Fretless Neck Bowing Issue

[Saen Naen]

I have a MIM Fender Jazz Fretless (circa 2002).

Lately I've noticed that there seems to be some bowing in the area from frets 1 to 5. When I look at the neck, the action in the higher registers is much higher than in the lower.

I tried to adjust the truss rod, but it just resulted in a lot of buzzing from frets 1 through 5. I also notice that when I depress on fret 8 or 9, the string lays on the fretboard at about 5, 6 or 7th fret and buzzes.

A couple of details about the bass: I string it with light gauge strings in standard tuning, the fretboard has been coated with epoxy. A while ago I had taken the neck off and replaced it with a fretted neck, played it like that for a while and then put the fretless neck back on it. I recently got it back from storage after a move, and before now I hadn't played it in about a year.

I think that taking the neck off for that short period of time had maybe caused the neck to warp. There were no extreme temperatures where it had been stored, so I am not sure.

Anyone have any advice?

[ridgeback]

http://www.tunemybass.com/bass_setup...ck_relief.html
have a look ...

[Saen Naen]

Adjusting the truss rod only changes the action universally across the neck. It doesn't seem to get rid of the uneven spot where the bowing seems to start.

I would have to raise it quite a bit to where there is no buzzing in the lower frets, but then my action would be way to high and uncomfortable to play.

[ridgeback]

is the epoxy put on even???it might look and feel ok but if there are high /low spots it could be adding to your problem!!also check the hight of the stings at the nut..i had a similar problem on my musicman where the strings were to low at the nut caused all kinds of bother...
why did you put epoxy on the neck?i know to save it from wear but honestly i use .45 stainless rounds on my fretless and the wear is so slight even after heavy use!!

[202dy]

When the neck was in storage, was the truss rod brought to a neutral position so that it exerted no stress on the neck?

[Saen Naen]

Originally Posted by ridgeback

is the epoxy put on even???it might look and feel ok but if there are high /low spots it could be adding to your problem!!also check the hight of the stings at the nut..i had a similar problem on my musicman where the strings were to low at the nut caused all kinds of bother...
why did you put epoxy on the neck?i know to save it from wear but honestly i use .45 stainless rounds on my fretless and the wear is so slight even after heavy use!!

The epoxy coating seems to be pretty even. When I first had it put on (when the bass was fairly new and played often) it was definitely smooth across the whole fretboard. I had it put on to get a more biting tone. It's a rosewood fretboard.

The action is pretty low at the nut however. I suspected maybe having to get a replacement. Do you have a material or brand of nut you would suggest?

@ 202dy - When I took the neck off I did not adjust the truss rod. I was not aware of that fact. How do you tell what neutral position would be?

[202dy]

Originally Posted by Saen Naen

The epoxy coating seems to be pretty even. When I first had it put on (when the bass was fairly new and played often) it was definitely smooth across the whole fretboard. I had it put on to get a more biting tone. It's a rosewood fretboard.

The action is pretty low at the nut however. I suspected maybe having to get a replacement. Do you have a material or brand of nut you would suggest?

@ 202dy - When I took the neck off I did not adjust the truss rod. I was not aware of that fact. How do you tell what neutral position would be?

First of all, it is highly unlikely that this neck is warped. However, it may have set into an unacceptable shape from a relief standpoint. All is not lost.

The neck is a balanced system. The neck is under tension when strung to pitch. The truss rod places the neck in compression to counteract the load of the strings. When the load is removed (guitar strings removed, neck removed, etc.) the truss rod should also be brought to a neutral or relaxed position so that it no longer has an effect on the neck. A single action truss rod is easy to relax. Simply loosen the truss rod nut until it is loose. In a double action system it is a little trickier because it is necessary to "feel" when the nut is loose or in between the two positions. If you play with it a bit you'll quickly get a feel for it.

You indicate that the strings laying on the frets behind the stopped note. Given all of this, my guess is that your neck is in a back bow. If the neck has a double action truss rod, it is a simple fix to turn the nut until there is more relief. With a single action truss rod, it can be a little more grief.

First, loosen the truss rod nut. See if this will bring the neck into relief. If it does, all is well. The relief can be fine tuned from there. If it does not, then the neck will have to be clamped into relief, or have a heat treatment. These are more advanced repair methods and should be only considered if one is handy in the extreme.

[Saen Naen]

@ 202dy - I tried what you suggested about loosening the truss rod nut.

I slacked all the strings and loosened the nut out almost all the way. I let it sit for a little while, gave it a slight crank of tension, then tuned the strings back up.

For the most part the action was even although really high. I gave it a little less than a quarter turn tighter on the truss rod and then adjusted my bridge to the action I wanted.

I played it for a good 15-20 minutes and did not feel or hear any buzzes. Oddly enough, there were only a few on the 2 or 3 highest frets of the A, D and G strings. Nothing too wacky though.

I figure I'll have to adjust again next time I pick it up in a couple of hours. But all in all it seems to be playing a lot better.

Thanks for the advice. One more thing I've always wondered about: is it bad to hang basses by their headstocks using those wall mounted hooks?

[ridgeback]

nope i have always done it and never had a bother..had one on the wall since 1992 and only took it down when i moved to denmark 2 years ago and its still as perfect as when i put it there..

[Saen Naen]

A quick update -

After letting out all the tension in the truss rod and re-tightening from the starting point, I seem to have gotten rid of the back bow. I am still tweaking it to find the perfect action height. Truss rod adjustments seem to catch up after a few hours.

I took the bass off the wall this morning and it seemed to have stayed at a decent height. Still high, so I turned it a bit tighter and adjusted the bridge accordingly. It's in a slight foward bow now, and it makes some of the notes in the higher registers hit the very edge of the neck (around the last fret area). If I lower the bridge anymore than it is, it gets worse.

I'll just keep my ear on it and tweak when necessary.

[Rick Auricchio]

You are correct that truss-rod adjustments take time to settle in. That's why it's recommended to go no more than 1/4 turn at a time, then wait for results.

In most cases, relief is very slight, invisible without a straightedge. To check it, fret a note at the first fret position and about where the neck meets the body. (Use a capo for the high position.) The string is thus your straightedge.

Now measure between string and neck at about the seventh fret. Relief varies among instruments, but it shouldn't be more than a credit-card thickness. Some players prefer even less, down to .010 inches, depending on playing style and the neck.

A technique that doesn't need a capo is to fret at first fret and use your elbow near the pickups to jam the strings down against the neck. Now your right hand is able to reach the seventh-fret area to tap the string against the neck.

Gary Willis' setup guide is helpful and easy to follow.