Truss rod problem solved

[7string]

I've had this problem with my Carvin 5 string and I managed to fix it. It's a common problem with older guitars and basses, so I thought I'd post it here.

I wanted to setup the bass and give it a good clean at the same time. This is what I found under the truss rod cover.



The wood is compressed in the truss rod channel and someone had used a big washer and a regular hex nut to fix it. The rod was really tight and the neck still needed to be straightened a bit, so something had to be done.

The solution was to make a wooden washer to take up the slack, then put the washer back and put a Gibson acorn nut of the end as n adjuster. I've asked Carvin what they use but so far I haven't received a reply. The acorn nut fitted so I decided to go with that. To make the wooden washer, I cut a slice of wood, drilled 4 holes in it (in case I made a hash of the first one) and cut a quarter of it out. I then shaped the piece with a Dremel.



Here they are all fitted. The next problem was that the truss rod adjuster wouldn't fit in the cavity, so I slotted the top of the acorn nut and used a screwdriver to tighten it up. Then I found that the truss rod cover wouldn't fit as the edges of acorn nut were too high. The Dremel came out again to grind down the high bit. That was then tidied up a bit.



The neck was bent into a backbow and the truss rod nut tightened up. This took the relief down from .030" to 0.014"

Job done.

[geoffbyrne]

Good job well done - I love a bit of applied know-how!!

G.