Broken barrel arbor.

[Neverenoughwatches]

There's a first time for everything,  broken pivot on a barrel arbor, granted it looks quite small and feeble, in a plate jewel as well  EB 8021N . Been running like that for a while looking at the wear on the plate. Typical all cleaned and ready for assembly, new balance staff fitted trued and poise checked.  Check all the watch parts people before you start cleaning and find the irreparable repair first . Looks like me and the lathe will be getting reacquainted tonight

[nevenbekriev]

You can do it Rich, just a repivoting and the part is big.

[Neverenoughwatches]

11 minutes ago, nevenbekriev said:

You can do it Rich, just a repivoting and the part is big.

Thanks Nev,  its my first attempt at repivoting anything, but yes its big so it eases me into the operation. 

Pivot is only 0.34 thats small as far as I'm concerned

[nevenbekriev]

Go and drill with 0.4, then finally turn the piece to size untill it fits the hole. Don't worry, if something happens, You can turn new arbor.

[RichardHarris123]

I have never understood how a square can be produced on a lathe, seen plenty of videos but not sure how it works. How do you make the huck on the arbor?

[Neverenoughwatches]

0.3mm hole drilled which was surprisingly easy and went a whole lot better than i expected considering i did it free hand with a carbide bit in a small pin vice,and no breakages. I only have some 0.34mm and 0.5mm blue steel so my plan is to open up the hole to 0.5mm and reduce the pivot down to size to fit the plate bearing before fitting it in the arbor.  I'm not entirely sure on the hole depth, my head is tell me 3x the hole diameter .

56 minutes ago, nevenbekriev said:

Go and drill with 0.4, then finally turn the piece to size untill it fits the hole. Don't worry, if something happens, You can turn new arbor.

I dont have a 0.4 mm Nev or i would have.  Turn a new arbor me thinks you overestimate my ability Nev

23 minutes ago, RichardHarris123 said:

I have never understood how a square can be produced on a lathe, seen plenty of videos but not sure how it works. How do you make the huck on the arbor?

Only Nev knows that secret Rich, The only thing  i know is i wont be doing it !!

[nevenbekriev]

Now don't hurry to enlarge the hole to 0.5. Hope I am not late saying that.

[Neverenoughwatches]

Just now, nevenbekriev said:

Now don't hurry to enlarge the hole to 0.5. Hope I am not late saying that.

No i haven't started to do that yet Nev, i wanted a bit of feedback first. I think you're  going to tell me to turn the pivot hole spigot down to 0.3 , i thought that would be too small and weak though

[nevenbekriev]

Enlarging the hole is dangerous and it is almost sure that the drill bit will break inside and it will be hard or even impossible to get the broken pieces out. 3X diam is enough. Just prepare the piece that will get in the hole in a manner that it will have 0.3 X10 part that will enter the hole and wide part that will be outside and will be able to turn it tio size.

[Neverenoughwatches]

1 minute ago, nevenbekriev said:

Enlarging the hole is dangerous and it is almost sure that the drill bit will break inside and it will be hard or even impossible to get the broken pieces out. 3X diam is enough. Just prepare the piece that will get in the hole in a manner that it will have 0.3 X10 part that will enter the hole and wide part that will be outside and will be able to turn it tio size.

I knew you would say that, i was thinking the same , i wasn't particularly happy about opening up the hole. Should have gone with the 0.5mm to start.  On the positive side i now know i can drill a hole for a 0.3mm pivot, looking at it through x25 while i was drilling it looked MASSIVE

[nevenbekriev]

I think that if this is a spring wire like piano string or similar, it will not break and  wili be srong enough.

What You could do is to drill straight with 0.5 . Then it would be beter, but now it is good enough to do it with 0.3.

See, the watchmaking is actually a piece of cake, just some practice and skills to develope needed and to believe in own strenghts

[Neverenoughwatches]

1 minute ago, nevenbekriev said:

I think that if this is a spring wire like piano string or similar, it will not break and  wili be srong enough.

What You could do is to drill straight with 0.5 . Then it would be beter, but now it is good enough to do it with 0.3.

Yep my thoughts the same,  i realised i slipped up with the smaller drill half way through. Out of curiosity if you had to widen a hole, could it be plugged and re- drilled ? 

[nevenbekriev]

2 minutes ago, Neverenoughwatches said:

Yep my thoughts the same,  i realised i slipped up with the smaller drill half way through. Out of curiosity if you had to widen a hole, could it be plugged and re- drilled ? 

See, the problem with widening to a little bit wider diam is that the bit will 'grab' too much at a time and will get in too fast by itself, then it will stuck and break imediatey. If enlargening from 0.3 to 0.5 needed, complitelly different drill bit must be made - it must be similar to the ones they use for weapon cannons, with one cutting edge and with angle that will not cut fast. The other option is to enlarge the hole like they do on big lathes with cutter for internal turning, that will be small enough to get in the hole

The idea with the plugging could work, but I haven't try it. The pug should be only a little bit softer than the piece and must get in completelly to the botom of the hole.

 

[Neverenoughwatches]

13 minutes ago, nevenbekriev said:

See, the problem with widening to a little bit wider diam is that the bit will 'grab' too much at a time and will get in too fast by itself, then it will stuck and break imediatey. If enlargening from 0.3 to 0.5 needed, complitelly different drill bit must be made - it must be similar to the ones they use for weapon cannons, with one cutting edge and with angle that will not cut fast. The other option is to enlarge the hole like they do on big lathes with cutter for internal turning, that will be small enough to get in the hole

The idea with the plugging could work, but I haven't try it. The pug should be only a little bit softer than the piece and must get in completelly to the botom of the hole.

 

It wasn't a rookie mistake Nev , i should have know better with me being a joiner. After a hole another a wider bit has nothing to keep it to center and the outside of the flutes draw the drill bit in fast because of no material present. I must have done it thousands of times in timber and plastic . It was a senior moment mistake.

[nevenbekriev]

1 hour ago, RichardHarris123 said:

I have never understood how a square can be produced on a lathe, seen plenty of videos but not sure how it works. How do you make the huck on the arbor?

One way is to file it by hand. Good file with sharp edge is needed.

Another way is with the aid of milling attachment.

There is one more way, thyat is really only on the lathe, but the arbor has to be attached perpendicular to the axis of the spindle. Will be easier to show pictures than to explain this.

I must say 'Good night' as my wife is now awake and is roaring when I get closer to the computer...

[Neverenoughwatches]

16 minutes ago, nevenbekriev said:

One way is to file it by hand. Good file with sharp edge is needed.

Another way is with the aid of milling attachment.

There is one more way, thyat is really only on the lathe, but the arbor has to be attached perpendicular to the axis of the spindle. Will be easier to show pictures than to explain this.

I must say 'Good night' as my wife is now awake and is roaring when I get closer to the computer...

Besides locktite Nev, is there anything random that you use to fix in the pivot ?

[rossjackson01]

Never. Brilliant work and photographs. Thank you.

On my very first watch I knackered the arbour. I think the screw I put in was the crown screw. I didn't know about left handed screws then. Head sheared off. Thread broken just below surface. If I had the space, then a lathe would be my wished purchase. 2 1/2 years later and I still get the arbour out now and again and...... I can dream. It's a lovely pocket watch. Ah well. 

[Neverenoughwatches]

1 hour ago, rossjackson01 said:

Never. Brilliant work and photographs. Thank you.

On my very first watch I knackered the arbour. I think the screw I put in was the crown screw. I didn't know about left handed screws then. Head sheared off. Thread broken just below surface. If I had the space, then a lathe would be my wished purchase. 2 1/2 years later and I still get the arbour out now and again and...... I can dream. It's a lovely pocket watch. Ah well. 

Thanks Ross, yes i remember the broken arbor screw you had to deal with. Dont give up, if i can drill a tiny hole in a bloody hard barrel arbor without breaking the drill bit then you'll get that screw out one day somehow .

[Waggy]

Good news is that the arbour is very hard and the screws are much softer material, so drilling out is a viable option Unfortunately we can't do the alum trick.

[Neverenoughwatches]

4 hours ago, Waggy said:

Good news is that the arbour is very hard and the screws are much softer material, so drilling out is a viable option Unfortunately we can't do the alum trick.

I thought about if Ross could carefully drip alum into the hole to dissolve the screw so the outside of the arbor is unaffected.  It risks the arbor thread but with the arbor being hard and the screw is soft maybe the screw would dissolve before that happens.  Not sure if Alum reacts to the carbon content in which case the arbor has more than the screw. Re-threading the arbor would be a problem. Might be worth an experiment,  i have a few hundred random arbors, shame there isn't an arbor database like there is for staffs

4 hours ago, Waggy said:

 

 

Struggling to turn this blue pivot steel, its taking the edge off carbide, the graver isn't to the correct shape yet but it is sharp. Not sure if the square steel i have is carbide but the round is from a carbide drill bit.

Edited June 14 by Neverenoughwatches

[rossjackson01]

5 hours ago, Waggy said:

Good news is that the arbour is very hard and the screws are much softer material, so drilling out is a viable option Unfortunately we can't do the alum trick.

Can't do alum as the arbour is metal.  I did try a drill in my dremel. But was unable to hold it secure. Need a lathe. Still thinking about one of those 9 in 1 lathes on Ali. 

Edited June 14 by rossjackson01
More information

[tomh207]

1 hour ago, rossjackson01 said:

Can't do alum as the arbour is metal.  I did try a drill in my dremel. But was unable to hold it secure. Need a lathe. Still thinking about one of those 9 in 1 lathes on Ali. 

I don’t think one of those lathes would be accurate enough Ross. You would be better off with a decent vice and a good pin vice in my opinion 

 

Tom

[Neverenoughwatches]

1 hour ago, rossjackson01 said:

Can't do alum as the arbour is metal.  I did try a drill in my dremel. But was unable to hold it secure. Need a lathe. Still thinking about one of those 9 in 1 lathes on Ali. 

The alum attacks steel parts only, my thoughts were if the alum solution could be localised to the inside hole only it may break up the screw before it damages the arbor threads.  Just a thought.

[nevenbekriev]

21 hours ago, Neverenoughwatches said:

Besides locktite Nev, is there anything random that you use to fix in the pivot ?

If it is press fit will hold by itself. I put then loctite 'just in case'.

Sometimes press fit is not good idea, as the walls of the part are so thin that it will break if the pivot is pressed in. Then just tight fit is used and loctite to fix the pivot . Loctite 638 is what I use, it will harden fast if the junction is tight fit and werry slow or never if there is free play. Heating to 200 degr. celsius for a while helps to reach max strenght.

Sorry, today i was engaged and could not participate here. As I see, You have problems with the preparing of the piece?

No matter how hardened the pivot wire is, a carbide cutter will be able to cut it. Only the time when it is sharp enough to cut well will be much smaller if the wire is werry hard, than if the wire is softer.

The secret of successfull turning is that the cutter must be wery sharp and well polished. But this is not enough, as the correct position and angles against the object are of the same importance. One will need practice to find the correct position of the cutter. Looking at the pictures in the books is usefull, but one must feel the moment when the position is correct and to understand when the cutter tip breaks and learn to avoid this situations as much as possible. Do You remember how not long ago, You didn't believe that this drill bits can be used? This is the sane with the carbide cutters, I asure You that it is possible to turn hardened stil with them and soon You will be able to do this.

Must say that I don't usually prepare the piece to enter the hole by turning. I use guitar strings and have different sizes - 0.22, 0.25. 0.28. 0.3, 0.35...  I drill the hole little bigger than the needed pivot size and thus have the chance to correct eventual small centering error in drilling when turn the pivot to size. I use string that is the first in the row that will not enter the hole and reduce it's diameter by grinding with diamond disk by hand while the wire is in a pin wise. I do it in a manner that the string will get wery slightly tappered until the tip of the string will enter the hole. Then I shorten the tapered string little by little untill I get the correct size for press fit or tight fit.

 

No way to use alum on the arbor. Let me know have I correctly understand - it is piece of left-hand threaded screw that is forced in the right-hand threaded hole of the arbor?  If so, no use to try to unscrew the piece, it will not happen. Only pecise drilling of the screw piece can help.

[Neverenoughwatches]

30 minutes ago, nevenbekriev said:

If it is press fit will hold by itself. I put then loctite 'just in case'.

Sometimes press fit is not good idea, as the walls of the part are so thin that it will break if the pivot is pressed in. Then just tight fit is used and loctite to fix the pivot . Loctite 638 is what I use, it will harden fast if the junction is tight fit and werry slow or never if there is free play. Heating to 200 degr. celsius for a while helps to reach max strenght.

Sorry, today i was engaged and could not participate here. As I see, You have problems with the preparing of the piece?

No matter how hardened the pivot wire is, a carbide cutter will be able to cut it. Only the time when it is sharp enough to cut well will be much smaller if the wire is werry hard, than if the wire is softer.

The secret of successfull turning is that the cutter must be wery sharp and well polished. But this is not enough, as the correct position and angles against the object are of the same importance. One will need practice to find the correct position of the cutter. Looking at the pictures in the books is usefull, but one must feel the moment when the position is correct and to understand when the cutter tip breaks and learn to avoid this situations as much as possible. Do You remember how not long ago, You didn't believe that this drill bits can be used? This is the sane with the carbide cutters, I asure You that it is possible to turn hardened stil with them and soon You will be able to do this.

Must say that I don't usually prepare the piece to enter the hole by turning. I use guitar strings and have different sizes - 0.22, 0.25. 0.28. 0.3, 0.35...  I drill the hole little bigger than the needed pivot size and thus have the chance to correct eventual small centering error in drilling when turn the pivot to size. I use string that is the first in the row that will not enter the hole and reduce it's diameter by grinding with diamond disk by hand while the wire is in a pin wise. I do it in a manner that the string will get wery slightly tappered until the tip of the string will enter the hole. Then I shorten the tapered string little by little untill I get the correct size for press fit or tight fit.

 

No way to use alum on the arbor. Let me know have I correctly understand - it is piece of left-hand threaded screw that is forced in the right-hand threaded hole of the arbor?  If so, no use to try to unscrew the piece, it will not happen. Only pecise drilling of the screw piece can help.

Thanks Nev , i really appreciate all that information you have given me. Yes i fully understand what you say about the sharpness and approach angles for the gravers and developing a feel for the cut. I used to turn timber years ago the principles are similar especially aquiring the feel for turning. I think now that the graver was not sharp enough. I play the guitar so I may try your method with the guitar strings , thanks again Nev