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microtonal fret job?

Discussion in 'Luthier's Corner' started by uethanian, Jul 29, 2007.


  1. uethanian

    uethanian

    Mar 11, 2007
    its likely no one here has experience with this, but TB is always a good place to go for luthierie questions.

    im planning on fretting a guitar (and later a bass) to a certain microtonal scale, and i need a way to slot fretlets, like in this picture:

    http://www.organicdesign.org/peterson/guitars/ji_mugshot_big.jpg

    im not interested in the bent frets (and i have absolutely no clue how they do that), but i gotta have the fretlets. my first option is to cut all the way across the board with a slotting saw, put in the fretlet, and then put filler in the unused places. but that sounds pretty messy.

    so is there any tool that can cut these kind of slots? a hand tool would be prefered, i dont have much of a budget for this. as for power tools, i have a dremel and a plunge router.
     
  2. SDB Guitars

    SDB Guitars Commercial User

    Jul 2, 2007
    Coeur d'Alene, ID
    Shawn Ball - Owner, SDB Guitars
    The easiest way would be to cut the slots clear across, then fill them with a matching veneer of some kind. Easiest might be to use ebony or something for your fretboard material, and fill with ebony dust, or black CA glue (Stew Mac carries it).

    As for the picture you showed, I'm fairly certain that they epoxied the frets on as opposed to setting them into standard slots. They also rounded the ends of all the frets to be semi-hemispherical, which feels right sexy, but is kind-of a pain to do, as you have to cut all the frets to exact length and round the ends prior to setting them into the neck... you can't file them that way after gluing them down, at least not the ones that stop in the middle of the board.

    So, yeah... recommend ebony board, slotting all the way across and then back-filling the remaining slots.
     
  3. 202dy

    202dy Supporting Member

    Sep 26, 2006
    Here are some guesses as to how to handle this job.

    It might be possible to cut the slots. The hand tool would be a variation on a fret slot cleaning saw. The Eberle Blitz Saw has removable blades that are 20 TPI. There is a .5 mm blade (~.020"). Stew-Mac used to carry this tool. The blade would be modified in the shop to be short enough to fit between the binding at the first fret. It is used to clean out the slot prior to refretting. The blade length can be cut to a bit smaller than the length of the fret and should still be stiff enough to cut the slot. The fret would have to have the tang nipped on both sides to cover the slot for a clean look.

    Another thought is that a couple of .022-.035" holes could be bored near the fret ends and the tang would be eliminated in such a way as to have a couple of "spikes" on the bottom. Experiment on scrap to figure out the best size hole. The fret would need to be set in place with epoxy.

    As far as bending the frets goes, fret wire is pretty cheap in the scheme of things. Buy an extra couple of feet and use a vise and a pair of fret bending pliers to get them where they need to be.

    N.B. It would be prudent to experiment with the materials and methods on hardwood (maple, rosewood, ebony, pau ferro, etc.) scrap before attempting this challenging job.

    Good luck.
     
  4. w..t....f.....wow...hate to hijack the threat but how does one play that thing a small (very very small) drill bit attached to a dremel should do the trick
     
  5. Luke Sheridan

    Luke Sheridan Commercial User

    Dec 30, 2004
    Yonkers, NY
    I build guitars and sell them. Strings, too
  6. Musiclogic

    Musiclogic Commercial User

    Aug 6, 2005
    Southwest Michigan
    Owner/Builder: HJC Customs USA, The Cool Lute, C G O
    The actual way something like this is slotted is by mill, or cnc mill, done with a .025 downcut spur. This can also be done with a metal slotting disc on a foredom or dremel flexible extension. It's a lof of work, and you need to be steady and precise, or goto a machine shop and have it milled for you.
     
  7. 202dy

    202dy Supporting Member

    Sep 26, 2006
    IANAM(achinist).

    Could you post some links for metal slotting discs for the Foredom tool and for a .025" downcut spur? How much work is it to program the CNC or to do it by hand on a mill? Curious about the tooling.
     
  8. koricancowboy

    koricancowboy Ausberto Acevedo Supporting Member

    Jun 10, 2003
    chicago
    Seems like a useless proposition. Just make it fretless and use your ears.:bag:
     
  9. Musiclogic

    Musiclogic Commercial User

    Aug 6, 2005
    Southwest Michigan
    Owner/Builder: HJC Customs USA, The Cool Lute, C G O
    There are various makers of metal cutting wheels for Dremel and Foredom, I would check their sites first. Grizzly also makes small slotting saws.

    As for the mill, most machinists will make their own spur for something this small. One of my friends truns down things like this for a living, he makes micro components for precision milling applications at JPL. I would think you can contact most any mill supply to find a source for the spur, and proper use of an XY table on a verticle mill will do the work nicely.

    Best I can do for you on short notice, I'll try to find more info for you.
     
  10. 202dy

    202dy Supporting Member

    Sep 26, 2006
    Thank you very much!

    If you feel this is getting off topic feel free to send a PM.
     
  11. uethanian

    uethanian

    Mar 11, 2007
    thanks for the responses

    the main problem i have here is that this is for a classical guitar, so i need to cut the slots without taking the neck apart. is there any kind of chisel, pin, or pick that could be used to hammer slots?
     
  12. jeffhigh

    jeffhigh

    May 16, 2005
    you could just use a small circular saw blade on the dremel to cut the slots, and round the tang of the fret at the ends.
    Probably need to set the fret in with CA gel or epoxy
     
  13. 202dy

    202dy Supporting Member

    Sep 26, 2006
    If something is going to be installed into the wood then some wood must be removed. Just like using a nail to start a screw hole, punching slots in the fingerboard will only compress the wood around the slot. When the fret is installed it will cause the fingerboard to bow slightly backward. Installing all the frets this way will create a back bow in the neck that would never come out no matter how strong the truss rod.
     
  14. uethanian

    uethanian

    Mar 11, 2007
    yea, i understand what you're saying about the frets creating backbow. the guitar is pretty bowed already (forward) and it doesnt have any sort of support/truss, but the wood is so old that i doubt it would hold up to hammering.

    so far the dremel sounds good. i had to think about it for a second, but i understand how a circular blade would work in this situation.
     
  15. Angus

    Angus Supporting Member

    Apr 16, 2000
    Palo Alto, CA
    God I would not ever want to use a Dremel for that. Good luck with doing it accurately and cleanly.
     
  16. Musiclogic

    Musiclogic Commercial User

    Aug 6, 2005
    Southwest Michigan
    Owner/Builder: HJC Customs USA, The Cool Lute, C G O

    Actually Angus, if you use a buffer block to allow you to cut on point, and square, it can be relatively easy to do precise work, if you have a steady hand.:bag:
     
  17. Actually you don't need a steady hand:

    [​IMG]

    It's called the ACRA MILL PLUS

    http://www.vanda-layindustries.com/html/acra_mill_plus.html
     
  18. Musiclogic

    Musiclogic Commercial User

    Aug 6, 2005
    Southwest Michigan
    Owner/Builder: HJC Customs USA, The Cool Lute, C G O
    LMAO...and it ain't cheap....LMAO
     
  19. DavidMP

    DavidMP

    May 8, 2006
    Alberta, Canada
    Maybe something like this would work.
     
  20. Angus

    Angus Supporting Member

    Apr 16, 2000
    Palo Alto, CA
    Oh now that's cheating! You're basically routing if you are using a block.

    Then again, I'm a machinist by trade, so any of these setups are truly inaccurate, imo... :spit:
     

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