Broken pivot

[JGrainger]

When working towards a nice level of polish and fit, you really need to get a sharp edge on the graver - specifically sharpened on a fine grit - that will take away a lot of turning marks because the turned finish will match the finish on the graver. There are a few things which are recommended for polishing, usually with a couple of steps. You could rub two fine oil sharpening stones together, to create a powder which you could use on the brass sheet you are currently using behind the emery paper (with some oil mixed in). The emery paper will do something but it's not really designed for sanding something small enough to act like a knife on it.

After this a typical recommendation would be to use a clean bit of brass and oil with diamond powder - diamond lapping paste on the brass will do the same thing (which can be bought cheaply online).. When polished with the fine diamond powder and oil it should be possible to get a black finish (reflecting light or none depending where the reflection is). A soft material like brass is used so that the powder is held on the tool, becoming impregnated in the surface so you finish up with a fine cutting small brass diamond hone.

Along with this you're also working towards a size and hardened outer skin on the pivot. In practice I like to polish slightly oversize then do the last bit with a burnisher. The oil is used so that the micro-teeth on the burnisher don't clog with metal (keeping it working and preventing scratches while burnishing).)

The finish from the turning basically makes or breaks the later stages of polishing.. I dislike graver sharpening but it's necessary to do well and before absolutely necessary.. sure there was something else I was going to say but have forgotten now.

[transporter]

Cheers mate, i shape first on a diamond block, then move onto my Arkansas stones with oil, as for the pivots, I have a pivot file and burnisher but no matter what I do with the burnisher I don’t seem to be able to see a visible difference from the start to the finish.
Ive watched many YouTube videos on burnishing and people seem to take about 15-20 seconds and they are done, I guess I’m just not doing it correctly so I guess more practice required.

As for the part, well I attempted to give it more end shake but for some reason just couldn’t get a good shoulder on either pivot even with my new ground right angle graver. So I gave up and made a new one with plenty of end shake turned in from the start and good shoulders. I used brasso on pegwood and some of the wife’s nails accessories ( buffing pads etc ) to get a good shine on the pivots, ok not a Jacot tool finish but they shine and move freely in the plates.
Lines up nice with the escape wheel now and has plenty of life in it when touched with an oiler when power is on the train.

My next problem is the balance it just doesn't swing like it should, it’s got a breguet coil on it, something I’ve never bent etc so I’m not too happy playing around with it that much. 
It seems to be dragging, Ie I can move the balance round half a turn and it sits there until nudged and the same the other way, if I press down on the furthest edge of the cock it will move by itself. I’ve tried a shim but it’s still a tad stiff. Will investigate again tomorrow. 

[FLwatchguy73]

Do you have close-up photos of the balance in place? It would be helpful to see how the coils of the hairspring are laying.

[JGrainger]

2 hours ago, transporter said:

Cheers mate, i shape first on a diamond block, then move onto my Arkansas stones with oil, as for the pivots, I have a pivot file and burnisher but no matter what I do with the burnisher I don’t seem to be able to see a visible difference from the start to the finish.
Ive watched many YouTube videos on burnishing and people seem to take about 15-20 seconds and they are done, I guess I’m just not doing it correctly so I guess more practice required.

Depending on the grit of the diamond block, it may not be beneficial to use an Arkansas stone. I've not personally found that an Arkansas leaves a good finish on a staff pivot before burnishing, checking with a microscope - though they are good for sharpening.

It sounds like the new part is working better.

2 hours ago, transporter said:

My next problem is the balance it just doesn't swing like it should, it’s got a breguet coil on it, something I’ve never bent etc so I’m not too happy playing around with it that much. 
It seems to be dragging, Ie I can move the balance round half a turn and it sits there until nudged and the same the other way, if I press down on the furthest edge of the cock it will move by itself. I’ve tried a shim but it’s still a tad stiff. Will investigate again tomorrow. 

In person this sort of problem can be narrowed down with examination.. from your description it is likely to be binding balance pivots, the hairspring could be rubbing, or the lever might be interacting with the balance in a way it shouldn't.

I'd start by checking the little guard pin on the top of the lever - it's possible that it has gotten bent slightly while working on the lever - lifting the balance cock could be allowing the balance pivot to enter the wider part of the jewel and push out of the way.. a microscope is great for focusing to the depth of the part when the movement is turned sideways, assembled with just the escapement parts - it you can just focus on the necessary bit closely.

If the hairspring is dragging on something it may be due to the height of the hairspring stud where it is fastened, this might be as easy as just undoing and lowering or raising it a bit. Also check the spring is in the regulator springs, and will move up and down a little in the regulator pins when nudged while the stud is in loosely. The hairspring could be mis-shaped but eliminate the easier solutions first.

One of the balance pivots may not fit into the jewel correctly.. it could have been previously turned with an oversize pivot (length or width), a pivot may be damaged (recently or previously).

There are a few ways you can go about trying to identify the issue, depending what you're most comfortable with.

You can examine the pivots and jewels and try fitting the balance wheel on its own. If the balance oscillates freely like this (without the hairspring) then the staff and jewels may be fine. Next you can fit the hairspring back on and see if it still oscillates the same.

Personally, as you mention the hairspring I'm inclined to think you suspect that may be the source of the problem, so I'd check that the hairspring is fitting in the regulator pins and that it isn't catching on anything - if you only need to adjust the height of the stud in the bridge then that's the easiest solution.

[transporter]

FLW I will post a photo today, JGrainger, sorry I didn’t explain part of my post as best I could, I use the diamond sharpener and Arkansas stone for my gravers, not for pivot polishing. Hope that makes better sense now.
I haven’t yet run the balance wheel by itself without the HS attached, don’t know why I didn’t think of that as I’ve done it before ( brain fart) I shall do this later today. The HS stud is at a fixed height as the photo shows,  I do have a spare but it is fixed on the opposite to this balance cock, so I will have to swap the whole balance which id rather not do as all the serial numbers match on the movement I’m working on and I’d like to keep them like that. 
I have had to untwist the HS and reshape, it’s not perfect on the final coil but at the time it was time to step away from the bench and have a break so I still need to address the finer points on it so bear that in mind when addressing the picture, although I have to say I have had movements run with worse looking hairsprings than this, so although maybe a small/large factor in the non running a think it’s not the only cause.

[transporter]

Ok a bit more tweeting on the HS, now flat and  pretty much true ( professionals here hold back ).When installed firstly without spring the balance freely moves with air from the blower, so no jewel/pivot wear on the balance staff.

HS installed back on the balance and placed in movement with out the pallet in place and total free movement in all directions with no binding. 
Installed pallet and balance and same problem persists, I’ve looked with the microscope thinking the roller table or pallet fork pin (as mentioned ) might be rubbing. 
I cannot see either of them touching but saying that I cannot get a good angle to see properly, I’m looking almost straight at the roller jewel. On the subject of the roller jewel it is meant to sit between the banking pins when at rest isn’t it?? Asking as I’m head scratching now as to what is causing this problem.

I did try the other balance complete but get this, as mentioned before it is attached to the opposite side of the balance cock to the other and the roller pin sits 180 degrees opposite my one!!

Now looking at the guard pin it is in position and doesn’t look bent. So I don’t think it’s that either.
So back to looking and testing for the rest of the afternoon

[transporter]

Quick update, we have movement, dial up and pendant left and right but once dial down we stop, so time to investigate the cause of the stoppage in that position.

[transporter]

Ok then, I think I need to make another pallet fork staff, I seem to have to much end shake on this one, I thought I had but was hoping I could get away with it. So out with the lathe again tomorrow ( wife permitting as she’s working from home ) and I’ll hopefully turn another one or two or three depending on how it goes, as usual I’ll keep the thread updated with the progress.

[JGrainger]

It sounds like you're getting there, and the hairspring looks better than some I've found in running watches. Sorry for a late response, I've been busy with some other stuff lately. Let us know if the new staff sorts it out.

[jdrichard]

Ahhh now I have the bit in the bottom photo but unfortunately not the rod that attaches it to the tail stock, I also don’t have the bit in the top photo ( piece from Jacot tool ). I’ll be honest I’ve not a clue as to how those two tool bits would look like set up on a lathe, well I suppose I have but that’s besides the point and I should search myself.
I do use 3 in 1 on the burnisher but so far no shiney pivots, I do wrap a piece of 1500 wet and dry over a thin piece of brass sheet and allow the pivot to run up and down the edge but it does eat through the paper in quick time  and I can’t say that it’s doing anything to be honest. 
But I think I’m having abit more success now with the turning, here’s the second one of the day, I believe I’m almost there?????
Constructive criticism and pointers greatly appreciated, I will say the top one looks slightly different as it has a high polish on its surface. 

Here you go:

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[jdrichard]

Ok then, I think I need to make another pallet fork staff, I seem to have to much end shake on this one, I thought I had but was hoping I could get away with it. So out with the lathe again tomorrow ( wife permitting as she’s working from home ) and I’ll hopefully turn another one or two or three depending on how it goes, as usual I’ll keep the thread updated with the progress.

Good luck. I just finished on and it is too long on the Roller Table side. So need to cut back the complete cone and pivot.


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[transporter]

Cheers gents, at the moment I haven’t been at the bench, been decorating the watch/hobby and ordered a complete new bench set up from ikea, will be here by the end of next week. Will post photos for your interest.

I did try and have another go at the staff but I was on a temporary table with the lathe and just couldn’t get on with it, wrong height, light etc etc so I packed it away and will wait until my new bench arrives.

I need to get a Jacot tool, maybe? If I can get one cheap enough to warrant to buy it as this is the first real bit of pivot polishing I’ve done so I don’t want to break the bank on a tool that is going to sit around most of the time. 
Mind you a new tool!!!!!

Cant be anymore expensive than the bergeon cotton buds in the new cousins news letter £56!!!!!!!!

[transporter]

On 4/13/2020 at 3:20 PM, nickelsilver said:

I would suggest, as a former teacher, to concentrate on making nice smooth cylinders first, in unhardened steel (or even brass). Then make nice smooth cylindrical pivots (of any size) with nice square shoulders. Then try hitting a specific diameter for simple cylinders, then specific diameters for pivots. Then do the same with hardened and tempered (blue) steel. I understand making an actual part is more motivating than making "dumb" parts, but you will find that in a few hours you can reliably make those cylinders and pivots. Then making the part will be easy. Then you'll be really motivated to make all sorts of stuff.

 

The image is taken from an article in Horological Times, this shape of graver can really help to avoid undercutting a shoulder when making pivots.

 Nickelsilver, could you show me an actual phot of this graver please, I have had a go at making one but just don’t seem to be able to get an edge on it. Thanks.

On 5/8/2020 at 11:20 PM, jdrichard said:

Here you go:

 

 

 

 

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Huge thanks for the video Jdrichard I now have a Jacot tool and it’s been invaluable with my pivot work. 
i successfully made yet another staff, I think that was number 12 maybe more. Any way I have good movement on the balance but very low amplitude, I might just make another staff and see how that goes, I’m pretty good at it now.

yes you are correct for those that spotted the bent pin on the arm, it’s back to where it should be now.

i think the next one i make I will have to shorten the pivots as the lower one is a tad too long and pokes out the jewel hole, I suspect this isn’t doing the amplitude any favours either.

Anymore hints and tips appreciated, thanks guys.

[nickelsilver]

I'll post some pics when I'm back in the shop Monday.

[transporter]

Many thanks mate much appreciated, would just like to see both the face and rear so I get an idea of where I’m going wrong.

[jdrichard]

Huge thanks for the video Jdrichard I now have a Jacot tool and it’s been invaluable with my pivot work. 
i successfully made yet another staff, I think that was number 12 maybe more. Any way I have good movement on the balance but very low amplitude, I might just make another staff and see how that goes, I’m pretty good at it now.
yes you are correct for those that spotted the bent pin on the arm, it’s back to where it should be now.
i think the next one i make I will have to shorten the pivots as the lower one is a tad too long and pokes out the jewel hole, I suspect this isn’t doing the amplitude any favours either.
Anymore hints and tips appreciated, thanks guys.

No problem:)


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[transporter]

This is the pallet staff in place with both plates screwed down. A puff off my blower and as you can see it spins freely, as does the rest of the train. So I’m thinking the low amplitude is again the hairspring. It seems to be catching on itself as there looks to be a definite click to it when it’s in motion, it’s not massive but it’s visible. 
Theories and thoughts appreciated, cheers 

[transporter]

Gentlemen and ladies ( if we have any ) I do believe I have some success. A day of manipulating the hairspring and lots of coffee we have the results of my endeavours here for you to see. Thanks to everyone that gave advice and hints and tips and the asked for criticism, all very much appreciated.
There were many failed attempts at making the pallet staff and some very successful ones that I broke the pivots off when burnishing them, I have learned a lot about turning by hand on my very old 6mm Lorch lathe so I’m happy with that, even happier that I’ve also got quite handy on the Jacot tool, so another skill learned ( still a long way to go on all fronts though ) but i am after all just a tinkerer and not a skilled watchsmith. 
Enjoy my failures, there’s a picture of most of them sat in tray, I’ll keep all them as reminders that you just gotta keep trying.