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Hello everyone.

I purchased an inexpensive bass guitar online, and when it arrived it had a significant amount of negative relief (backbow). I adjusted the truss rod, setting the neck to have an appropriate amount of relief (about the width of a paper measured at the 7th fret while fretting the first and fifteenth frets on the first and sixth strings). However, the truss rod can only be loosened another half turn before I hear a creaking sound.

I'm rather inexperienced with guitar repair, and need some advice from you fellows. My concern is that 1/2 of a truss rod turn will not leave me enough room for future addition of relief to the neck. This neck needed significant loosening of the truss rod before I saw any response. Is 1/2 of a truss rod turn enough, or should I return this guitar, or even just the neck for replacement (which I am entitled to)?

If anyone could share their experience I'd be grateful.

Truss rods creak and that should not be a concern. Where the neutral point is where the truss rod does nothing and what the neck looks like then, under tension, with the strings that you intend to use is much more important. Different strings have different amounts of pull.

Something else to consider since you are in Toronto and our winter in the midwest, north east was so very brutal is that the instrument may be dry. A dried out gutiar may back bow. If this is the case or even part of the problem rehumidifying the instrument would be a good idea before deciding what you have here.

When running your fingers along the sides of the fret ends do they feel sharp and/or proud of the neck? If so this is a sign of a dry guitar.

Perhaps since this is the neck and not the body that we are talking about leave the isntrument where the humidity is high, basement, etc. for several days keeping an eye on your time limit to return the instrument. Then see what you have.

Thanks for your reply Hesh, and thanks for the info about the truss rod in relation to it's neutral point.

The frets are slightly sharp. The guitar is in the basement in a hard case with a case humidifier. As the guitar regains it's moisture, I'll make sure to inspect the neck.

Hesh, unfortunatly I don't have any formal training on how to determine if the neck is satisfactory. All I've got to go off of are the resources I can find online. This is one of the resources I've been reading, can you tell me if this information is accurate: http://thurmanator.hypermart.net/tgpage ... xneck.html ?

Thanks for your help

You are very welcome VK. I started reading the site that you posted a link to and got all irritated about how long winded the author was/is. If I get irritated because someone is long winded that's saying something.... The author also uses the term "warp" to describe relief - WTF....... Words matter - can you imagine if a surgeon in an operating room made up his/her own terms for surgical equipment. Nurse hand me that thingamajig, no not that what'sitcalled but the thingamajig.....no, no not that side the side with red thingamabob.... nurse, nurse....

Let's keep simple simple. Sight down the neck from the headstock on both the treble and bass side. Ultimately what you want to see with an adjusted neck is a bit of relief (forward bow under string tension and tuned to pitch) on the treble side and a bit more relief on the bass side. Pretty scientific eh.... This is with the rod adjusted, the instrument rehumidified and the strings that you intend to use on this guitar. What I am describing is the goal after adjusting the rod.

If the rod can get your neck to look like this under string tension you are good to go.

*chuckles*

That was simple and clear. Thanks again Hesh.

A couple more thoughts about adjusting a truss rod. First, there are several kinds of adjustable rods - simple threaded tension rods, usually with a nut on the headstock end - they may be straight or curved but by tightening the nut you put the back side of the neck in tension. Older Fenders and Gibsons usually have this kind of rod - loosening the nut allows the strings to pull some relief into the neck, tightening it removes the relief. Loosening too much simply unscrews the nut from the rod, tightening too much breaks the rod, usually at the threaded end.

Second kind is the early Martin single acting rod - the rod is encased in a metal box or has a flat side that pushes up against the fretboard as it is tightended. On acoustic guitars the adjuster is usually inside the sound hole but they can be installed with the adjuster at the headstock. Loosening the nut merely unscrews it and lets the string tension pull some relief into the neck - tightening it removes the relief. You can back bow a neck with one of these.

The third modern rod is the double acting - again, it pushes up on the middle of the fretboard and down on both ends but you can both counter relief and put some into the neck if it doesn't have enough It has kind of a neutral feeling point in the middle of its travel, but gets harder to turn as you go both CW and CCW from that point,

Truss rods are pretty sensitive in their working range - an 1/8 or 1/4 turn can have a lot of effect. Here are two double acting rods - I adjusted each of them dead flat, then gave one a 1/2 turn CW, the other a 1/2 turn CCW. You can see how much effect that has (because of the way they are constrained in the neck it won't have nearly that much effect on relief but you can see that 1/2 turn is a LOT.



btw the shiny part in those pictures goes against the fretboard

Last item is how much relief you need. I don't have much experience with bass guitars but the instruction sheet that came with my little StewMac action gauge recommends 0.014 measured at the 7th fret (hold the string down at the first and the body junction). You should measure with feeler gauges but as a reference a typical business card is about 0.010 - so you are looking at slightly more than one card and less than two.

So, in answer to your question - if you have about that much relief and some adjustment left I would say you are OK