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Introduction and a question about neck angle

Posted by Robert Stapleton on March 1, 2015 at 9:54pm in Building Secrets, Tips, Advice, Discussion

Hi,

I'm new to the community - a bass player actually - but recently bought a 3 string CBG and am loving it. Already got an amp and am using it in a few songs with a blues band.

My question is this: does anyone build a 4 string CBG with the neck angle set for low action so that it can be easily fretted (not played with a slide)? What I'm seeing so far is lots of CBGs with high action for slide. Not so many designed for low action. When I get around to making my second purchase I'll be looking for a 4 string that has this feature in particular. Would love to know who those builders are.

Thanks,

Robert

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Replies

  • jim April 5, 2015 at 8:14pm

    you arr kiding right?

  • Robert Stapleton March 6, 2015 at 5:44am

    Richey, I'd be interested to see the inside of one of your boxes if you have a pic you'd share. Someone mentioned putting in blocks that were bigger in the back of a neck through, but I'm picturing the bigger block being in the front to make the neck lean down.

    • The Phrygian Kid > Robert Stapleton March 6, 2015 at 5:50am

      try this http://handmademusicclubhouse.com/photo/thetinyguitarsbodyendscarfj...

      • John Sawyer > The Phrygian Kid March 7, 2015 at 12:46pm

        Bandsaw?

        • gary sheldon > John Sawyer April 5, 2015 at 4:44pm

          NECK ANGLE MATH/GEOMETRY:

          I have always just kind of guessed on neck angle.  Today, I decided to actually figure out how to set it up for a particular angle of neck drop.  And I wanted to make it somewhat simple, so that no trig is involved.

          I used TurboCad, a drafting program to help me.  I constructed a few right triangles with a base of 10".  Drew in the hypotenuse at a couple of 1/2" increments.  At 1/2" the program told me that the angle is 3.11 degrees.  I printed it and checked it with my protractor.  Correct, a little over 3 degrees.  It is difficult measuring those small angles.

          Using a right triangle rather than an isoceles triangle is cheating a bit, but I don't think it makes much difference at these very small angles.

          I was surprised at how big an angle 3 degrees is.  Turns out that my neck drop angles are much less than that.  Maybe half or less.  I also assume that the neck drop angle will change when the instrument is strung up.  How much would depend on the construction method.

          So with a neck through body guitar with 3 plus degree neck drop, the top of the neck at the rear of the box would be cut down 1/2".  That is assuming a 10" long box.  This does not include decrease in neck drop after stringing.  The neck is going to bend some, wood will compress, etc.

          To calculate for different neck drop angles and/or different length boxes you would use a ratio formula.  Going back to the example of the 10" box and the 1/2 inch difference between the ends of the box, we have a ration of 20:1 between the base and altitude of the right triangle for an approximate 3.1 degree neck drop.

          For a different neck drop angle you would use the formula to vary the ratio of base to altitude.

          1 to 20 = 3.1 deg

          2 to 20 =1 to 10 = 6.2 deg

          1 to 40 = 1.55 deg

          Then you have to use another ratio to compensate for a longer or shorter box.  But remember, the ratio and angle will remain constant.

          You can also just draw it out on paper and measure for box length and angle desired.

          Hope this is helpful.

           

  • Robert Stapleton March 5, 2015 at 5:56am

    These are admittedly lo-fi as instruments go, so it's totally understandable that many would want to adhere to the origins and do a basic build. But....they are unique in both sound and appearance and it's also cool to consider making one a bit more deluxe - easier to play, better in construction and sound. There's room for everyone.

    On the deluxe end - I'm guessing that there's a reason that high quality guitars are built the way they are, so there's something to learn there. Thanks for all the input - the conversation is interesting.

  • The Phrygian Kid March 2, 2015 at 10:58pm
    I always pitch my necks, I find it makes it much easier to dial in a very nice action and I also believe that it alters the string trigonometry in a way which in beneficial in terms of tone and volume.
    • Richey Kay > The Phrygian Kid March 5, 2015 at 12:44am

      The Kid is absolutely bang on right here... he kept telling me to try it, and when I finally did, I saw a massive improvement in volume, tone and playability. Nota bene.

  • Slowpaw Steve T March 2, 2015 at 3:11am

    i don't usually build with a high action for slide, only on fretless which appears higher -  i get the action as low as i can sounding sweet on fretted necks  (3mm at 12th), but there is no reason to raise the action fir slide, i can play slide on the lowest action guitars without any problems, it's not necessary :-)

    you don't need to angle the neck, action is determined by nut height and bridge height...but the whole guitar should be straight.

    • Robert Stapleton > Slowpaw Steve T March 2, 2015 at 8:30pm

      Slowpaw Steve: Just curious, would the 3mm be measured from the fretboard or the top of the frets? To the bottom of the strings?

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