Why The Bullet Truss-rod?

Discussion in 'Basses [BG]' started by Acoop, Jun 13, 2019.

  1. Acoop

    Acoop Supporting Member

    Feb 21, 2012
    Back in the 70's I had a 68 Jazz bass and the truss rod started lifting at the end or the first fret. It never popped through but, it did crack the inlay. My guess is, this became a big problem for Fender and eventually, (1975), redesigned the J-bass and Strat design to the bullet truss rod. ... Curious if any one else has a different take on it?
  2. SteveCS


    Nov 19, 2014
    Hampshire, UK
    It is difficult to adjust the truss rod from the heel without removing the neck. Maybe with the earlier design, Fender assumed they could preset the neck at the factory as the variety of string types/gauges were very limited so user adjustment was considered unnecessary. As more string types and gauges became available the need to facilitate easier user adjustment arose, and headstock adjustment was the an easier solution than re-jigging for additional body routes. YMMV
  3. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    I'm not sure why Fender put the bullet nose on the truss rod nuts. It could be because of the process they used to make the hex socket on the end. They may have crimped the steel around a hex arbor, which would leave the OD rough. So, they turned the excess metal into the bullet shape to clean it up. These days, hex sockets are cut by a process called Rotary Broaching. But, back in the '60's, I don't think rotary broaching was in much use in machine shops.

    When a Fender truss rod starts lifting up the inlay or the fingerboard, that's the square washer on the end of the rod doing the lifting. When you overtighten the Fender Truss rod, the wood behind the washer starts crushing. And it usually starts smashing unevenly, tilting the washer at an angle. Then the washer starts slipping upwards and pushes up against the underside of the fingerboard. Keep tightening it, and it will push up the inlay or a section of the fingerboard.
    Last edited: Jun 13, 2019
  4. Acoop

    Acoop Supporting Member

    Feb 21, 2012
    Bruce Johnson, thanks for that.
    Okay, but when the truss adjustment is at the heal the truss only runs as far up as the first fret, correct? ... I've done a lot of bass work but never replace a fretboard. ... And you're saying at the end of the truss, when at the first fret there's a washer there? ... I know another bassist who had the same problem and he told me his father and him removed the inlay and managed to force the truss rod back down and fixed it. ... Whether it stayed that way I have no idea. ... Now, I have a 74 Jazz and there is no problem with the truss lifting. ...