GIbson J-200 Truss Rod Replacement
This Gibson J-200 came to us from the Musician's 1st Choice in need of a truss rod repair and refret.
One of the issues with this guitar was that the neck was very flexible. Pushing down on it with one finger, as shown in this image, was enough to cause bending (there are several reasons this is happening that we will address throughout this post).
In an effort to fix the flexing in the neck, a previous owner had tightened the truss rod so much that the wood in the neck had begun to compress and split apart, seen here. We will need to replace the truss rod to ensure it can work properly. We will address this cracking once that has been completed.
In order to do replace the truss rod, we will need to remove the fretboard from the neck. We do this by applying heat and slowly working the two pieces apart.
We also drilled small holes at the first and thirteenth frets for index points to glue the fret surface back on later.
We also had to remove the faceplate from the headstock but, we cannot apply heat directly to it, as we could with the fretboard. Direct heat would damage the finish so, we heat up a knife and work at the glue from the side.
We then apply heat to the neck to loosen the glue holding this block of wood over the truss rod. Once this is out, we can get to the truss rod itself.
Here, you can see the metal washer around the truss rod has been pushed beyond the slot it would normally sit in. It has been pushed so far that it has compressed and split the wood in the truss rod channel. We will remove this old rod and clean out the channel of the broken wood.
One of the issues that caused the neck to be so flexible and the truss rod to not be as effective is the depth of the truss rod channel itself. Here we are measuring the depth from the top of the neck to the back of it. We can see it is 0.6255 inches.
Here, we are measuring the depth from the top of the neck to the bottom of the truss rod channel and getting 0.5230 inches. From the bottom of the truss rod channel to the back of the neck, there is less than 1/8" of wood. Structurally, this doesn't do much for the instrument so we will build this up a little before replacing the rod.
After cleaning up the channel, we block it off and fill it with epoxy. This will help provide more stability and a base for the new rod.
We rout out the channel to provide a uniform surface for the new rod. Another issue that had prevented the previous rod from working properly was that this channel had been routed straight. Typically, a single action truss rod channel would be deeper towards the middle of the neck to allow the rod to slack and tighten appropriately. With a uniform depth, the rod is forced to stay straight and not function as it should.
The last issue that was effecting the old rod was that glue had seeped into the channel, preventing it from being able to move properly when adjusted. We mitigated all of the previously mentioned issues by building up the bottom of the existing truss rod channel and then using this single action U-channel truss rod which we are gluing in place here.
We went this route because the rod itself is housed in an aluminum chassis which has the required curvature for the rod to function built into it. This housing also prevents any glue from getting to the rod inside and also provides a lot more rigidity to the neck to prevent the flexing seen earlier. Lastly, the truss rod bears against the chassis when in use so, no matter how much it is tightened, it will not damage the wood around it. Once the new rod is in place, we glue the fretboard back on.
This was a pretty standard job as far as frets go. Once this is completed, we will then refinish the back of the neck and headstock to address the crack caused by the old rod.
Here, you can see that with the help of the indexing points in the first and thirteenth frets, refinishing the neck provided a seamless result.
Here you can see the new finish on the neck and that the crack has been closed and covered. This guitar also got new tuners after it left the shop. One thing special to note is that with the refinishing of the neck and headstock, we were able to retain the integrity of the serial number.