Nashville
Open menu

How to Adjust the Neck with an Adjustable Truss Rod

Download the guide (PDF)

Your guitar’s neck can be adjusted.

Inside the neck, there is a metal rod called a truss rod. It helps keep the neck strong and allows you to fix any bending or warping.

Because guitar strings pull tightly on the neck and weather can affect the wood, sometimes the neck may bend slightly or develop a small hump. This doesn’t happen often, and it’s not something to worry about.

If it does happen, you can fix it by carefully following the adjustment steps explained below.

Not every guitar has an adjustable truss rod — many classical guitars don’t. If you can’t find an adjustment nut at the headstock or inside the sound hole, your guitar may not have one; ask your dealer before attempting any adjustment.

Types of Adjustable Truss Rod

Diagram of a guitar neck showing the truss rod inside it, with the adjustment nut either at the headstock (Headpiece type) or at the body end of the fingerboard (End-of-Fingerboard type).
Headpiece type: the adjustment nut is at the headstock, under a small cover. End-of-Fingerboard type: the nut is at the body end of the neck, reached through the sound hole on acoustic guitars.

Step by step

  1. 1

    Hold the guitar neck up to eye level and look down the edge of the fingerboard on both sides. This will help you see if the neck is bending (a bow) or has a raised area (a hump).

  2. 2

    Loosen the 3rd and 4th strings slightly, but do not take them off the guitar. Move the loosened strings to one side so you can clearly reach the adjustment nut — inside the sound hole on End-of-Fingerboard types, or at the headstock on Headpiece types.

  3. 3

    For Headpiece type guitars: remove the cover at the head of the neck to reveal the adjustment nut underneath.

  4. 4

    Insert the hex wrench firmly into the adjustment nut to make sure it fits securely before turning.

  5. 5

    If the neck is bowed (curved forward), tighten the nut by turning the wrench clockwise, as seen when facing the nut.

    A neck with a forward bow in the middle, which raises string action and hurts intonation. Turn the wrench clockwise to tighten.
  6. 6

    If the neck has a hump (curved backward), loosen the nut by turning the wrench counter-clockwise, as seen when facing the nut.

    A neck with a hump in the middle, which causes string rattle and false notes. Turn the wrench counter-clockwise to loosen.
  7. 7

    Turn the wrench slowly and in small steps — just a little at a time. After each small turn, check the neck to see how it’s changing.

Retune the 3rd and 4th strings to pitch and check the neck again. Most guitars play best with the neck almost straight, keeping a very slight forward bow (called relief) under full string tension. If needed, repeat with another small turn.

Caution: Do not overtighten the adjustment nut. If it starts to feel hard to turn, stop. Forcing it can damage the threads or even break the truss rod.

If in doubt, have your dealer or a qualified guitar technician make the adjustment. Truss-rod adjustment is routine maintenance and isn’t covered by the warranty, and neither is damage from over-tightening or forcing the nut.

Questions? Contact your authorized dealer, or send us a message. See also the warranty terms.