Balance staff replacement

[graemeW]

Attempting my first balance staff replacement bit have a couple of questions.

Firstly, I paid  o attention when I took the roller table off. I assume it doesn't actually matter where it goes back on, it may just effect poise right?

Secondly, I've seen professionals just knock the staff out with the staking set, but I've seen other things that say the wheel needs to be clamped between 2 pieces to stop it warping. I just bought a star staking set but I don't jave the extra accessory to clamp the wheel. I've seen them, but don't have one. Is it safe to just carefully tap the staff out anyway?

Pic of my new staking set as it's a bit of a milestone purchase in the hobby

[watchweasol]

Hi. Just knocking the staff out can distort the balance wheel, professionals either use a plattax tool designed for the job or use a lathe to cut away the rivit from the staff or cu away the hub whatever your preference there are K & D tools to fit reg staking tools that do the job of the platax tool but picking up the correct size can be a lottery, I must confess I have removed the odd staff by knocking it out carefully without damaging the balance sheet. I always note the position of the inplulse pi and roller position normally at right angles to the arms and also thr stud position on the balance wheel rim for re assembly of the balance, best to tale a picture of it as is before dismantling.

[graemeW]

2 minutes ago, watchweasol said:

Hi. Just knocking the staff out can distort the balance wheel, professionals either use a plattax tool designed for the job or use a lathe to cut away the rivit from the staff or cu away the hub whatever your preference there are K & D tools to fit reg staking tools that do the job of the platax tool but picking up the correct size can be a lottery, I must confess I have removed the odd staff by knocking it out carefully without damaging the balance sheet. I always note the position of the inplulse pi and roller position normally at right angles to the arms and also thr stud position on the balance wheel rim for re assembly of the balance, best to tale a picture of it as is before dismantling.

I planned to take a pic, but I'd made a tool to take the roller off and was so caught up in What I was doing, I completely forgot.

I know about platax, and using a lathe, but neither of those are going to happen.

The k&d would be good, but I never see them for sale. The unrah max would be good too. But unless I wait for ever for one of these things to come up for sale, I don't really have any choice.

If punching out the staff without is a BIG risk, I'll see of I can make something to clamp the wheel. As I say though, I've seen video of professionals who just put the wheel on the staking anvil and punch it out.

My balance wheel is bi metal if it matters

 I assume the middle is steel, the outer is brass.

[watchweasol]

Like I said I have done it with no problems.  You could try to make a tool  like a bolt drilled out to fit the punches. Usually 4.7 mm and use that in the same manner as the k&d tool to hold the arms flat .

[mbwatch]

The K&D #50 staff remover tool is commonly for sale, between $75 and $100 usually unless you get lucky. But they come in different lengths, to fit the space between your staking die plate and the tube the punch passes through. If you buy one, you must make sure it comes with its requisite punch.

There is another tool like the Kirk's tool here, used in the manner of the Unruhmax: https://daveswatchparts.com/BalanceStaffRemovers.html Dave has them priced kind of high, and if you can find one on ebay it will be much less - maybe not even $20. Not as good as the K&D 50 but better than nothing.

Being honest though, your first staff replacement is not going to be perfect anyway. It is true that you'll see pros just knock a staff straight out. If the balance has not had multiple staff replacements before, each punching out and widening the hole, you are probably not going to cause enough distortion to the hole that your new rivet won't hold. But if you hit it too hard without enough support under the balance arms, you do run a risk of dishing them upward.

Edited February 15 by mbwatch

[graemeW]

9 minutes ago, mbwatch said:

The K&D #50 staff remover tool is commonly for sale, between $75 and $100 usually unless you get lucky. But they come in different lengths, to fit the space between your staking die plate and the tube the punch passes through. If you buy one, you must make sure it comes with its requisite punch.

There is another tool like the Kirk's tool here, used in the manner of the Unruhmax: https://daveswatchparts.com/BalanceStaffRemovers.html Dave has them priced kind of high, and if you can find one on ebay it will be much less - maybe not even $20. Not as good as the K&D 50 but better than nothing.

Being honest though, your first staff replacement is not going to be perfect anyway. It is true that you'll see pros just knock a staff straight out. If the balance has not had multiple staff replacements before, each punching out and widening the hole, you are probably not going to cause enough distortion to the hole that your new rivet won't hold. But if you hit it too hard without enough support under the balance arms, you do run a risk of dishing them upward.

It's dishing them upwards I'm concerned about.

I had noticed that there seems to be quite a few balance staff removal tools for sale in the US, but here in the UK, they seem quite uncommon. Or at least not sold often.

The pics on that site will help me make something though.

I did try to make something today but I over complicated the design and it didn't work out. My lathe is in the garage and by the end of it my hands were so cold I couldn't feel them, so I gave up.

I'll try again tomorrow.

[nevenbekriev]

Read this thread, all of it

[graemeW]

54 minutes ago, nevenbekriev said:

Read this thread, all of it

That was extremely helpful, thanks.

I think I'll grind the hub off, seems like the easiest and safest option.

[Neverenoughwatches]

11 hours ago, graemeW said:

That was extremely helpful, thanks.

I think I'll grind the hub off, seems like the easiest and safest option.

After 4 years of punching out staffs , I decided to cut hubs off, it's not difficult after a little practice . Cutting the hairspring side means trying to dig out the rivet...the hub is easier and safer to cut,  then the wheel just pulls away from rivet. 

[graemeW]

1 hour ago, Neverenoughwatches said:

After 4 years of punching out staffs , I decided to cut hubs off, it's not difficult after a little practice . Cutting the hairspring side means trying to dig out the rivet...the hub is easier and safer to cut,  then the wheel just pulls away from rivet. 

I had seen about cutting the rivet side in a lathe, and to be honest, I thought that seemed like a terrible idea. I then sort of dismissed the whole cutting it out situation.

As soon as I saw someone say cut the hub side, i thought that seemed like the way to go. Can't believe it didn't occur to me earlier.

[Neverenoughwatches]

3 hours ago, graemeW said:

I had seen about cutting the rivet side in a lathe, and to be honest, I thought that seemed like a terrible idea. I then sort of dismissed the whole cutting it out situation.

As soon as I saw someone say cut the hub side, i thought that seemed like the way to go. Can't believe it didn't occur to me earlier.

Sometimes the simplest of ideas passes us by.

[graemeW]

I ground off the hub, did it semi free hand. Nerve wracking, but worked well.

Been fitting the new staff and have a couple of questions.

I used the holed domed punch, the smallest one that would fit. All good.Then I used a flat holed punch to flatten it out. 

It's all gone ok so far but am unsure if I've riveted it enough. It feels stable and tight but the old staff rivet was flush with the balance arms, this one is a tiny bit proud. Wary of hitting it too hard. Should I try and squash the rivet more?

Secondly, the arms of the balance wheel were always slightly tweaked. They don't like up perfectly. It looked a little worse once the staff was out, and now the new staff is in they have gone back to how they were. I figured id wait until the staff replacement was fone before i worried about this.

Can i/should I gently tweek this after to get them true to the wheel?

That pic makes it look worse than it is, I tried to get an angle that showed it as bad as possible so you can see what I mean.

On a similar subject, checking for wobble, I assume my best bet is to just put it in the bare main plate with its cock and spin it? Without proper tools, I can't think of a better way.

 

 

[AndyGSi]

2 hours ago, graemeW said:

It feels stable and tight but the old staff rivet was flush with the balance arms, this one is a tiny bit proud.

Are you sure it's the correct staff?

Did you check the old against the new?

[graemeW]

12 minutes ago, AndyGSi said:

Are you sure it's the correct staff?

Did you check the old against the new?

It's for this movement 

As much as I could. Its the same length, the roller part and spring collet areas are the same, the wheel was a nice snug fit on the staff like the old one was. I think if there had been less rivet sticking up, I wouldn't have been able to rivet it.

I think the wheel would have felt tight on the staff even before riveting so I'm just unsure if I should try and knock the rivet down more.

The old one was no doubt the original, the new one is ronda, so it's not going to be identical in every way.

Edited February 16 by graemeW

[AndyGSi]

28 minutes ago, graemeW said:

It's for this movement 

What movement is it and what staff did you get?

[graemeW]

14 minutes ago, AndyGSi said:

What movement is it and what staff did you get?

A favre 13 ligne from 1916, I got ronda 1296

I'm wondering if the rivet being slightly proud is normal in general, or if it's a sign I need to rivet it more. The hair spring collet being a fraction of a mm higher shouldnt matter.  I don't know if it's something I should even be thinking about, or if as long as the wheel is tight, it doesn't matter. 

[nevenbekriev]

OK, You don't have to worry that the rivet is slightly proud. You can grasp the hairspring seat in pin vise and try to turn the balance arm against the staff - it should not happen.

Truing the balance wheel is next operation after staff riveting. Yes, You must tweak the balance to get the halves in one plain. But, the wheel must rotate true, so tweaking is to be done as to achieve so. In compensating (cut) balances, truing is separately for one half and the other. And, the best practice is not to force the place of riveting the staff, but grasp the arm near the staff rivet wit specially designed pliers that will allow bending of the arm, or use the staking set with big hole punch and anvil to fix the balance around the staff by pressing the punch from above ad thus to bend the wheel in order to make it rotate true.Yes, You can put the balance in it's place to check how it turns, but it will be much harder to take it out and put it back a lot of times than using truing calipers.

Edited February 17 by nevenbekriev

[graemeW]

1 hour ago, nevenbekriev said:

OK, You don't have to worry that the rivet is slightly proud. You can grasp the hairspring seat in pin vise and try to turn the balance arm against the staff - it should not happen.

Truing the balance wheel is next operation after staff riveting. Yes, You must tweak the balance to get the halves in one plain. But, the wheel must rotate true, so tweaking is to be done as to achieve so. In compensating (cut) balances, truing is separately for one half and the other. And, the best practice is not to force the place of riveting the staff, but grasp the arm near the staff rivet wit specially designed pliers that will allow bending of the arm, or use the staking set with big hole punch and anvil to fix the balance around the staff by pressing the punch from above ad thus to bend the wheel in order to make it rotate true.Yes, You can put the balance in it's place to check how it turns, but it will be much harder to take it out and put it back a lot of times than using truing calipers.

Thank you for the advice, I'll carry on with this later today