How can I put some relief in my gutar neck with this trussrod?

Question

I have many years experience in working on guitars. I am usually a very good truss rod adjuster as I understand fully the function of the truss rod and I usually like a little relief in my fretboards by getting the neck sraight with the strings at pitch, then I back off the nut about a quarter turn usually will be enough to put a little relief in the neck.
I currently am working on a Jackson that has a perfectly straight neck. I have loosened the trussrod completely until now the nut is off completely, and the neck is still straight with no relief with the strings tight to tuned pitch. Why is the neck not being pulled into a slight bow by the strings. I have been told to try a heavier guage string but even going to ten's has not worked. I have never ran across any neck that did not allow the strings to pull a bow into the neck when the trussrod is completely loose. How can I put some relief into the neck with this trussrod loose and the neck is still straight? What is going on?

Answer 1

I had this experience recently with a Guild jumbo acoustic guitar. Eventually, a little relief developed in the neck - but it took a couple of days.

While it's hard to give an answer with certainty, remember that the truss rod *augments* the neck's natural stiffness. The rod alone is not the only reason why the neck stays straight. So it could be that the neck (hard rock maple?) is quite resistant in and of itself.

When you wrote "even going to tens" I grinned to myself, because as a jazz player, 10's are still very light. 11's might make the neck move a little, but you never know. If it were me, I would make sure the truss rod wasn't *totally* loose - just turn it til you feel slight resistance, then stop.

I know this isn't a real answer! Good luck, and perhaps now you can appreciate why some instruments have truss rods that apply pressure to the neck in both directions.

-Roger