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Can you Re-orient Alnico magnets with Neos?

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  • Can you Re-orient Alnico magnets with Neos?

    So since the wider bar magnets are looking like a no go and I don't want to use a steel blade I decided to do some design changes.
    I went with a .5 x .75 x .187 (standard bar magnet cut down) per pole instead of the bar magnet. Now since the stock magnets won't be oriented correctly once cut, can I use Neodymium magnets to orient them the way I need them? Here's a rendering of what I'm working on.
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  • #2
    The magnet will probably only charge across the width of the original width.
    If the bar was a .5 x .125 x 2.5, before cutting, I think it will only charge across the edges of the .5".
    You can try it to see.
    I think these properties are locked in with heat.
    Anyone else got any info on that.
    T
    "If Hitler invaded Hell, I would make at least a favourable reference of the Devil in the House of Commons." Winston Churchill
    Terry

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    • #3
      1) who cut them?
      Alnico is one of the hardest steels, harder than tool steel for sure, so normaly it's cast in its rough shape and only ends are ground flat with diamond wheels.

      2) Alnico comes in 2 varieties: isotropic and anisotropic.
      Isotropic can be magnetized in any direction, but is weaker.
      Anisotropic (what's used for speakers) is optimized in one direction (along the axis) so others, specially perpendicular to it, are much weaker.
      I guess the bars you pickup guys use are anisotropic, and have a preferred orientation.
      Optimization is made melting the magnet and magnetizing it while liquid, so all microscopic magnets point in the same direction, and stay there after cooling.
      Obviously you can't change that orientation unless you repeat the process, impossible at home.

      Yes, it will charge *somewhat* (although it will be very hard to "erase" the previous magnetization) , but results will be poor.
      Juan Manuel Fahey

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      • #4
        Well drat, looks like I'll have to go with option 2, the ones in the back with standard j type magnet layout. The rectangle ones looked so slick too. I'll get both of the traditional J bridge tones I guess.
        Last edited by Will_White; 06-09-2015, 04:14 PM.

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        • #5
          Originally posted by J M Fahey View Post
          1) who cut them?
          Alnico is one of the hardest steels, harder than tool steel for sure, so normaly it's cast in its rough shape and only ends are ground flat with diamond wheels.

          2) Alnico comes in 2 varieties: isotropic and anisotropic.
          Isotropic can be magnetized in any direction, but is weaker.
          Anisotropic (what's used for speakers) is optimized in one direction (along the axis) so others, specially perpendicular to it, are much weaker.
          I guess the bars you pickup guys use are anisotropic, and have a preferred orientation.
          Optimization is made melting the magnet and magnetizing it while liquid, so all microscopic magnets point in the same direction, and stay there after cooling.
          Obviously you can't change that orientation unless you repeat the process, impossible at home.

          Yes, it will charge *somewhat* (although it will be very hard to "erase" the previous magnetization) , but results will be poor.
          juan is correct, and I must also add that the geometric shape of the magnet is also important, even if the magnet was unoriented, it would not charge very well if you tried get the poles in the large flat faces, I recall something about this, and optimal ratios for this, but I just don't have the info handy

          possibly the easiest solution is to use some flat bar with tiny neos underneath

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          • #6
            I wanted to charged through the .75 of a .5 x .75 x .187

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