variations which is typically a really good listing can they do list all the other variations except in this case now we have four more different staffs with all slight little variations because typically there's always variations.

15 minutes ago, Neverenoughwatches said:

If its tight going on i pretty much think you will know when to stop and rethink.

This is where we have an interesting problem original staff seems to match the dimensions at least one of them of the replacement staff which seems to match the dimensions of the various listings I have sort of. This is where having access to a watchmaker's lathe with skill sets is nice because if we look at all of the images there does appear to be hobbit size variation. It suggested whoever replace the staff before probably use the same wrong staff is what you currently have. So if you are good with your lathe which are not as you haven't practiced you could take a header off the side of the staff and now not have issues. It's like that take very much you don't what it loose but you really don't want to have to this isn't a friction fit staff

Then yes they do have friction fit staffs for other watches as one of things I looked them up and yes the friction fit staffs have variations I have one on the bench were had to go through all the various assortments to see if I can find a staff that would fit because even though they were the right staff they didn't want to fit. Then I found the staff to fit the blue hop that it goes into but the roller table doesn't fit then conveniently at work I don't have the collet to spin the whole thing and knock down the size just a hair which is reminding me I need to go find my lathe collets and take them to work it's always a pain when I don't have certain things at work. But I'd much rather reduce the staff then the part and then somehow managed to get the right staff and then find that everything doesn't fit because it's now been modified to something that was not right

 

 

 

[arron]

I am very happy and relieved to report that I was able to fit the balance onto the new staff.  I used a flat stake with a hole and used just moderate hand pressure.  Now on to the rivet.  Thanks guys for all the encouragement.

I attempted to make the rivet.  I'm not sure what it is supposed to look like after riveting.  I tapped with the domed punch first and then the flat punch.  the staff does seem to be gripping the balance when i try to hold the staff with the tweezers and rotate the balance with my finger. What do you think?

[arron]

Might someone have a close-up photo of a riveted balance staff for comparison to mine?

[JohnR725]

On 6/28/2023 at 2:44 PM, arron said:

I tapped with the domed punch first and then the flat punch.  the staff does seem to be gripping the balance when i try to hold the staff with the tweezers and rotate the balance with my finger. What do you think?

Usually what you do is first with a flat punch you just make sure the balance is down tight on the staff then with a series of rounded nose punches starting from the center and pushing the rivet out. But it all depends upon the particular staff some you might not have to have so many punches it just depends on the particular staff then once it's down nice and tight you think it's tight then you follow up with a flat punch to make sure the rivet is down flat

then how tight is tight? Tweezers I don't think you do it when I was in school we grab the staff for the pin vice and we put something on the other end like a little piece your sticky clay or will piece of pith wood because you don't want to damage the pivots but something on the other side so you can see if you rotate So you hold the balance wheel in one handy rotate the pin vice and it rotates is not tight enough.

Then if you're concerned about holding to type with the pin vice start with a balance wheel you don't care about grab it tight and see what happens

then you go onto the next phase of making sure the balance wheel is still flash and round typically on a bimetallic balance wheels it will get out of both of those especially depending upon how aggressive you were taking the staff out.

I find books are handy like the website below.

Scroll down the list of all the nifty stuff you can download until you get the following at the minimum these things

1945 TM9-1575 War Department Technical Manual    Just a really good book on watch repair a must have

Then

Joseph School of Watch Making  Notice it's in sections notice the very beginning it talks about putting a staff in but scroll to the bottom of the list of the various chapters and just download the entire book it's well worth it.

https://www.mybulova.com/vintage-bulova-catalogs

 

[arron]

I tried using the pin vise as you suggested and it seems tight, so i'll consider the operation a success.  thanks for the idea and for the catalogs link.  i have a couple of them but there are many more that i've never seen.