neck pocket size?

Discussion in 'Luthier's Corner' started by markusd, Jun 13, 2019.

  1. markusd


    Jun 13, 2019
    Hi there,

    I am planning my own bolt on bass and I wonder if the size of the neck pocket effects the sound and if there are minimum measurements that shouldn't be undercut.

    Why I ask?

    I plan to build a 4 string fretless with 24 frets. To make the higher frets economically accessible I try to come as close as possible to the 24th with the cut out and also try to avoid a big chunky plate as on a fender e.g.

  2. Arie X

    Arie X

    Oct 19, 2015
    on a bolt-on, the pocket should conform to the geometry of the neck as it terminates at the body. basically the taper of the neck comes to a terminus at the neck pocket.

    you need to also have a small gap at the butt end of the tenon and the neck pocket to allow for expansion of the body and neck as they react to humidity changes. too tight and you'll have that typical spilt at the treble side cutout. a small fretboard extension in this area conceals the expansion gap very well.

    tone wise, you'll want clean precise woodwork. the floor of the pocket and the bottom of the tenon need to be true and flat with no gaps for maximum string energy transfer. the neck should push in with your fingers with around a .005 to .008 air gap at the butt end. if you have to tap it in with a mallet it's too tight. when humidity changes and your woods settle in, it'll come down to body vs neck and the neck always wins -and you'll see that result with a crack in the treble side cut-out.
  3. markusd


    Jun 13, 2019
    thank you for your explanations! They help me a lot to know how tight the neck should fit :)

    I might have expressed my question a bit confusing.
    What I worry about is the length of the Pocket in the body, the bed on witch the neck sits on.

    As I designed it now it is 6cm/2.36" on the G-String and 10cm/3.9" on the E-String.
    Just wanna be sure it is not too short.

    Due to a quite deep gut out for easy accessibility to the 24th fret I will extend the Neck beyond the fretboard already and cover it with a ramp anyways.
  4. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    My general rule is that I like bolt-on bass neck pockets to be at least 3 1/2" long, for stiffness and structural strength. That's the "safe" number. You can build basses with shorter neck pockets than that, but you have to be careful with the thickness of the body wood under the pocket, body wood choice, security of the neck screws/bolts/inserts. The shorter the length of the pocket, the higher the load on the screws/bolts.
  5. Arie X

    Arie X

    Oct 19, 2015
    generally around 1.25 to 1.5x the widest portion of the tenon. body wood under the pocket: minimum 1x the neck and fretboard max thickness at the tenon.

    fwiw, neck-throughs eliminate a lot of these concerns.