Just a quickie.
Sometimes, you’ll try to adjust a truss rod and it’ll feel… ‘wrong’. Maybe it’ll be a little hard to adjust or it might just feel ‘gritty’ or reluctant to turn.
Trust your instincts on this. Don’t force it.
Here’s an easy little trick that will often help.
Before you tighten it, loosen it. This on its own can sometimes be enough to free things up a little.
However, even better, is if you remove the adjustment nut completely. Then, clean the threads in the rod and nut as best you can. A small wire brush is helpful but be careful of the headstock finish.
The pièce de résistance… Lube it up.
A little grease or Vaseline works wonders. Don’t go crazy with it but work a little into the threaded hole in the nut and even leave a thin film on the nut’s ’face’ (where it bears against the neck).
Screw it back on and you’ll probably find things much easier to adjust.