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Tuner hole location P bass, center to center, and from edge of headstock

Discussion in 'Luthier's Corner' started by Asax, Aug 18, 2018.

  1. Asax


    Apr 26, 2018
    Hi, does anyone know the following measurements:
    1) distance between tuner posts, center to center
    2) distance from edge of the tuner post holes to top edge of headstock.

    I bought hipshot ultralite US tuners with 3/8 posts for my current build. The nut is 4 string with a 1-5/8 " nut width. I drew the string paths of all 4 strings straight and parallel from the nut on my template. None of them touched the post holes on my template in the same spot. If I drill the holes as printed, I'll have 4 strings skewed out in different directions. I'll redraw the holes and try everything in a mdf mockup before drilling my actual headstock.
    Thanks for any help,
  2. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    First thing: The lines of the string paths shouldn't cross the centers of the tuner post holes. You understand that, right? If you are using 3/8" post tuners, then the string path lines should be tangent to a 3/8" diameter circle. That is, they touch the side of the circle. Just like the string contacts the side of the post, then wraps around it.

    If your printed template was drawn for classic 1/2" post tuners, then that shifts everything over 1/16".

    Also, remember that as you adjust the string spacing at the nut, you have to either adjust the tuner-to-tuner spacing, or slightly change the angle of the straight side of the headstock. If you are trying to lay it out for true straight string pull.

    With that said, a classic old Fender-style bass headstock with the big old tuners usually has the post holes 1 3/4" apart, center to center, and 7/8" away from the flat edge.

    More modern Fender-style headstocks using smaller size tuners (like the Ultralites) are often spaced at 1 5/8" apart and 3/4" from the edge. That makes the overall headstock smaller. If you are using mini-tuners, you can go closer and smaller yet.

    If you are laying out a fresh headstock, you can put them at whatever spacing they need to be, for the angle you choose and the nut width/string spacing you choose. Check a pair of the actual tuners next to each other, with the keys flat, to verify how close together you can put them before the keys hit each other. Ideally, you want the keys 1/8" to 1/4" apart.

    Did I mention that doing headstock tuner layouts is a lot easier in the computer using a drafting program? Once you have the tuners drawn in as blocks, it's a lot easier to shuffle them around. There are a lot of variables here. You can do it in pencil too, with a decent sized eraser handy.
    Joshua likes this.
  3. rwkeating


    Oct 1, 2014
    Also consider string gauge (at least to get in the ball park) if you are looking for a straight a pull as possible (without relying on the nut to line up the strings.)

    On my previous instruments I carefully calculated the tuner location (including string gauge) and drew it up it in a CAD program, printed it out and used that as a guide. On all my previous instruments, the strings lined up very well except for the thickest one. On my latest build I added a bit to the offset of the thickest strings and on that instrument they all line up nicely.

    Check out pictures of basses with straight string pull and often you will see the thickest string is off of the straight path. I think it has to do with being less flexible and needing a longer distance to come off the post at a true right angle.
  4. Bruce Johnson

    Bruce Johnson Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    Yes, that's true. I was sticking to the basics in my reply. At the advanced level, you want to include the diameters of the strings, and position the tuners so the side wall of the string is tangent to the tuner post.

    When you get into the complicated headstock layouts, like the 10-string below, it takes some serious computer time to work out the correct tuner positions, and get all the strings straight and parallel. That's why we pro Luthiers make the big bucks! :roflmao:

    JIO and rwkeating like this.

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