Barrel Bushing

John P

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If you have a Sherline mill, that job can be done quite easily. If not, you may need to source that out. David LaBounty does great work and is affordable.
 

shutterbug

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I do them on my bushing machine. Bergeon makes (or at least they did) an adapter just for that purpose.
 

R. Croswell

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A spring barrel can easily be bushed using a lathe. Regardless of the method used the most important thing is to center the hole. Sometimes the arbor can be sleeved instead of bushing the barrel, but the hole in the barrel still needs to be true to center.

RC
 

Altashot

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Since barrels revolve upon their arbours, they do not wear into the egg shaped holes we see on other pivots.

It is to be assumed that the wear is even all around the hole, therefore, the hole should still be centred, only oversized.

Following this logic, and the fact that I don’t like to install such large bushings in thin walls, and that the brass has already been naturally work hardened, I normally prefer to sleeve the arbour whenever possible.

It makes for an invisible repair that, I believe, will outlast a bushing.

I also work with Sherline now, but I used to do it with my Webster-Whitcombe...It just took longer.

M.
 
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MuensterMann

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Since barrels revolve upon their arbours, they do not wear into the egg shaped holes we see on other pivots.

It is to be assumed that the wear is even all around the hole, therefore, the hole should still be centred, only oversized.

Following this logic, and the fact that I don’t like to install such large bushings in thin walls, and that the brass has already been naturally work hardened, I normally prefer to sleeve the arbour whenever possible.

It makes for an invisible repair that, I believe, will outlast a bushing.

I also work with Sherline now, but I used to do it with my Webster-Whitcombe...It just took longer.

M.
Is there a description/procedure on how to do this - as I have some wobbly barrels to take care of, and I am looking to buy some equipment and learn the procedure? Thanks!
 

R. Croswell

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Since barrels revolve upon their arbours, they do not wear into the egg shaped holes we see on other pivots.

It is to be assumed that the wear is even all around the hole, therefore, the hole should still be centred, only oversized.

Following this logic, and the fact that I don’t like to install such large bushings in thin walls, and that the brass has already been naturally work hardened, I normally prefer to sleeve the arbour whenever possible.

It makes for an invisible repair that, I believe, will outlast a bushing.

I also work with Sherline now, but I used to do it with my Webster-Whitcombe...It just took longer.

M.
I'm currently working on a clock that has a Hermle 141-020 movement 1997. The most significant issues were badly worn spring barrels. The time side was the worst and had even peeled off a brass burr that can be seen in the photo. The strike side barrel had significantly less wear. I elected to bush the time side barrel and sleeve the strike side arbor. Note that this is not a valuable clock, the movement cannot be seen, and the outcome objective was to restore reliable operation, not do an invisible repair. I do not like to install large straight bushings in thin sections like this so I made the bushing with a flange. Both barrels were mounted on an independent 4-jaw chuck on my Craftsman branded Sherline lathe and centered using a dial indicator. While the holes in the barrels were not worn "egg shaped" for the reason Altashot described, they were worn quite off center, especially the time side which had the most wear. I used a small boring bar in the lathe to enlarge the holes just enough to make them true. That necessitated that the time barrel be bushed, but I was able to just sleeve the strike side arbor.

I can't explain all the force dynamics involved that caused the off-center wear, but I believe it is related to the main spring being anchored to one side of the barrel which would seem to constantly be pulling the barrel toward that side. My observation in this example seems to support that theory. The takeaway is that when bushing a spring barrel one cannot assume that the worn hole is centered, even if it is not egg shaped as would be the case with a typical pivot hole.

I thought Hermle stopped plating pivots, but the arbors in these barrels are plated and the plating was worn through which seems to be what precipitated this failure. They also used steel barrel covers with these plates steel arbors. I guess it is supposed to be a throwaway movement for an inexpensive clock.

RC

barrels-1.jpg barrels-2.jpg
 

Dave T

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Don't want to sidetrack this thread. And I did some searching before I asked, but what does the Bergeon attachment look like for bushing barrels?
 

R. Croswell

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Don't want to sidetrack this thread. And I did some searching before I asked, but what does the Bergeon attachment look like for bushing barrels?
It looks like this: Mainspring Barrel Bushing Tool Adapter
It just holds the barrel and centers on the existing worn hole. I don't see any way that it can verify or correct an off-center hole.

RC
 
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Altashot

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Nice work RC,
Even though I agree that the hole can be slightly off centre, for what I have seen, it is not very significant.
I've checked the concentricity of new barrels and found them to be out a bit too, so it seems that it is not
a big issue, at least, not right at the power source.

I do like however how you bore the hole to be perfectly cencentric using an indicator and a 4 jaw chuck.
Whether you bush or sleeve, I believe the way you repair them actually exceed factory standards.

I will follow your method next time I need to bush or sleeve a barrel.
Although I don't see them too often as I seem to mostly work on weight driven movement,
I will take the 4 jaw chuck out for a spin.

I am always opened to new ideas, tricks, tips or methods.
25 years in the biz, and still looking to grow and to improve my methods.

Grow and learn always.

Thank you.

M.
 

R. Croswell

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Nice work RC,
Even though I agree that the hole can be slightly off centre, for what I have seen, it is not very significant.
I've checked the concentricity of new barrels and found them to be out a bit too, so it seems that it is not
a big issue, at least, not right at the power source.

M.
Quality and precision seems to be something that for many Hermle movements seems to be out of reach. It may be of significance, I believe the time side spring appeared to have been a recent replacement, and perhaps les concentric. I didn't measure the runout of the hole in the time barrel but believe it was close to 0.010". The strike side would probably have been OK with just the sleeve. I believe the important consideration is that it is just as easy to bore the hole true as it is to just ream and take a chance.

RC
 

Royce

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NO Date:???:??
I have a sherline
Based on "Dating French Clocks Using Physical Parts – Suspension, Striking, and Exposition Medaillions" by Scotty Dean; the patent date for the spring shoulders that offers the ‘click’ when adjusting was 1865, which would set your Not Earlier Than date. They also indicate that after 1880, the french used rack and snail instead of the previous used count wheel so the Not Later Than date may be approximately 1880.
However, they also provide:
MOUGIN, AD
TWO MEDALS (deux medailles)(years?) From Allix – J. Tripplin’s account of the Paris Exposition Universelle 1889: “…The production of both the Marti do not compare, as far as quantities are concerned, with that of the above mentioned firm (MM. Japy), but what they exhibited showed greater attention to rather superior work; so do the exhibits of MM. Megnin and A. Mougin, although in a lesser degree.” Estimated dates = 1880 to 1900. Live Auctioneers: “the interior backplate touchmarked "A.D. Mougin/Medaille d'Or"”
I'm not sure the info on the medals really pin anything down. To me a reasonable estimate would be between 1865 - 1880. Hope that helps.
 

Jerry Kieffer

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Is there a description/procedure on how to do this - as I have some wobbly barrels to take care of, and I am looking to buy some equipment and learn the procedure? Thanks!
Muenster
I am making the assumption you wished to see an example on how to sleeve an arbor. If not, disregard.

(1) I mount the barrel in the lathe and adjust until it runs true if required.

(2) I then bore the barrel hole just enough to assure that it is round and centered per first photo.

(3) I then machine the arbor down about .025" second photo arrow.

(4) From this point, I machine a very tight friction fit thick walled bushing per second photo and drive/press it on to the arbor. Its nearly impossible to friction fit a thin walled bushing.

(5) I then machine the bushing down to required size to fit the barrel and burnish/polish as required.

Jerry Kieffer

fullsizeoutput_432.jpeg fullsizeoutput_69a.jpeg
 
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MuensterMann

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Thanks Jerry! Good assumption!! There is much for me to learn! One item I will need to learn more as well is the use of an indicator to show if I am centered using a 4-jaw holder.
 

Altashot

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Jerry, I see from your pictures that you use a 3 jaw chuck.

Is yours precise enough or do you have run out?
Do you use your indicator on the teeth and average the high and lows?
What if the barrel is out of round, like most of them are?
Doesn't the mere pressure of the jaws squeeze or pull it out of round?
I'd be inclined to use a 4 jaw chuck for this but it's a pita to set up,
is the 3 jaw good enough?

Sorry for all the questions but I am quite new to Sherline and I am trying to up my game as well as expand
my abilities. I am not a machinist by any means, but I do have experience with much larger lathes and mills.
The work I did on them did not require the same tolerances that clocks require. I worked with my watchmaker's lathe for clockwork for years holding gravers,
and obtained excellent results, but now, I found myself using my Sherline more and more.

M.
 

Rod Schaffter

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Won't the use of a brass arbor sleeve result in greater wear to the barrel, since it is brass on brass?
 

Jerry Kieffer

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Jerry, I see from your pictures that you use a 3 jaw chuck.

Is yours precise enough or do you have run out?
Do you use your indicator on the teeth and average the high and lows?
What if the barrel is out of round, like most of them are?
Doesn't the mere pressure of the jaws squeeze or pull it out of round?
I'd be inclined to use a 4 jaw chuck for this but it's a pita to set up,
is the 3 jaw good enough?

Sorry for all the questions but I am quite new to Sherline and I am trying to up my game as well as expand
my abilities. I am not a machinist by any means, but I do have experience with much larger lathes and mills.
The work I did on them did not require the same tolerances that clocks require. I worked with my watchmaker's lathe for clockwork for years holding gravers,
and obtained excellent results, but now, I found myself using my Sherline more and more.

M.
Altashot
Very good questions.

When mounting work in a three jaw chuck, one will always get some deviation in accuracy for many reasons. Over time you learn to clean your chuck and remount to achieve the required accuracy.

When touching up a barrel with a small sharp boring tool, the result is little of any stress on the barrel. Thus tightening the chuck to the point of barrel distortion is not required or desired.
I prefer the mounting method shown in the first photo because it allows me to clearly observe the touch up process. In this case, once mounted, I position the back side of the lathe tool next to the barrel per the first photo and place a white sheet under it. From this point, I can observe runout if there is any by comparing the slow rotation of the barrel to the back side of the lathe tool under a loupe. If there is runout, I tap the barrel with a small plastic hammer one way or the other to eliminate it under loupe observation.

If the barrel is distorted, I install the barrel cover and mount in the chuck per second photo and repeat the process.

If heavy machining is required, the barrel is mounted per the third photo. If extreme accuracy under or not under heavy load is required, the barrel is mounted in machinable jaws where runout will be no greater than spindle bearing runout.

Jerry Kieffer

fullsizeoutput_6a1.jpeg fullsizeoutput_6a2.jpeg fullsizeoutput_6a3.jpeg
 

MuensterMann

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So, if you bush, the material is brass; and if you sleeve, the material is steel - correct?
 

R. Croswell

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Jerry, I see from your pictures that you use a 3 jaw chuck.

Is yours precise enough or do you have run out?
Do you use your indicator on the teeth and average the high and lows?
What if the barrel is out of round, like most of them are?
Doesn't the mere pressure of the jaws squeeze or pull it out of round?
I'd be inclined to use a 4 jaw chuck for this but it's a pita to set up,
is the 3 jaw good enough?

M.
You addressed your questions to Jerry and he has responded, so I will comment on the same questions as they pertain to the my setup described in post #9. Yes, there is more than one way to skin this cat but the important thing is that the hole be true with respect to the gear. My 3-jaw chuck has had considerable use and abuse and is probably much less accurate than Jerry's, and yes, a 4-jaw is a bit time consuming to center, but with a dial indicator and patience it is possible to get very near zero runout. That includes canceling out any spindle runout and runout introduced by poorly made barrels or two-piece barrels where the barrel "can" is soldered to the gear. I was suppressed to see Jerry state "If there is runout [part held in 3-jaw chuck], I tap the barrel with a small plastic hammer one way or the other to eliminate it under loupe observation". While the error thus introduced is small, tapping the barrel thus held to bring it to center will result in the bored hole not being perpendicular to the face of the gear. With the barrel held in a 4-jaw chuck I use a dial indicator to check runout at the gear teeth. I also check runout against the face of the gear to ensure that the bored hole will be perpendicular. So is the 3 jaw good enough? - mine isn't, don't know about yours, but I believe an independent 4-jaw has the potential for greater accuracy when used with a dial indicator if one has the patience to get it zeroed in.

RC
 
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Jerry Kieffer

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You addressed your questions to Jerry and he has responded, so I will comment on the same questions as they pertain to the my setup described in post #9. Yes, there is more than one way to skin this cat but the important thing is that the hole be true with respect to the gear. My 3-jaw chuck has had considerable use and abuse and is probably much less accurate than Jerry's, and yes, a 4-jaw is a bit time consuming to center, but with a dial indicator and patience it is possible to get very near zero runout. That includes canceling out any spindle runout and runout introduced by poorly made barrels or two-piece barrels where the barrel "can" is soldered to the gear. I was suppressed to see Jerry state "If there is runout [part held in 3-jaw chuck], I tap the barrel with a small plastic hammer one way or the other to eliminate it under loupe observation". While the error thus introduced is small, tapping the barrel thus held to bring it to center will result in the bored hole not being perpendicular to the face of the gear. With the barrel held in a 4-jaw chuck I use a dial indicator to check runout at the gear teeth. I also check runout against the face of the gear to ensure that the bored hole will be perpendicular. So is the 3 jaw good enough? - mine isn't, don't know about yours, but I believe an independent 4-jaw has the potential for greater accuracy when used with a dial indicator if one has the patience to get it zeroed in.

RC
RC
My personal preference for a general purpose three jaw chuck is about .001" runout but I will not except anything over .002". At that point, I or the mft. will deal with it or it is removed from service. However in this specific case it only plays a small part of the solution.

Your discussion is well beyond what is considered by most clock repair persons, but will serve you extremely well in many respects in the future.

Unfortunately when dealing with spring barrels, real life kicks in. While there are always exceptions, in general, they are far from a accurate machined assemblies per the first two photos.
In the photos measurements are taken 180 degrees apart with a .004" differential that is multiplied the further it extends from a chuck.

Again, you are absolutely correct in that a barrel arbor hole should be centered and 90 degrees to the face of the barrel for arbor hole boring . For this to happen, two things need to happen.
First, the face of the teeth must run true without runout. The face of the teeth can not be be measured with an indicator on the face, but can be measured on the side of the teeth, but only if the surface were machined accurately in relation to the teeth. If you have ever machined on a barrel when replacing teeth, you quickly find out this is rarely the case.
The second thing that must run true is the face of the barrel. The third photo arrows point to the two surfaces being discussed.

By shifting the barrel on the chuck ever so slightly, will generally cause the two surfaces to run true at the same time. Both surfaces are easily and accurately verified by visual comparison (discussed in post #19)under a loupe or optics. For those who have not experienced the accuracy of comparison measurement, it must be experienced to be understood and appreciated.

Jerry Kieffer

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MuensterMann

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For holding barrels is it best to have the 2.5 or 3.1 inch Sherline chuck? Is the Jacob's 1/4 or 3/8 inch better to have for the tailstock, in general, for clock repair?
 

Jim DuBois

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Personally, I would order the larger chuck as well as the 3/8" Jacobs chuck. I have often needed something just a bit larger than what I have.
 

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