Lathe Tool Holder

Discussion in 'Horological Tools' started by bbodnyk, Apr 13, 2012.

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  1. bbodnyk

    bbodnyk Registered User
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    Aug 14, 2009
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    I have been practicing using my 8mm ww lathe to cut balance staffs. The lathe has both a t-rest and a cross-slide. I've been using 1/8" HHS blanks grinding them to the correct shape for use in the tool holder on the cross slide or as hand held gravers. In another posting I read that in the NAWCC lathe course the students use brazed carbide tooling such as an AR-4. My question is what kind of tool holders are being used to hold these? I'd like to try using these but my current holder is only large enough to hold the 1/8" sqr bits. I wonder is anyone would be willing to post pictures of their lathe tool holders?

    Thanks
    Bruce
     
  2. The Tick Doc

    The Tick Doc Registered User

    Dec 30, 2007
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    Bruce, thne NAWCC uses Sherline mills and lathes, they use the Sherline quick change tool post which uses a 1/4" tool. Hope this helps.........................TTD
     
  3. wefalck

    wefalck Registered User

    Mar 29, 2011
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    The Sherline toolholders are designed for indexable carbide inserts.

    To my knowledge, there are no 1/8" brazed carbide tools or holders for inserts. The smallest commercially available ones are 6 mm or 1/4". Traditionally watchmaker toolholder seem to have been designed, however, for square 5 mm toolbits.

    To overcome this limitation I made myself a quickchange toolholder along the lines offered by Boley: http://www.maritima-et-mechanika.org/tools/attachments/attachments.html

    wefalck
     
  4. Wefalk, there is more than one kind of Sherline tool post. The standard one will hold any tool with a 1/4" shank, which
    includes any brazed carbide tool bit in the xx-4 series, (i.e. AR-4, BR-4, etc.).

    Bruce, if you want to try using a brazed carbide bit in your watch lathe cross slide, you will have to take a size
    like AR-4 and grind the bottom of the tool shank so it fits in your tool post. The shanks of these tools are regular
    steel and you can grind it on a bench grinder. Make sure to grind the bottom, not the top. If you grind the top,
    the carbide tip will be way above the center of your work.

    Dean
     
  5. Jerry Kieffer

    Jerry Kieffer Registered User
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    May 31, 2005
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    Bruce
    I suspect your question stems from comments I may have made somewhere along the way.

    The NAWCC provides instruction on both traditional watchmakers Lathe and the use of gravers as well as small machine lathes in machine tool mode.

    The watchmakers lathe has been refined for and is most efficient when used with a graver. Small Machine tool lathes are most efficient when used to machine parts in machine mode as in horological manufacturing.

    The NAWCC workshop WS-117 teaches the use of a small machine type Lathe for Micro machining in the machine tool mode. The schools Sherline Lathes are provided for each student for this instruction. In this class, a USA made AR-4 brazed carbide tool is used where a small radius is desired and a E-4 is used where a sharp corner is desired. These tools are designed to be held in a tool post and controlled by carriage and cross slide. However for micro machining such as staffs and smaller items, the cutting tip MUST be set at the center line of the spindle. As such, they are only mounted in the standard tool posts designed for 1/4" Lathe tools. While the school has quick change units available,
    they are not used for micro machining for a couple of reasons.
    First, they are not repeatable enough for micro machining. Second, the large physical size of the units on a small lathe, limits setup options, cutting visibility and machining capabilities.

    A double sided standard tool post allows both tools to be setup (Attached photo) and remain setup for the life of the tool when additional tool posts are purchased. When setting the tool, a very sharp pencil point is generated in the spindle as seen in the attached photo. From this point the cutting tip can be shimmed to the spindle center line point under distortion free magnification. Unless this is achieved, nothing good will happen.

    After setting up the tools, students are required to machine .12 diameter pivots along with oil stops and other staff detail. This is done by handwheel settings along with verbal instruction with about 90% being successful on first try.

    At one time, a regular regional mart vender was selling brazed carbide tools with shanks machined to 1/8" square, but have not seen him lately. It would not be hard for anyone with a mill. However personally, I have not been pleased with cross slide results when compared to similar sized carriage and cross slides of similar quality.

    Jerry Kieffer
     

    Attached Files:

  6. bbodnyk

    bbodnyk Registered User
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    Yes Jerry, I was asking in response to my posting on turning a balance staff.

    I have used carbide type tools on my larger 7x14 Microlux lathe but have found that unless I'm turning something really hard the HHS tools I grind myself work just as well so I tend to prefer using them. Realizing now that your comments were with respect to using a Shireline type lathe, your tool holders are similar to the one I use on my 7x14 although I use a quick change tool post which allows me to switch tools easily.

    I guess my real question would be is anyone using these AR-4 type lathe tools in a 8mm ww lathe? I've attached several pictures of my cross slide/tool post. It appears the distance from the top of the bed to center is 2". The distance from the bed to the top plane on the cross slide is about 1.9". I don't have a "rocker" in my tool post so until I make one I tilt my tool bit as shown to align it to center. I would imagine the answer to my question would be, no, AR-4 type tools aren't used because there is not enough room to make use of them.

    Thanks!
    Bruce
     

    Attached Files:

  7. wefalck

    wefalck Registered User

    Mar 29, 2011
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    The distance between the top of the cross-slide and the lathe centre is 7 mm on most lathes, I believe. So, unless you grind/mill/file down the shank, many brazed carbide tools would be above centre, when being used in the classical lantern-style toolholder.

    wefalck
     
  8. Jerry Kieffer

    Jerry Kieffer Registered User
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    May 31, 2005
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    Bruce
    I have owned a Microlux and currently own a Grizzly 7" mini lathe. While I use brazed carbide, the lack of tool tip control and movement repeatability in these machines makes it far less efficient.

    I use brazed carbide for everything from wood to the toughest metal that can be machined with carbide. If you use the highest quality (Not Chinese) and it is properly setup, it will not make any difference if your metal is hard or soft when machining small staff size pivots. However Brazed Carbide tools were not ground/designed to be used in rocker tool posts. They are designed to be mounted in a tool post that holds them parallel to the slide or lathe bed surface.

    As mentioned I am not a big fan of cross slides for Lathe use. Again however, mounting 1/4" AR-4 series tools on a watchmakers Lathe cross slide is not an issue in many cases. As an example, the attached photo shows a Wolf Jahn slide mounted on a Paulson Lathe. In this case the standard Wolf Jahn rocker was removed from the post allowing a AR-4 tool to be mounted parallel to the slide/bed surface without issue. The height of the tool was adjusted using shim stock. Unfortunately, each time a tool is changed it must be re-setup and proven properly adjusted.
    In this case, the slide shown as with many cross slides, calibration is not provided or is so small and difficult to use, making it is useless. This in turn makes the goal of machining far less practical.

    Jerry Kieffer
     

    Attached Files:

  9. the 3rd dwarve

    the 3rd dwarve Registered User

    Nov 3, 2000
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    Bruce,

    I am not too familiar with watchmaker’s lathes but it looks to me like your lantern style tool post is missing the base and rocker. Do watchmaker’s lathes not use them on their tool posts? Wouldn’t it make set up much easier if you had them?

    Regards,
    J`
     
  10. wefalck

    wefalck Registered User

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    Some lantern toolposts (I have a couple of these) employed a disc of uneven thickness under the tool; by turning it through 360° one could adjust the tool height in a range of about 1 mm. However, it also changes the tool-rake and clearance angles slightly, which may not be desirable for carbide tools with a 0° cutting angle.

    A bit off topic, but just to say: The absence of micrometer dials is a feature of earlier watchmakers lathes. Unfortunately Wolf, Jahn & Co. and Boley made their dials rather small and from steel, making them difficult to read. On Lorch, Schmidt & Co. lathes, they were made from brass and a tad bigger. Later LS&Co. and Boley had brass drums of about 20 mm diameter.

    wefalck
     
  11. bbodnyk

    bbodnyk Registered User
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    To All!

    I do believe that watch lathe tool posts probably have rockers to adjust the angle of the tool. My lathe was missing it and making one is on my "to do" list next time I have some time to fire up my Microlux. I've pretty much given up on the idea of using brazed carbide on my watch lathe, it doesn't make too much sense. I'm sure my cross slide unit does not have the accuracy of the Shireline ones so it makes little sense to use it except I'm thinking to hog out material until I get close to the size I'm aiming for and then use hand held gravers to complete. Of course it depends on what I'm turning. Larger parts I can probably do entirely using the cross slide. Balance staff turning will require hand work.

    While a Shireline lathe would be nice I've got my mind set on some sort of milling machine as my next major tool purchase. Then I can start making jigs and fixtures and all sorts of tools!

    Bruce
     
  12. Dushan Grujich

    Dushan Grujich Registered User

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    Good Day!

    I have ground broken tungsten carbide centre drill bits that are 3.0 mm in diameter to required shape. To be able to hold them in the tool post I have made a holder from a short length of a 3/16" square section mild steel bar which I drilled a hole at one end. Used a single grub screw to hold the bit in place, which BTW proved to be quite sufficient.

    Although I am using a Tripan 011 QC tool holder, the same tungsten carbide tool with its holder can be used in a simple tool post. It is small enough to fit any WW tool post and it does the work it is intended to and of course it is cheap enough to make no need to buy it.

    Cheers

    Dushan


    [​IMG] [​IMG]
     
  13. bbodnyk

    bbodnyk Registered User
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    Dushan,

    What are you using to grind & hone your carbide drill bits? After reading your post I realized I can buy 1/8" sqr carbide tool blanks and hold them the same way I'm holding my HHS ones. Then the issue is grinding them to the shape I need and honing them. Maybe I can use carbide tools for my watch lathe.

    Bruce
     
  14. Dushan Grujich

    Dushan Grujich Registered User

    Jun 20, 2003
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    I am using a 4" diamond wheel in Alexander 2CG tool and cutter grinder.

    Exactly! There should be no problem with that.

    It should not be a problem either. You can do the grinding using ordinary bench grinder with a green wheel.

    The images in my previous post are of a Swiss, extremely well made Favorite II, 8mm watchmakers lathe. Quite often when turning with cross slide I use tungsten carbide cutters. However, when turning balance staffs I am using a fold over T-rest and 1/16" tungsten carbide graver. Of course, the steel that I use for staffs is hardened and tempered thus a need for tungsten carbide graver.

    Cheers

    Dushan
     
  15. dshumans

    dshumans Registered User
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    Sep 17, 2009
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    Be CAREFUL of grinding tungsten carbide dry. The powdered residue floating in the air is very harmful to breathe due to the cobalt in the compound. All professional tungsten carbide grinding is done using breathing protection and water or oil on the bit and wheel so there is no powdered airborne residue, but fine droplets containing metals can also become airborne, so wear faace and nose protection. Also be careful of paper towels, sponges or rags used to clean up after wet grinding because after they dry, the powder on them can become airborne. It looks like nice clean metal... it isn't. The problem is that these metals damage lung tissue, which becomes scarred and damage continues with the particles in your lungs. Scar tissue can't transfer oxygen, so as it builds up.... well you get the picture. Here is the US Govt. required MSDS (Material Safety Data Sheet) for tungsten carbide.

    http://www.casmetcarbide.com/images/Casmet_MSDS-WC.pdf

    Doug
     
  16. Dr. Jon

    Dr. Jon Registered User
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    Dec 14, 2001
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    Steve Lindsy sells a nice carbide tool designed for engraving but which I have used fir both slide rest and hann held cutting. These are almost as good a Barkus carbide which is the legendary gold standard. They are 3.32 square and very well finished. They are solid carbide.
     
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