Demagnetizing lathe tools........

Discussion in 'Woodturning Discussion Forum' started by odie, May 1, 2017.

  1. odie

    odie

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    I was demagnetizing some lathe tools the other day, and there may be an advantage to demagnetizing scrapers where a raised bur is the objective. My usual method of eliminating magnetized particles clinging to the tool after grinding, is to whack it on a piece of wood. It's a good idea to do this, because metal particles introduced into your turning could cause discoloration with time. Anyway, it seems like the larger particles are eliminated with the whack, but smaller particles (almost like dust) will remain. I can't tell for sure, but it seems like the raising the bur is a bit smoother when the metal dust is not there, resulting in just a little bit of increased fineness of the edge quality. The "dust" is microscopic, so it could be my imagination when it seems the resulting bur is a bit finer when the surface is completely clean......and, this is where demagnetizing comes into play.

    The demagnetizer works like it should, and small amounts of magnetism are completely eliminated. IMG_2782.JPG IMG_2784.JPG
    ko
     
    Last edited: Sep 6, 2017
  2. Gerald Lawrence

    Gerald Lawrence

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    Odie your theory is interesting however I cannot see ultramicroscopic metal particles sticking to the turning thru turning and sanding and then cleaning to remove dust particles before finishing.
     
  3. odie

    odie

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    Note: There are plenty of these magnetic tape erasers available on eBay for cheap:
    http://www.ebay.com/sch/i.html?_fro...+tape.TRS0&_nkw=magnetic+tape+eraser&_sacat=0

    The best way to use it, is to hover about 1" over the cutting edge of the lathe tool. Press on button. Make circular motion while slowly raising the unit to about a couple feet above the lathe tool.

    Of course, it also works on screwdrivers, or anything else you'd want to eliminate magnetism.

    (I suppose I ought to give credit to Rob Wallace, whom many of you know, for first giving me knowledge of the magnetic tape eraser.......thanks Rob!)
     
  4. Raul McCai

    Raul McCai

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    I hate magnetized tools it dives me nuts when tools pick up metal dross and shavings. I looked and looked for a good demagnetizer and decided to just make one.
    I got a big spool of fine magnet wire, and for a bobbin I cut out two wood disks with a center axle and using my lathe, wound the magnet wire on the bobbin the gap between the discs about 1/4" then when it was filled up I put a light bulb on the circuit connected the two ends to a switch on a wood box I made for this and put a power cord on it.
    The bulb is only necessary because it gives the circuit some work to do other than just heat up and buzz.
     
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  5. john lucas

    john lucas

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    I don't mind magnetized tools. Doesn't bother me at all. That being said I've had a magnetizer/demagnetizer since I took the camera repair course back around 1983. It was really handy having some screwdrivers magnetized and at other times not magnetized to hold those tiny screws. I still have it and pull it out occasionally to either magnetize something or demagnetize something.
     
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  6. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Odie, here's a bit of trivia: did you know that you can very slightly magnetize a steel bar by orienting it in a north-south direction and pounding the fool out of it with a big steel hammer? If you repeat the above with the steel bar in various random orientations it will partially, if not fully, demagnetize the bar.

    Another way to demagnetize iron or steel is to heat it to the Curie temperature of 1418 degrees Fahrenheit ... probably not a practical solution for turning tools. :D

    I remember when you first got the bulk tape eraser. They have become somewhat of a relic since magnetic media isn't being used much any longer, but you can still find the bulk erasers on eBay. They were used to demagnetize reel to reel tapes, cassette tapes, eight track tapes, VHS tapes, floppy disks, and shadow masks on color CRTs.
     
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  7. Bill Boehme

    Bill Boehme Administrator Staff Member

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    I also don't like magnetized tools. I have a screwdriver that always has a wad of filings stuck to the end and a bench vise that gets filings between the jaws. It's my fault that the vise is magnetized because I stuck some super magnets to it.

    The light bulb limits the current and keeps the coil from burning up. If you don't want a strong electromagnet you can use a low wattage bulb or use a high wattage bulb for a strong electromagnet. Needless to say, the bulb needs to be the old fashioned tungsten type and nor a CFLor LED.
     
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  8. olaf Vogel

    olaf Vogel

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    I just stick a couple of rare earth magnets inside the dust shields of the grinder.

    The main purpose is to keep the stuff out of the air - and me from breathing it.
    However it should also keep most metal dust off your tools.

    A few months ago I hooked up the dust vac to those shields. So that should further help the issue.
     
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  9. Bernie Hrytzak

    Bernie Hrytzak

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    Olaf, I did something similiar, my small vacuum failed after a few months due to grinder dust passing thru the brushes or bearings. It was very effective while it lasted though. Perhaps the design of that small vacuum.
     
  10. John Torchick

    John Torchick

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    I worked in a model shop of two appliance manufacturers. Screwdrivers were not magnetized so I used a piece of masking tape wrapped around the screw and the shank of the screwdriver. Start the screw and get it almost into the metal, pull the screwdriver, remover the tape from the screwdriver, run the screw in snug. I find that masking tape is great for a lot of things around the shop.
    Thanks for the info on this thread.
     
  11. Mike Johnson

    Mike Johnson

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    When you drop a metal tool in a pile of wood shavings having a magnetized tool simplifies
    the process of locating your lost item. I have a stack of rare earth magnets that I usually use
    to fish through the pile of shavings until it finds my lost metal tool. Aluminum, Brass, or Stainless Steel
    is another story. :-(
     
  12. Raul McCai

    Raul McCai

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    I've seen clumped iron filings start a fire.. A little spark gets it going. A month or so back I was sharpening a set of mower blades and I had just such a little fire. It smoldered and smoldered til finally it had my attention. Then I took a garden hose to it. Walked the hose into the shop and let 'r rip. That's the nature of those fires. They take a very long time to develop into something. The dust collector on the grinder might end up being an issue too; do you have a proper spark arrestor on it?
     
  13. robo hippy

    robo hippy

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    Hmm, I have found fuzzy tools if I set them down by my grinder. As far as being magnetized, it is very minimal. I do tend to tap the tool on metal rather than wood, and this seems to remove just about all of the metal dust. If I am in finish cut mode with my green wood, I will wipe the tool off with wet shavings or a rag to get all of the particles off. Those little black spots and finger prints all over a finish turned green piece just do not look good. Not sure that you can ever get it all off though.

    As far as the burr goes, I am starting to favor the burnished burr, which I think is what you are referring to Odie. I hand burnish, and considering that the burnishing rod only touches a very tiny bit of the edge, no idea how that will effect any changes in how good the burr is. It takes very little pressure to raise a burr.... Now you have me wondering if putting a little lapping fluid on the burnishing rod would do any thing...

    robo hippy
     
  14. Leo Van Der Loo

    Leo Van Der Loo

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    Operators in the automotive assembly plants that would drive screws into the car body that had drill bit like ends on the screws, had the problem of metal sticking to their driver tips.

    Even when using SS screws, with the drill slivers from the cars steel, to keep the driver tips seated into the screws they had to constantly poke the tips into a tar like substance where the slivers would stick into, or the tips would strip out of the screw and then damage the car, a mayor problem.

    Anyway if your tools pick up metal slivers, some soft tar ball could be used to clean all of the metal dust off of it.
     
  15. odie

    odie

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    Yep, "raised bur" and "burnished burr" are synonymous for the same thing, Robo...... To my thinking, when the very tip of the edge is drawn across the carbide (or burnishing rod, in your case), the act of doing this actually further increases the sharpness.......as well as bending it sideways, and upwards. I think this is because the one side of the edge isn't honed, but is rubbed smoother than any hone can do it. When I first started using the Veritas, I applied way too much pressure, and have come to realize a firm, but moderate amount of pressure is all that's needed to raise the bur to a point where it's useful. Raising it more does not increase it's effectiveness. Raising it more also makes it more difficult to start over and raise a new bur, once the old one is dull. If you should experiment with your idea, and find lapping fluid is beneficial......let us know your findings, Robo. :)

    -----odie-----
     
    Last edited: Sep 6, 2017
  16. stu senator

    stu senator

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    Use the stickey side of duct tape as your tar ball.
    Stu
     

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