Bergeon pivot drilling tool?

Discussion in 'Horological Tools' started by bruce linde, May 1, 2020.

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  1. bruce linde

    bruce linde Technical Admin
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    #1 bruce linde, May 1, 2020
    Last edited by a moderator: May 2, 2020
    bought this off of ebay... billed as a 'Bergeon Pivot Drilling Tool With Lathe Attachment for Watchmaker or Jewelers'

    while i can't really see how one would drill with it, i could see it being used while polishing pivots... with the gear held in a collect or chuck and the pivot to be polished resting in the appropriate slot... at least halfway, allowing one to hold a polisher over it as it turns.

    is it really a drilling tool? if so, how is it used? photos would be appreciated.

    if not... is my idea of trying to fit it to my sherline to help with polishing pivots a reasonable idea? nutty? bad?

    lmk,
    thx,
    b

    p.s. there's nothing on it that says' Bergeon'... ?

    2.jpg 3.jpg 6.JPG 4.jpg 5.jpg 1.jpg
     
  2. Smudgy

    Smudgy Registered User

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    That's not for drilling pivots, but for polishing pivots on a WW lathe. The different sized pivots fit in the grooves and then are burnished with a burnisher to polish them. It can be used on any lathe that has a headstock of the same height as the centerline of the top groove when mounted on a cross slide. If it doesn't say Bergeon on it I doubt it is Bergeon, I don't know anything that is Bregeon that isn't labelled as such, but I could be wrong. It is a useful tool if you have a lathe with a slide. It looks like it is for straight pivots only, and it appears to be made more for clock pivots than for watches.
     
  3. bruce linde

    bruce linde Technical Admin
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    yes! as i had guessed/hoped. i'll need to see if i can make this work on my sherline... and i'm a clock guy so those pivot sizes should work.

    now the question becomes: is there a sherline accessory that lets you mount such items on their cross slide? off to google...
     
  4. brian fisher

    brian fisher Registered User
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    hmm...that is an interesting tool bruce. it looks like it would fit the t slot on a unimat or any lathe with that type of attachment point. the only issue might be the height in regard to the chuck center.
     
  5. bruce linde

    bruce linde Technical Admin
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    Spot on… I’m gonna call Mike at Mike’s tools and see what he has to offer on the subject
     
  6. Jerry Kieffer

    Jerry Kieffer Registered User
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    #6 Jerry Kieffer, May 2, 2020
    Last edited: May 2, 2020

    Bruce
    As Smudgy mentioned, you have a pivot polishing attachment, however you also have several issues.

    (1) I suspect that the numbers are in metric with the smallest being .35mm and the largest 1.4mm. If so, this will fall in the category of a carriage Clock and a larger pocket watch but limited for typical 8 day and other clock movements.

    (2) While it can easily be mounted to A Sherline Carriage slide with minimal modification, This arrangement is actually a poor design in actual use. Each time it is used it must be aligned with the spindle center of rotation in all directions, or pivots can be damaged. A much simpler and more accurate method of mounting is in the tailstock chuck as this will assure accurate alignment without adjustment. The first couple attached photos is an example of one of these devises that I built many yeas ago that was designed for tailstock mounting. The wheel of your devise could be mounted to a similar "L" shaped bracket if tailstock mounting was desired.

    (3) As a slow learner, it took several years to understand that After market and factory accessories can be marketing ploys more so than a useful devise. The devise mentioned above was copied from available devices and looked to be a useful tool. However, in use, it is cumbersome and inefficient when compared to a simple tailstock runner shown in the third photo. Runners are so simple and quick to make that the devise I built was used very little and has not been used since.

    Jerry Kieffer

    fullsizeoutput_59c.jpeg fullsizeoutput_59b.jpeg fullsizeoutput_597.jpeg
     
  7. bruce linde

    bruce linde Technical Admin
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    Jerry - everything you say makes perfect sense to me. I put this item in the not so cheap thrills bucket, but it’s been fun thinking about how one would use it.

    I like the runners, and was even thinking I could drill twice… Once for the correct pivot size and a little bit at the end for the correct arbor size. That would make sure that there wasn’t any excess sideways torque on the pivot... not that that’s a real issue... just thinking out loud.

    The real issue at this point is that I do not yet have a milling machine… Is there a way to make runners easily without one?
     
  8. Uhralt

    Uhralt Registered User
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    I made some of these before I had a mill. I just center drilled a piece of brass rod and filed off half of the brass where I drilled the hole. Done.

    Uhralt
     
  9. bruce linde

    bruce linde Technical Admin
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    you're not helping. you're supposed to say, "bruce... you're now at the point where you really need a milling machine... even if you're just a hobbyist with a shopping problem." :cool:
     
  10. Jerry Kieffer

    Jerry Kieffer Registered User
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    Bruce
    After further examinations of your photos, the scribe marks and other indications are that this devise was almost certainly constructed by an individual. Based on its overall design and appearance. its quite possible it was made for a Sherline, Taig or Unimate Lathe. If the "Tee nut" Fits your slide slot, it may be made for a Sherline.

    Runners are easily machined on a Sherline Lathe.

    (1) Drill desired hole in round stock

    (2) Machine half round with a endmill and hand wheel settings that can be done in a single pass in less than 5 seconds per attached photo. While it can also be done with a file, accuracy is a skill oriented time consuming task.

    Jerry Kieffer

    fullsizeoutput_59d.jpeg
     
  11. bruce linde

    bruce linde Technical Admin
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    where are my enablers when i'm trying to rationalize buying a milling machine?!!? :cool:

    thx for the tip... will give it a shot.

    oh... should i make a set? or whip up as needed? (i guess my collection will grow over time...)
     
  12. bruce linde

    bruce linde Technical Admin
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    jerry - more questions. what is the piece secured to your cross-slide called? is it stock, or did you drill that hole for the brass rod? what are the dimensions of your end mill bit... and how is it secured in place? thx.
     
  13. Jerry Kieffer

    Jerry Kieffer Registered User
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    Bruce
    The 1/4" endmill was held in sherlines MT endmill holding collet on the left in the attached photo.

    Stock for Milling on the Lathe can be clamped in a standard Sherline tool post center of the attached photo. Its limited so thats why you purchase a Mill.

    For Micro work I use Micro boring bars that typically have shanks in sizes 1/8",3/16" and 1/4". This type boring bar normally has a cutting tip centered to the shank. To hold these bars accurately to the center of the spindle, I drill 1/8", 3/16" and 1/4" holes in various standard tool posts (With Lathe spindle) and add locking screws per the post on the right in the photo. Ironically, they have been very useful for holding various other tools for various operations including stock to be machined as in this case.

    Jerry Kieffer

    fullsizeoutput_5a0.jpeg
     
  14. Dushan Grujich

    Dushan Grujich Registered User

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    #14 Dushan Grujich, May 3, 2020
    Last edited: May 3, 2020
    G'Day Bruce!

    Device that You bought is a DIY holder for a Jacot drum, normally used for burnishing pivots, not for polishing them. What You really want is to work harden pivot surface, NOT to get it shiny.

    The proper use of the Jacot drum is with an offset runner, which is also used to hold a centring plate for drilling when in need of replacing damaged or broken off pivot. Jacot drum is made of steel that is glass hardened so that when using pivot file it cannot be damaged, file will just slip over it.

    If You closely observe images below, You can see that the openings are not half of the diameter of the pivot as shown on the "devise" by Jerry Kieffer.

    Jacot_Drum_detail.jpg Jacot_Drum_geometry.jpg Jacot_Drum_in_runner.jpg

    The openings are exposing only 0.05 mm (0.002") of the pivot so that when You burnish the pivot one can only work on the exposed section. This is to prevent making pivot conical or bellied. To illustrate this I have placed a red dot in the slot on the top of the drum so that pivot position can be readily observed.

    Drilling is accomplished using the same runner, mounted in the lathe's tail stock, but instead of Jacot drum one will use one of the centring plates with suitable female centre hole. Images below show the method and the set-up.

    Jacot_Drum_in_runner.jpg Centring_plates.jpg pivot_drilling_acc.jpg pivot_drilling_setup.jpg Drill_bit_runners.jpg

    BTW, there is also another Jacot drum, of the same design, but with slots that are for pivots of smaller diameter.

    Cheers, Dushan
     
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  15. Jerry Kieffer

    Jerry Kieffer Registered User
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    #15 Jerry Kieffer, May 3, 2020
    Last edited: May 3, 2020
    Dushan
    This is an excellent explanation on how the OP`s and your illustrated accessory were designed to accomplish their task.

    In my tool collection, I have a boxed watchmaker lathe set that contains a similar accessory that I used when starting out. However in use, I had some issues with the tool and the tool in post#6 was a modified attempt to solve those issues. You are correct in that the pockets are half round and in addition, the drum is purposely constructed of 12L14 steel and is not hardened unlike my Lathe accessory tool and your tool.

    A properly functioning pivot needs to be straight, round and parallel. In order to create or retain this condition the accessory tool must be perfectly aligned with the spindle. While mine is reasonably aligned not everyone has reported the same experience over the years. My constructed example was drilled in place assuring alignment, so neither has been a issue in this regard. However, in use, having a file/burnisher reference a flat guide spot given the short distances involved was not always assured. It was far less a problem if the pivot is filed down to engage both flat spots, but in most cases I did not want to reduce the pivot diameter by that amount.
    On my constructed example, the file or burnisher is constantly held square by a ball bearing guide per first attached photo. In use, one hand holds the file/burnisher on the guide and the other applies required pressure on the pivot.

    In cases where a steel pivot is harder than a bushing or bearing surface and it is the rotating member, it needs to have a very smooth finished surface. If not, it will simply grind on whatever it makes contact with as it rotates. Burnishing has proven to be an effective and efficient method of applying a smooth finish to a pivot with proper and properly prepared tools.
    In the case of my Watchmaker Lathe accessory tool, no effort was made to grind or polish the pivot pockets. Thus, the hardened unpolished surface at the bottom was scoring the pivot surface while I was trying to apply a smooth surface at the top with a burnisher.
    On my constructed tool, the goal was to provide a ever so slightly softer surface than the pivot thus not disturbing applied finishes. In use, this ended up requiring less effort and time when burnishing with a superior pivot finish in most cases.

    While issues with the lathe accessory tool could be addressed, I have found that the simple brass runner has been more effective and efficient than either the Lathe accessory or my constructed accessory.

    In addition, the second and third photos show a constructed ball bearing arbor support with the idea of doing fine detailed work on unsupported hardened pivots. While I have used it a few times with great success, the verdict is still out.

    The wheel, file and stone were handy items for quick illustration.

    Jerry Kieffer

    fullsizeoutput_5a1.jpeg fullsizeoutput_5a2.jpeg fullsizeoutput_5a3.jpeg
     
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  16. bruce linde

    bruce linde Technical Admin
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    i like the ball bearing guide... but i want one of those ball bearing arbor supports! :cool:
     
  17. bruce linde

    bruce linde Technical Admin
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    meant to ask... is the height adjustable?
     
  18. Dushan Grujich

    Dushan Grujich Registered User

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    Jerry,

    Your set-up, looks nice, but what I see that it can be used to do to a pivot without rigid support is not burnishing, simply because sufficient pressure cannot be applied. Burnishing, if done properly and with quality tools without faults, easily produces pivot with mirror-like and impeccable finish, which is required along with its surface hardness.

    Burnishing is process of plastically deforming pivot made of steel, that is hardened and tempered to blue, by working it with burnisher under substantial pressure over a rigid support, produces a kind of case-hardening, where pivot core remains softer than its surface.

    I am sure that you have seen the Analysis of Pivot Polishing vs Pivot Burnishing done by Robert Whiteman, in 2005 and again in 2008, therefore we do not need to argue the need for burnishing as opposed to polishing.

    Cheers, Dushan
     
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  19. Jerry Kieffer

    Jerry Kieffer Registered User
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    Bruce
    In order for the rest to be useful, it would need to be adjustable. First photo shows the dovetail adjustment. Second photo shows adjustment using a gage pin the same diameter as the arbor.

    Jerry Kieffer

    fullsizeoutput_5a5.jpeg fullsizeoutput_5a6.jpeg
     
  20. Jerry Kieffer

    Jerry Kieffer Registered User
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    #20 Jerry Kieffer, May 3, 2020
    Last edited by a moderator: May 3, 2020
    Dushan

    I assume you are referring to what I described as a arbor support.

    I built this many years ago as an experiment to work on pivots using fine stones to dress to shape and abrasive to polish pivots that were to hard to burnish. It was not designed for burnishing. Most pivots encountered in Horology will require support for burnishing hard or not. While this tool is not used often, it has been very successful at times for various tasks and a life saver a couple of times.

    I do recall the Whiteman report. I do not recall the reason, but I believe he stopped at 1000 grit abrasive on the polishing examples. It has been my experience that a minimum of 4000 grit is required for an aceptable pivot. In addition, how it is applied will determine various outcomes and I do not recall if he specified how it was applied.

    Jerry Kieffer
     
  21. DeweyC

    DeweyC Registered User
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    Dushan is correct. Burnishing is the process of compressing the steel. You actually are increasing the density if you will. This makes the pivot harder and makes the surface smooth. It increases the durability of the pivot and its resistance to abrasion and corrosion.

    A correctly burnished pivot will present a finish that cannot be improved with Diamantine. In fact, polish will degrade the compacted surface of the burnished pivot. If we have a pivot that is oversized after burnishing, we use a degussit stone to cut through the surface to start again.

    A burnished pivot will have a higher Rockwell number than indicated by heat treatment.

    This keeps coming up, typically by those not educated in the theory and practice of watch making and instrument making.

    I agree with Dushan, there is no "fine point" to argue. As in all discussions on this board, there is a difference between making it tick and look pretty and fully restoring function. Some people polish pivots with a pinvise and an emery board.

    As Samelius said in 1944, "It is one thing to repair a watch, and quite another to adjust a watch".

    BTW Dushan, in school I asked the head instructor if anyone ever got the pivot drilling attachment included in the Horia sets to work. He smiled and said he never met such a person. I may have told you this before.
     
  22. karlmansson

    karlmansson Registered User

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    Bruce, you need to get a milling machine :).

    You need to make the runners out of steel that can be hardened. If you use a brass runner you will invariably embed all the small, very hard steel particles that burnishing produces. The burnishing action compresses the steel, yes, but in my experience there will always be some very small "filings" doing this. A shadow on the burnisher and in the runner. The embedding of abrasives is what you want for the polishing method but burnishing is what you want for wear resistance and friction reduction.

    What Jerry says about getting the tool on center and on axis is very important. I have some burnishing drums for my Lorch D-bed lathe and they work well. They are held in the tailstock and have an additional runner with a point that is used to align the burnishing drum with the center axis. Spot drilling a a circle on a slice of round stock with a known center distance will allow you to mount that slab in a tailstock holder where you can make a pointed runner to fit inside the holing tube and bring the drilled spots onto center. Then you can place drills of increasing sizes in the headstock and drill into the steel. Then you need the mill to mill away enough material to be able to use the burnisher on the pivot. Then harden the piece, temper and polish the grooves.

    An alternative is presented in George Daniels "Watchmaking" where he suggests using a V-cutter to on varying depths to create Vs with flat sides to further aid in the burnishing. Never used on like that so can't speak on it's usefulness.

    Hope this helps, and that you finally find you excuse for getting that mill :)

    Regards
    Karl

    Below are the tools in question. The second image shows the pivoting lantern but the principle is the same.

    lorch-watchmakers-lathe-pivot_360_77103896fbc970e632e9ec963b9dcd74.jpg Nr. 10 Pivoting Attachment.jpg
     
  23. Jerry Kieffer

    Jerry Kieffer Registered User
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    #23 Jerry Kieffer, May 4, 2020
    Last edited by a moderator: May 4, 2020
    Karl
    A hardened steel runner will certainly work, but the pocket will need to be ground or you will run into the same issue I did in post #15.

    When I burnish, I use oil inserted in the cavity per the arrow in the attached photo. This provides a continuous source of oil through the process. Under these conditions, I have never experienced any build up of metal particles in the brass runner. However, if I ever do, they are so simple and quick to make I would simply make a new one.

    It should also be noted, that when working on a pivot regardless of how it is done, if the diameter is reduced at all, the pivot hole should be reduced to match the original fit ratio. This is especially important if working on a early fusee watch where depthing should also be checked and corrected if required.

    Jerry Kieffer

    fullsizeoutput_5a8.jpeg
     
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  24. bruce linde

    bruce linde Technical Admin
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    yes... do the pivots first, and then the pivot holes to make sure everything is sized correctly.
     
  25. Dushan Grujich

    Dushan Grujich Registered User

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    Jerry,

    Does it matter if the abrasive grit was 1000 or 100000? The fineness of abrasive does not make the pivot surface any harder or more resilient to wear. Hardness of the pivot surface remains the same as its core.

    The only case when the abrasive grit size would matter, in providing some protection from wear, is if the pivots were iron, not steel, then the only option is polishing, as iron cannot be burnished i.e. hardened by work. Is that not precisely the reason why Hermle plated their pivots, made from soft material, in hope to prevent wear?

    Cheers, Dushan
     
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  26. DeweyC

    DeweyC Registered User
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    Dushan,

    I think you have the point clear that pretty polishing is not the same as burnishing. At this point, it is up readers to decide their goals.

    It is obvious you are not satisfied with making operating models, but seek to restore precision to a watch.

    People will simply have to sort themselves out as to their goals.
     
  27. karlmansson

    karlmansson Registered User

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    Yes, I did bring up the need to polish the grooves in the runner.
     
  28. Jerry Kieffer

    Jerry Kieffer Registered User
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    #28 Jerry Kieffer, May 4, 2020
    Last edited: May 4, 2020
    Dushan
    This subject has been debated to death over the years.

    Forty years ago, I built my first watch moment from bar stock and of course when complete time keeping was not its greatest virtue. As they say, accuracy was perfection twice a day. To make a long story short, over the years I researched the issues and experimented with solutions that often came by accident. These solutions were incorporated in the second movement that has performed up to expectations. At this point I understood what industry and makers went through to perfect a functional movement often with many solutions by accident. Once perfected, it could then be copied and expected to function in the same manner as the original perfected and excepted version. At this point you realize the only person who really knows why something is done the way it is done, was the person who perfected the excepted original version.

    After the experience building the first movement, my goal in servicing a movement, is to return everything in the movement to its original fit and finish state even though no-one will probably know why everything was done exactly the way it was done. Another words, if the original state indicates a surface was burnished, I then burnish it, if and only if required. If it was polished or machined and a replacement must be made, it is then polished or machine per the original. Not to do so would modify the original and you will have a unproven condition. Right or wrong, it has served me well over the years.

    As always I am happy to publicly demonstrate each and every suggestion I may make for all to evaluate and do so on a regular basis.

    Jerry Kieffer
     
  29. DeweyC

    DeweyC Registered User
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    It is good to see that the difference between cosmetic polish and burnishing has been acknowledged for future readers.
     

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