I've designed this guitar to have the truss rod adjusted at the headstock, so some material has to be removed to provide room for the adjustment nut.
This is done with a chisel and a round file.
However, I can't let it go too high on the headstock or else the trench will leave to little wood at the back of the headstock. So I'm going to have to removed some material on the body as well.
Now the truss rod fits fine lengthwise, but somehow the channel is not quite deep enough. It fit fine when I cut the channel, but now the rod sits a little proud of the surface, and this will prevent a tight fit when gluing the fretboard to the neck. A little work with a chisel and some sandpaper, and the truss rod is below the surface of the neck along its length, and fits snuggly in the channel.
Here's the Allen wrench in the adjustment nut, showing why I had to cut the channel into the headstock almost twice as long as length of the adjustment nut.
Now it is finally time to glue the fretboard onto the neck! But I'll save that for another post.