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rare earth magnets for cavity control covers

Discussion in 'Luthier's Corner' started by jimmy ray, Jan 28, 2006.


  1. pretty much like the title reads, i'm in the post-planning, pre-cut stages of a walnut bass, and i'm wondering if using rare earth magnets to hold the control cavity cover in place would be suitable, for easy access and a clean look, but if they would have a negative effect towards the pickups and pots? also, would the magnets be acceptable for a truss rod cover on the headstock?
     
  2. fookgub

    fookgub

    Jun 5, 2005
    Houston, TX
    They would work fine. The electronics don't care about magnets, and they'll be too far away to affect the pickups significantly. If you haven't already, take a look at the way Dingwall does his covers... very elegant. I think they would be fine for the truss rod cover, too, but may be tricky to install. Also, you want to make sure the fit is good so it doesn't vibrate.
     
  3. A9X

    A9X

    Dec 27, 2003
    Sinny, Oztraya
    Get a few magnets and experiment. They're usually cheap.
    For the trussrod cover, if your rod has a bullet end, why not try the magnet attached to the cover, so the rod is what it's being attracted to? May need to be spaced etc, but only one meagnet needed.
     
  4. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    Walnut bass, magnet for the cavity cover - Hambone did just that, too :smug:
    There were a lot of pictures of it... somewhere....

    As for the trussrod-cover: since you can't make a sunk-in design there, I'm afraid it would resonate while playing...
     
  5. Cerb

    Cerb

    Sep 27, 2004
    Indiana
    Actually, I will be experimenting with this for a truss rod cover at the body end on my current (uh huh. You know the one) project. The truss rod cover is simply going to be an extension of the fingerboard. I have a few very strong type N45 magnets that I can simply install with a forstner bit and some superglue. I see very little chance of resonation, considering the strength of these magnets.
     
  6. LajoieT

    LajoieT I won't let your shadow be my shade...

    Oct 7, 2003
    Western Massachusetts
    Anyone have a decent source for these things?
     
  7. Hello all,
    I use magets (5mm deep x 8mm wide) on my control covers and truss rod covers and they work well, I drill the manets in to the body and drill in a 1mm round peice of steel in to the cavity cover, two magnets are too strong I find (and too deep for the cover)
     
  8. ok I can't find out how to edit so I'll post again, Imm thick steel I ment and 8mm round, and you get no resonation at all from the truss rod cover
     
  9. LajoieT

    LajoieT I won't let your shadow be my shade...

    Oct 7, 2003
    Western Massachusetts
    Should be right down in the lower right corner of your post there are usually 2 buttons for other peoples posts ("Quote" and "Quick Reply" which looks like a page with a feather quill pen), and 3 for your own posts ("Edit" and the same previous 2). Click on the "Edit" button and it should be clear.
     
  10. bang on, just what the doctor ordered.almost what I use.
    oh I see it noe edit button, doh!
     
  11. thanks for the replies guys, it looks like tommorow i'll be heading around town looking for a few of them. for the truss rod cover, if they rattle (i'm 50/50 on the idea they will or not) but perhaps routing out the space under the truss rod cover by like a 1/16'' maybe?
     
  12. Cerb

    Cerb

    Sep 27, 2004
    Indiana
  13. LajoieT

    LajoieT I won't let your shadow be my shade...

    Oct 7, 2003
    Western Massachusetts
    Excellent!!!!



    {Orders 100 Supermagnet #4's and 1 set of plans for the Doomsday Ray}
     
  14. River Gambler

    River Gambler

    Feb 10, 2005
    Parts Express.com part# 329-042. 3/8d x 3/16h. Tom
     
  15. Suburban

    Suburban

    Jan 15, 2001
    lower mid Sweden
    Control cavity cover will be OK, as will a truss cover at the head.
    Inserting a strong magent by teh strings, as with the truss cover on the body, will impact the vibration of the center strings. You will have uneven response.
     
  16. yeah forgot to mention that, my truss rod cover are headstock ones, don't stick a whopping great magnet under your strings :eek:
     
  17. Cerb

    Cerb

    Sep 27, 2004
    Indiana
    I had certainly considered that. But, I'm also considering that the magnets are only going to be about 1/4" diameter, and also under about 3/8" of wood. I don't see it becoming a problem. One way to find out, though, right?
     
  18. Trevorus

    Trevorus

    Oct 18, 2002
    Urbana, IL
    Oh, my.... Those super magnets sound dangerous. I almost want one, but it sounds like it would be too dangerous to even look at, let alone touch!
     
  19. I'm doing the same! althought a little different. My magnets are superglued to the cavity cover. On the body I drilled some flat screws that go about the thickness of the magnet deeper than the surface. That way I don't have to worry too much about the depth of the whole, since I can just adjust the screw to adapt to the magnet.