Alternative to Jacot Tool

Discussion in 'Horological Tools' started by ChrisCam, Sep 17, 2019.

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  1. ChrisCam

    ChrisCam Registered User
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    Hi Guys, Having fairly well rereached how to make a balance staff I am curious as to alternative methods of finishing the pivots. The Jacot tool does little apart from rotating the pivot allowing the burnisher to roll the said item into a smooth finish. Could this equally be acheived during machining or some other alternative or is the jacot the only sensible route?
    Chris
     
  2. gmorse

    gmorse Registered User
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    Hi Chris,

    The essential feature of the Jacot tool is the support it provides under the pivot for the required pressure applied by the burnisher. Without this support the pressure would inevitably break the pivot. The burnisher must be applied with sufficient force to make the steel surface 'flow' and produce a harder skin.

    Regards,

    Graham
     
  3. DeweyC

    DeweyC Registered User
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  4. ChrisCam

    ChrisCam Registered User
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    Thanks Graham, Yes I get the point of the Jacot Tool but could you equally hold the end not being burnished in a pin vice and rotate while the supported pivot being burnished is rotated? In any event I note used Jacot tools often come on Ebay often with more or less just the core components whilst other have several tubes etc. What is actually required for platform escapement / clocks?

    Regards
    Chris
     
  5. Uhralt

    Uhralt Registered User
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    You can burnish pivots in a lathe. One way to support the pivot is to drill a hole with the diameter of the pivot in a piece of brass rod, then cut the rod lengthwise in the middle for a bit more than the length of the pivot and remove the upper part. Attach the piece to the tailstock of the lathe. Voila!
    Jerry Kieffer has shown this in a couple of his contributions.
    Uhralt
     
  6. gmorse

    gmorse Registered User
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    Hi Chris,

    Uhralt has described a good, simple way of making a Jacot bed for the lathe. It's important that the arbor is held securely with the pivot parallel to the bed so that a cylinder is formed and not a cone. Just holding a pin vice won't guarantee this and could result in breakage.

    Many Jacot tools for sale are incomplete and/or have damaged beds or lanterns, and it can be hard to tell their condition from the frequently inadequate pictures. The beds should match the diameters of the pivots you're working on, and they're typically sized for watch work, not clock pivots. Most full sets have two runners with a range of beds on one end and a lantern on the other, with a third runner with four longer beds which is meant for the long top pivot on fourth wheels, for the seconds hand.

    Regards,

    Graham
     
  7. ChrisCam

    ChrisCam Registered User
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    Thanks Uhralt and Graham both helpful, I am obviously assessing whether to get the Jacot or not.

    Kind Regards to all

    Chris
     
  8. Jerry Kieffer

    Jerry Kieffer Registered User
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    #8 Jerry Kieffer, Sep 18, 2019
    Last edited: Sep 18, 2019
    Chris
    Procedures and equipment required to produce a staff, will be determined by your decision to cut the staff with a graver or machine the staff.

    If you decide to cut the staff with a graver, the surface finish will be determined by the following factors.

    (1) The quality of the metal used and its ability to be worked.

    (2) The quality of your Graver including sharpening and profile.

    (3) Your ability to control the Graver by your hand.

    Unless your ability to control the Graver is absolute perfection each and every time, you will need to have procedures and or additional equipment to deal with any issues.
    These procedures and tools along with instructions for use can be found in Traditional Horological repair Publications and or formal watchmaker educational courses.


    If you decide to machine your staff results will be determined by the following factors.

    (1) The quality of your metal used and its machining characteristics provided by a reputable supplier

    (2) The quality of a Lathe tool designed for hard steel , its profile and having been factory ground specifically for a fine metal finish.

    (3) A capable Lathe with properly set Lathe tool.

    In the last 150 years or so, commercial balance staffs (even the highest quality) have been machined without any hand procedure assistance. Another words, what you see is what came off of the machine that produced it. However they are generally machined at high speed under flood coolant conditions. In some cases, highest end companies like Vacheron and Patek will in addition, polish the staffs using a vibratory process. Again however, this will not change the structure or geometry of the machined staff.

    When using a manual machine tool Lathe for one off, factory machined pivot finish can be duplicated as follows.

    (1)When the last cut for fitting has been completed, do not touch the depth of cut hand wheel.

    (2) Clean the staff pivot and place a fresh drop of cutting fluid on the pivot and cutting tool

    (3) Very slowly advance the cutting tool to full depth of the pivot at max spindle speed and very slowly back out past the pivot tip.

    (4) Repeat this process about three times without touching the depth of cut handwheel. This should duplicate factory finish. Personally, if for whatever reason, I wish to improve the finish even though my goal is duplicate factory finish, I use a Elgin Sapphire burnisher and polisher. Attached photo.
    This tool is designed for only very light finish work and will not require pivot support, but a runner can be used if desired. I have found that quality cutting fluid has worked best with this tool.

    Unfortunately I have yet to see any Horological or other publication that deals with Micro machining or the use of micro tooling. Metal finishes for machined parts, is covered in a machinist handbook and can be readily observed at industrial machine tool shows.

    Jerry Kieffer

    fullsizeoutput_425.jpeg
     
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  9. ChrisCam

    ChrisCam Registered User
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    Jerry thanks so much for your help on this. Its late here in the UK so I will digest your notes carefully tomorrow.
    Kind Regards
    Chris
     
  10. Old Rivers

    Old Rivers Registered User
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    Unfortunately I have yet to see any Horological or other publication that deals with Micro machining or the use of micro tooling. Metal finishes for machined parts, is covered in a machinist handbook and can be readily observed at industrial machine tool shows.

    Jerry Kieffer



    Jerry, the Horological World anxiously awaits your definitive book on these topics. I'll be first in line to buy a copy!

    Bill
     
  11. DeweyC

    DeweyC Registered User
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    Archie Perkins. Jendritski. Malcolm Wild too name several. They cover all aspects of micromachining.
     
  12. Jerry Kieffer

    Jerry Kieffer Registered User
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    Bill
    Thanks for the kind words.

    However, I am a a very poor writer and prefer to share experiences through demonstrations in the classroom.

    Again however, I have been asked to do a program at the Lone Star regional coming up, maybe I will see you around.

    Jerry Kieffer
     
  13. Jerry Kieffer

    Jerry Kieffer Registered User
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    #13 Jerry Kieffer, Sep 19, 2019
    Last edited: Sep 19, 2019
    Depends on ones definition of Micromachining and Micro tooling.
     
  14. DeweyC

    DeweyC Registered User
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    Indeed. The Swiss and WO Smith (who was hired by NASA to build the micromachining course at the Univ of Illinois in the late 1960s) defined it to include the manufacture of parts for small precision instrumentation. This has been around for decades (gyroscopes, watches, medical components, mechanical computers, etc).

    Even so, the use of machines and slide rests for micromachining watch parts dates back to Waltham and was well described by a number of contemporary authors ). In fact, Waltham taught the Swiss how to set it all up (to their ultimate chagrin).

    Hopefully the sources I provided will help you in your search for literature on horological micromachining.
     
  15. Jerry Kieffer

    Jerry Kieffer Registered User
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    One off Micromachining utilizing common industry practices is something that truly must be experienced to be understood.

    While Micromachining procedures themselves have changed little over the years, in the past, it was most commonly practiced by setting up a specific machine for a specific part often for production.
    This of course is not a practical daily use option for a individual or small shop. In addition, when vintage publications were published, suitable equipment and tooling for micro machining was very limited. What was available (both equipment and tooling) was barely capable of even the most basic procedure by todays standards.

    Fortunately, in todays world, there are a few highly versatile capable and affordable machines and a ton of tooling that had to be made or special ordered in the past. To clarify my statement, I have not seen a publication that would guide a beginning Micro Machinist through these many many options that includes setups and procedures that these options now make possible.

    Jerry Kieffer
     
  16. DeweyC

    DeweyC Registered User
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    Interesting. Precisely what tooling did Archie Perkins or Malcolm Wild have to special order? Personally, I have never special ordered any tooling.

    If you are serious, I suggest you buy Archie Perkins book on the use of the lathe. I cannot think of a thing he does not cover. It is the first book I recommend to every learner who comes to my shop.
     
  17. Jerry Kieffer

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    Actually, Archie Perkins did a pretty good job based on what he had to work with at the time, even though I am not a big fan of time consuming hand procedures.

    However, I personally prefer to machine parts that do not require hand work other than polish and slight fitting when they come of off the machine. This has been possible when utilizing common industry micro machining procedures. Life is to short not to have the exact tool designed for specific applications rather than spend hours grinding what may never perform as required.

    My second bar stock watch movement is mounted in a container that allows students and some others to safely and closely examine it. After students have examined the movement, the attached photo is a small example of commercial lathe tooling that was used in its construction shown for class discussion.
    For size comparison, the Endmill second from the top that was utilized for slotting some screws is .009" or .24 mm. diameter.

    While I have not observed any of the procedures utilizing this type tooling as utilized in the movement construction in any of the Archie Perkins publications, references of unique and efficient procedures/tooling, are always welcomed.

    Jerry Kieffer

    fullsizeoutput_427.jpeg
     
  18. DeweyC

    DeweyC Registered User
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    Precisely how did they rely on "time consuming hand procedures"? That is a very interesting claim of which I am certainly unaware.

    Are you saying they used files and stones to execute all their work?
     
  19. Jerry Kieffer

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    It depends on who you are referring to when you say "They" and no I did not say all work was performed by hand. However, if you read the Archie Perkins publications, much of the work suggested relies on developed hand working skills including the Graver, files, stones and saws as you mentioned

    Manufacturers on the other hand, used and use anywhere from none to very little hand work in the construction process depending on the quality the movement.

    However in the traditional horological repair publications, hand work skills of various degrees is a popular suggestion and can be very useful for those who spend the many years it takes to develop the skills required. But , as mentioned its not my thing.

    This will be my last post on this, since I suspect it no longer has any value to the OP.

    Jerry Kieffer
     
  20. DeweyC

    DeweyC Registered User
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    Oh, the graver again! Jerry you made it clear several times you went to slide rest because you could not master the graver. Fair enough, I am all for people finding a way to do accommodate their abilities. I insisted on building an ADA compliant privy on the Appalachian Trail to serve those who are using ruggedized wheel chairs.

    But, you make claims without the benefit of data. You first claimed there was no literature on micromachining, then you claimed people like Archie had to "special order" tools and equipment. Then you claimed they relied on time consuming hand methods. And I guess I never knew anyone who got into this work because they were racing against a stopwatch.

    As far as I am concerned, it makes no difference how the work is produced as long as the fit and finish are correct. If it can be done with file and no one tell, who cares?

    Let your body of work stand on its own and describe your techniques without trying to say you are better than so and so. The world will sort it all out. Some will prefer the slide rest. Others will prefer the graver. FWIW, there is a reason most WW sliderests are in lightly used conditions. That is because watchmakers found the graver far quicker and convenient.

    I do fail to understand the purpose of comparing yourself to others. It comes across as a lack of confidence or as self-promotion to be quite honest. If the world thinks you belong in the company of Roy Hovey, Ron Decorte, WO Smith, Malcolm Wild, Archie Perkins, Daniels, Jendritski etc, you will get recognized. But saying you are better than them or that you are the only one who ever taught micromachining is really silly.

    As it is, your post #8 in reply to burnishing makes me question whether you even know the difference between polishing and burnishing.
     
  21. Jerry Kieffer

    Jerry Kieffer Registered User
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    Hey Dewey
    I was gone last night, so a little late on this.

    Its interesting that you mention George Daniels.

    Back in 1999 at the International model engineering show in London, I was lucky enough to have been briefly introduced to George Daniels. His only interest in the introduction was that I owned a 1965 Triumph TR-4 that I had restored from the ground up that was a mutual interest of his.

    However, I was so impressed with his confident attitude that right or wrong, I suspect in part, thats where the confident attitude comes from.
    It was certainly contagious.

    Jerry Kieffer
     
  22. DeweyC

    DeweyC Registered User
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    Yes, he had his way. I ate with him, Jonathan Betts and Tony Randall at the Harvard dinner in 1993. In the projects, the best I could do is keep a 1965 Valiant running. Our difference in experience probably explains a lot.
     

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