interchangeable fretboards

Discussion in 'Luthier's Corner' started by uethanian, Feb 7, 2009.


  1. uethanian

    uethanian

    Mar 11, 2007
    i could swear i made a thread about this a long time ago...but nothing in the search. but anyways this time its different because i'm actually working on it and not just speaking hypothetically

    so for a while i've wanted an instrument that could change fretting templates to whatever i wanted, rather than being fixed to one scale. i've had the chance to play on a guitar that actually had this ability - the fingerboards could be attached/detached by use of magnets. works great, but the official kit is too expensive (the kit i'm referring to is a descendent of the Tom Stone 'Novatone' fretted/fretless bass deal, if anyones familiar with it). that particular setup has a sheet of ferrous sheet metal glued to the neck, and under each plastic fingerboard there's a sheet of magnetic rubber.

    i just received today an order of magnetic sheet rubber, as well as a sheet of 'receptacle' sheeting, which is non-magnetic but ferrous rubber. as it turns out, even the weakest sheet attracts very well...its easy to peel off, but very hard to slide laterally, which was what i was looking for. also the back of the magnetic sheet doesn't seem to attract bass/guitar strings at all, which is good because i was worried about string pull. so my plan is, glue a piece of the receptacle sheeting to the neck, and each fingerboard would be made out of the magnetic sheeting glued to some rigid playing surface...

    ...i should also mention i have a supply of special fretwire, that's essentially tang-less.the bottoms are flat and are meant to be glued to fingerboards. its from the official kit i mentioned above...

    so the main issue i'm facing right now is what to use as the playing surface...i'm looking to keep the whole setup to around .10 inch thick (also a measurement of the official kit), because that will be the amount of wood i'll need to take off the fingerboard. i was hoping to use some kind of plastic...i can either order 1/16" plexiglass, or .020/.030" styrene sheets. i have no idea how this stuff handles, because i've never seen plastic sold that thin. it needs to be flexible, so that the 'fingerboard' can match the bow of the neck and achieve a solid connection. but not too flexible, because i don't want frets popping off if it bends too much. anyone work with this stuff before?

    but in the meantime, i should start working on the neck. i need to get it completely flat, and take that .10 inch off. so how to do this? should i plane it, or should i use some elbow grease and sand it? and if planing, how would i go about that (not at all familiar with planing)?

    i guess this is a bit long but there's a lot to say...and reading back over it looks confusing. anyone have advice?
     
  2. uethanian

    uethanian

    Mar 11, 2007
    haha hey yea that one.

    thats a good suggestion in that thread, with putting blocks on either side of the neck to guide sanding. with planing, i just don't know...

    i only want to take 1/10"...surely the truss rod is low enough to not be affected?
     
  3. pilotjones

    pilotjones

    Nov 8, 2001
    US-NY-NYC
    - Where did you get the tang-less fret wire?

    - I see a need for experimenting with different types and sizes of plastic substrates, and different adhesives to find what will give you something that is stiff enough, yet flexible enough, and won't lose its frets.

    - this will be an interesting experiment in materials vs. tone, since on the one hand there are people who think that fretboard choice and fret type are essental to tone, and on the other hand you are putting a layer of vibration-deadening rubber between the fretboard and neck!
     
  4. dblbass

    dblbass Commercial User

    Mar 24, 2007
    Beacon, NY
    Owner of MBJ guitars, Maker of fine sawdust for Carl Thompson Guitars
    this seems like kinda a bad idea to me. i think removing the fretboard and replacing it with plastic might cause some weird twisting and bowing in the neck. and then if you switch them regularly...i dont know...i just see problems:meh:
     
  5. Taylor Livingston

    Taylor Livingston Supporting Member Commercial User

    Dec 25, 2002
    Oregon, US
    Owner, Iron Ether Electronics
    1/16" plexi will be extremely flexible. I imagine it will be hard to get it to lay perfectly flat without any peaks or valleys, which would make for buzzes or fretting out at the wrong spot. It will also be hell trying to glue metal to plexi cleanly.

    But I'm looking forward toseeing what you come up with.
     
  6. scottyd

    scottyd Commercial User

    Nov 17, 2006
    Waco Tx
    Builder/owner Redeemer Basses
    It sounds good for going from fretted to fretless but If your wanting to change scale length, you have to have the bridge move as well.
     
  7. Taylor Livingston

    Taylor Livingston Supporting Member Commercial User

    Dec 25, 2002
    Oregon, US
    Owner, Iron Ether Electronics
    I believe his aim is to change into different tuning systems, i.e. swapping between 12 tone equal, various just intonations, etc.
     
  8. uethanian

    uethanian

    Mar 11, 2007
    i got the wire from the guy who sells the kits. can't say much about it, other than its normal height, normal nickel/silver composition. this is the best picture i can get of it.

    Photo16-1.jpg

    it may seem like the bottom edge would create an uncomfortable bump, but put down on a flat surface its really so thin that it's not noticeable.

    here's a sample of the rubber:

    Photo19-1.jpg

    the part glued to the board is the receptive material, and the part on top is the magnet. the first is .025" and the second is .020"

    while it's true that the rubber will rob some vibration, i've played an acoustic guitar with this and it still sounded ok. the rubber is thin enough that it still feels hard to the touch against wood.

    the plastic is the next problem, since i have to order all of this stuff without knowing what its properties are. i could go with aluminum sheeting, but i'd rather not as it would be more difficult to cut and would probably dent or bend.
     
  9. uethanian

    uethanian

    Mar 11, 2007
    i couldn't really say. the whole bottom of the 'fingerboards' will be covered with the magnetic sheet, so that should force the them to lay flat. however, getting a solid connection really depends on how flat i can get the neck.

    because the fretwire has a wide base, i don't think glue will be leaking out the sides too much. although i'm much more worried about the frets just staying on, rather than how they look.

    but i'm not actually removing the fretboard, just taking a little off the top. the neck shouldn't lose any significant strength after the conversion. the 'fingerboards' i'm talking about are more like thin sheets, not something that would affect the neck by taking them on and off.

    thats right, i'm doing this specifically for justly-tuned greek tetrachordal scales
     
  10. Taylor Livingston

    Taylor Livingston Supporting Member Commercial User

    Dec 25, 2002
    Oregon, US
    Owner, Iron Ether Electronics
    Could you post a close-up shot showing how you're planning to mount the wire to the substrate? I'm a little confused.

    BTW, if you get this working, you've got a customer (assuming you want one). :)
     
  11. uethanian

    uethanian

    Mar 11, 2007
    here's a quick sketch of the layout. the fret would just be superglued or epoxied on to the plastic

    Photo22-2-1.jpg
     
  12. Taylor Livingston

    Taylor Livingston Supporting Member Commercial User

    Dec 25, 2002
    Oregon, US
    Owner, Iron Ether Electronics
    So you're using the part that normally would be in the slot as the contact point with the string?

    Are you going to have some sort of registration pins or some layout of positive and negative magnets to keep the fretboard lined up where it should be?
     
  13. madmachinist

    madmachinist

    Dec 28, 2008
    i recall the "novatone switchboards" from the early '90s .
    never seen /used them . kind of a novelty at the time..great
    idea ... didn't catch on (remember the 2tek bridge ?) .
     
  14. uethanian

    uethanian

    Mar 11, 2007
    no, its a bit hard to explain the frets, but the wire is is made so that the crowns are normally shaped, but instead of a tang on the other side there's a flat surface. so for the most part they feel and function the same as regular frets.

    and no, there's no guides for the fretboards. the entire bottom of the fingerboards is magnetic, so the entire area attracts to the neck. and once its attached, its not going anywhere...it's not a strong magnetic force, but with this amount of contact area, it takes almost all my strength to slide the things laterally (although they still detach easily when pulled up). perhaps the picture is a bit misleading...the 'magnetic rubber' and 'receptacle rubber' are not smaller pieces, they are sheets that cover all the available surface.
     
  15. Taylor Livingston

    Taylor Livingston Supporting Member Commercial User

    Dec 25, 2002
    Oregon, US
    Owner, Iron Ether Electronics
    Yes, but in order for tuning to be accurate, the fretboard will need to be seated and aligned perfectly, and you need some kind of mechanical assurance that this is the case. You can't just eyeball it and slap it on and expect perfectly tuned intervals. Some simple pins with receptacle holes would do the job, I imagine.
     
  16. uethanian

    uethanian

    Mar 11, 2007
    you'd just butt the end of each fretboard against the nut, which would both square the fretboard and ensure that the fret distances were accurate. i guess i didn't mention that i'm leaving the original nut in...that way there's no need to detune or take strings off between fretboard changes. and of course each fretboard would be cut to the shape of the neck fingerboard, so it would be easy to see/feel if it was not aligned properly.
     
  17. pilotjones

    pilotjones

    Nov 8, 2001
    US-NY-NYC
    Something else: Magnetic sheets like that are typically laid out with "stripes" of north and south poles on one face, and effectively no magnetic poles on the other.

    If this is the case with yours, then by using these sheets on both sides without knowing about this can cause a further problem with installing and alignment in addition to those already mentioned. One sheet will locate itself with respect to the other, with a N stripe of one against a S stripe of the other, regardless of where you want it to go. Even if you did have registration pins, the magnets would fight them unless you happened to hit it just right.

    To test this: put the sheets together, staggered by maybe an inch. Make a pencil mark line at the edge of the top one, onto the bottom one. Separate them, and put them back together, attempting to put them just a hair off. Mark again. Do this a few times, and see if you develop a pattern of lines 1/8 - 1/4 inch apart, which would correspond to to your magnetization field lines spacing.

    This can accommodated, and maybe be used to your advantage, though. If you bring the sheets together to their "preferred" relationship, and then cut them both together at a line that will butt up against the nut, then you should be good.

    Another alternative is to use magnetic sheet on one side and thin steel on the other, avoiding the problem entirely.
     
  18. just get a fretless, no problems with needing to change fretboards because of frets...
     
  19. Darkstrike

    Darkstrike Return Of The King!

    Sep 14, 2007
    Hmmmm, could you put the magnetic rubber between the neck and fretboard, and use an ebanol fretboard? Should be stiff enough, yer still somewhat flexible for the neck curve, and is a often enough used fretboard material.
     
  20. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Jun 19, 2021

Share This Page