Repairing a Broken Truss Rod
So you go to adjust the truss rod in your vintage Gibson and the the nut just threads down the rod and slowly pulls it out of the neck. Hopefully the rod is just snapped at the end very close to the nut itself. If that were the case we could just recut threads and sink the nut 1/2 inch or less into the neck. On this guitar the rod was broken from its anchor at the heel. Heres how Its done without removing the whole fingerboard.
The Rod is loose and can be pulled from the neck.
I chose to remove the inlays. This guitar was made in the 60s and the inlays are made of celluloid instead of pearl. The heat that I am about to apply would damage them.
Once the inlays are out and the bindings in this area are loose I use a small iron to heat up this part of the fingerboard.
I used a magnet to find where the rod ended. Then removed a fret before that point. Then used a small saw to cut through the fret slot.
Thats the anchor that has snapped off from the rod.
The broken business end. I decided to make another rod and anchor.
Im threading both ends of the new rod. The new square anchor will be drilled and tapped to match.
The new anchor is dropped into the mortise I cut. the threads in the anchor I coated with a thread locker. The rod goes back into the neck and threaded into the new anchor.
Once the section of the fingerboard, inlays and binding are re-installed the repair is invisible. Now this old guitar has a great working truss rod!