If your guitar neck has a back bow, then there will be a high spot in the middle of your neck will. A back bowed neck can cause all sorts of intonation and playing problems, including fret buzz, so if you have one, it’s the first thing you’ll want to fix as you run you guitar through a setup.
The normal cause of back bow is an over-tightened truss rod. That is, your truss rod is too tight and is exerting too much pressure on the neck. In order to remedy this, you’ll want to loosen the truss rod and allow the tension exerted by the strings to pull the neck forward.
Now it’s time for the actual adjustment. Use a hex key or socket wrench to do this. (The type of tool you use here depends on the truss rod in your guitar).
1. First, if you have a truss rod cover, you’ll want to remove it.
2. Now, loosen your truss rod with your hex key or socket wrench by turning it a quarter turn or so counter clockwise.
3. Use a straight edge to see if you were able to remove the back bow from your neck. (“Physical Assessment,” in the previous step.)
4. Continue steps 1 and 2 until the back bow in your neck is gone. (Be careful not to over do it). If you loosen it to much, to the point where theres no tension on the truss rod at all, the nut your tightening could begin to rattle when playing. So make sure the nut is left snug. If the neck still has a back bow, you have more serious issues. You either heat up the neck and force it into a straight position or pull the frets or sand the fingerboard level and refret. These jobs are for another show.
5. Now you’ll want to do one last check to make sure you didn’t loosen your truss rod too much (this would cause a forward bow). Repeat the “Physical Assessment,” explained in the previous step.
6. Okay, last step. Do one more visual assessment on you neck to be sure you’ve completely eliminated any back bow and haven’t caused any other neck problems.
Now that you’re done adjusting your neck, you can continue running through the setup.
- Tip -
Some luthiers suggest letting the neck rest overnight before continuing the setup. This will allow the neck to settle into its new tension position.