Six String Bass Questions

Discussion in 'Luthier's Corner' started by andvari7, Sep 6, 2004.

  1. andvari7


    Aug 28, 2004
    My project is going to be (once I'm able to get to my tools) a six-string bass (probably fretless). However, before I begin, I have a few questions:

    1. Since it's going to be 38" scale (I know, I'm crazy), what kind of truss rod would I need?
    2. The goal, aside from making it sound nice, is to make it as light as possible. What kind of bridge would help?
    3. The 38" scale brings up some additional neck questions: How long will the neck have to be, and what would be a good width at the 24th fret equivalent?
    4. Anything else I missed? Believe me, I will take ANY suggestions.
  2. FBB Custom

    FBB Custom TalkBass Pro Commercial User

    Jan 26, 2002
    Owner: FBB Bass Works
    I'll assume you have a good reason for wanting a 38" scale instrument.

    Most suppliers sell 24" truss rods. This will leave you with a good amount more neck than a 34" scale that is unsupported by the truss rod. Unless you feel like making your own, you are pretty much stuck with 24". I would use 2.

    The longer scale instruments move the peghead away from the body and shift balance towards neck-divey instruments. Trying to remove weight where you can (the body) will exacerbate this problem. Aluminum bridges are lighter than brass (by a significant amount), and wood is probably just as light (classical-style bridge), but every ounce you shave from the body is going to contribute to neck-heaviness unless you go headless.

    Strings are going to be a bitch to get for this bass, and I hope you have long arms and fingers.
  3. Most of this would be answered by creating full size drawings of your design.
  4. andvari7


    Aug 28, 2004
    Thank you for these suggestions. I have finally figured out what I'm going to do, but I still have two more questions.
    1. How much room do I leave on the sides of my neck for clearance?
    2. Is there some program or formula I can use to calculate such?
  5. rdhbass


    Jun 28, 2003
    Springfield, mo
    I'm not meaning to sound negative but I think its pretty weird to want a neck that long. I know its good to dare to be different, but there are veteran and I mean real top players who have to my amazement never even switched from the simple 34" scale 4-string. All you're getting anyway is a few higher notes, so why not go with a 7 string or 8 string (not doubled strings) bass in like a 35-36" scale? Same difference.
  6. andvari7


    Aug 28, 2004
    Actually, I'm getting the same notes as any 24-fret six-string bass. I just want to have a different bass than what's normally available. And I'll still play 34" scale - my next two basses will be that scale.
  7. Bass Kahuna

    Bass Kahuna

    Dec 3, 2002
    West Lafayette, Indiana
    Luthier, Custom Builder
    Not sure I understand the question.

    As far as your first set of questions go, Hambone is absolutely correct. Before doing anything make a full scale drawing of the bass you want to build. Make one from the side and one from the front. The side one should include the dimensions of the bridge, pickups, etc., so that you can be positive that once you start building the bridge and pickups (and other hardware) will be able to work within the confines of what you've built (ie:the bridge will be able to be adjusted high enough or low enough for the type of setup/action that you want... you'll know how deep to route the pickup cavities, etc,. etc.,,,).
  8. Brendan


    Jun 18, 2000
    Austin, TX
    Knuckle makes 39" scale basses.

    Maybe you should ask Skip at Knuckle, Andvari?
  9. andvari7


    Aug 28, 2004
    Thanks, but I'll stick to my DIY bass.

    Anyway, I have yet another question:

    How long should the headstock be? I assume the maximum width should be the width of the fingerboard at the 24th fret equivalent, and the thickness be determined by the tuners (which will be Sperzel).
  10. The size of the headstock will be deteremined by the placing of your tuners. Plenty of basses aren't limited by the width of the original neck blank, all you'd need to do is glue on extra pieces where you need the width.

    I think what Andavri7 was trying to ask regarding the clearance on the sides of the neck was refering to how much space you have between the edge of the neck and your string centres (if that made any more sense). I've allowed 5mm (slightly less than 1/4") on each side because thats what both my Yamaha's have and they're fine.

    Syberslack, its not just higher notes you can get because as the scale increases, so does the size of the frets. Knucke's are tuned an octave below your standard 4-string tuning. And I was reading around the Carl Thompson website (I think it was his) a while back and he said that he found the the tone of the longer scale was different to the normal, particularly in the upper regions.

    I was keen to make a really long scale but I know little about making a bass that will be comfortable with a normal scale, let alone 38". If you're hoping to take a standard jazz body design and whack ~30" of neck on instead of a normal jazz neck, you're going to have one ugly and poorly balanced bass.

    Josh D
  11. andvari7


    Aug 28, 2004
    Don't worry, I've already taken care of the design issues.

    New question:
    How do I go about making a 1/2" diameter steel slug for the end of a truss rod? It needs a 10/32" threading to accommodate the rod of that threading.