Neck adjustment problems, suspected stuck truss rods

[ricardo_vicente]

I have a rather annoying problem with my new (2009) 330/6.

I have owned and have been playing the guitar for approximately two weeks. I had come to notice some fret buzz on the high E and the B strings. Not so much buzz, but it was clear that they were not vibrating freely and were catching somewhere, i.e. not giving a true ringing note but a short, muted sound.

The action was lowish so I decided to first raise the bridge before having a look at the neck. However I immediately discovered that the bridge was set as high as possible on the side of the high E string.

So I then checked the neck relief. I did this by fretting the first fret and the 17th fret and tapping the bottom E string above the 5th - 7th fret area to see if there was any gap.
The neck seemed to be set rather flat but had some relief. I could have inserted a thin plectrum or a business card between the bottom E string and the frets in that area.
Usually this amount of neck relief is fine and indeed the bottom E, A and D strings were all fine. I was also able raise the bridge on that side a little if I needed. But on the other side the bridge was as high as possible, the action was pretty low but not excessively so and, in general, comfortable to play.

My conclusion therefore was that the truss rods must be unevenly tightened and the side of the G, B and top E strings must need some more relief (possibly even some back-bow n that side). So I took off the truss rod cover.

What I discovered was the following (the pictures below will help to explain what I mean):

1. There is noticeably more of the truss rod on the side of the E, A, D side protruding from the neck cavity.

2. The nut on the truss rod on the G, B, E side was attached to the thread on the truss rod but it was loose. It was not in contact with the washer where the truss rod enters the neck. It wasn't applying any force inorder to hold the truss rod in place.

Effectively there was no way to add relief to the truss rod on the G, B, E side.

I also discovered that the truss rod on the E, A, D side was also pretty close to it's maximum relief setting. I loosened the nut less than half a turn and discovered that it would also come loose and would ultimately screw off the end of the truss rod but the truss rod does not move further into the neck if I did so.

I can tighten the nuts on both sides and successfully reduce the relief (but I don't need/want to).
I can add relief within a very small range on the E, A, D side.
The guitar is playable on the G, B, E side with maximum relief, i.e. the nut loose on the truss rod / no contact between the nut, washer and the small plate at the entry to the neck. But as soon as there is contact in this area and the nut tightens, the strings "catch" on that side again.

To me this means that the truss rods on both sides are stuck in the neck. Loosening the nut should allow them to pull into the neck and add relief. Am I right? At least that's what happens on my other 330/6.

Here you can see the uneven lengths of truss rod in the cavity ...



In both pictures, particularly this next one, you can appreciate how a gap appears between the entry to the neck and the nut on both sides when I unfasten the nuts.



Some more info which might be useful ...

- Yes, I have changed the strings. The strings it came with felt like a standard Rickenbacker set. However, some of the strings were clearly D'Addarios becasue they had the coloured ball ends.
The strings I put on are a standard set of nickel round wound .010 - .046 and being a heavier gauge, if anything, should have added to the tension on the neck, not reduced it.

- The guitar is new but in this case it is technically a used guitar and not under warranty. Returning the guitar to RIC or the dealer is not an option.

I have a local luthier who I could consult but I would just like to ask if there's maybe anythign I can try myself first.
I have so far tried to free up the truss rods by carefully tightening them and lossening them again.
I have also gently tapped each ends of both truss rods but not with any conviction.

The guitar is currently as you see it in the pictures. The nuts are still on the truss rods but completely loose. The guitar has a little too much relief on the E, A, D side but it playable. On the G, B, E side it plays fine like this, but it's obviously not the way to have your guitar set-up.

Would be very grateful for any input. Even if it is to confirm that the fretboard has to come off and the rods need resetting.

[jingle_jangle]

Man, Ricardo, somebody's been messing with that "new" 330! How could the guitar be "new" when it had a mixed set of strings? The weird mix of tensions (and, for all we know, gauges, too) could potentially wreak havoc with the neck's stability.

These are single-acting rods, acting upon the curved top of the rod slot and the fretboard above it, in order to force the neck into a backbow situation and thereby counteracting the string pull, which wants to arc the neck in the opposite direction.

The rods are not "stuck" in their slots, but are generally free to move. The nether end of the rods have a SEMS nut with an integral external tooth lockwasher, snugged onto a cap (acorn) nut, which covers the threaded end and is force-fit into an undersized hole in the end of the neck. This captures and immobilizes the body end of the rods.

Since the rods are already free, they won't go anywhere noticeably when tightened/loosened.

Unless I'm misinterpreting your post, the most worrisome part is the bridge height. The tension on the neck is pulling it into relief, and, indeed, were you to lay the guitar flat on it back on an absolutely flat surface and hold a scale up to the neck at the body end, and also at the nut end, you'd find that the nut end would be about 3/16" - 5/16" higher than the body end. This indicates that the only tension on the neck is coming from the strings, and of course, because the bass strings are higher tension, the relief on that side would be noticeably more than on the treble side.

Loosen the strings completely. Let the guitar sit for a week or so. Do the measurement I've described above, again. Hopefully there'll be less difference in the dimensions at nut and body ends. Snug up the nuts a half-turn after you can feel resistance, tune to pitch, measure again. Repeat tighten/rest, a quarter turn at a time every day or so, until the neck is straight and stays that way for two consecutive measurements. Then set your bridge height. Hopefully it will be closer to the middle of its travel.

[ricardo_vicente]

Many thanks for the reply and practical suggestions, Paul. I will follow your advice and report back.

[jingle_jangle]

I'm looking forward to hearing how it all sorts out, Richard.

[ricardo_vicente]

I'm afraid I misread your instructions and did not make the measurements before loosenign the strings.

However, the guitar has been sat in it's case overnight with the strings loosened (zero tension on the neck from the strings) and the nuts on the truss rod also loosened (not snugged).

I have taken the measurements as suggested and already the neck is the same height at both the body end and the nut end (measured from the floor to the top of the fretboard).

So far, so good(?)

Should I leave the guitar to "settle" like this for a week nevertheless?

[ricardo_vicente]

Yes I'm impatient .... but it's good news.

I went and checked on the guitar again this afternoon. Encouragingly the neck was still flat (at the same height at each end).

So I decided the neck had settled in the right position and that it was time to tune up again.
Even after an hour or so though, the (supposed) tension of the strings hadn't managed to pull the nut end of the neck any higher than the body end. Not to any noticeable degree.

It was then I decided to try a new set of strings. The new strings instantly raised the nut end of the neck to about 2/16" higher than the body end. This enabled me to snug both nuts up by the recommended half turn.
I measured again and found that it gave me a very good flat neck (minimum relief).
The bridge still needs to be up very high (not quite maximum) but the guitar is set up very nicely and the neck is back in some kind of normal balance, with tension from the strings and counter-pressure from the truss rods. No loose nuts!

A quick check after 2 hours or so seems to suggest that the tension from the new strings is still taking effect on the wood. There seems to be a little more relief. I imagine I can expect the strings to progressively pull on the neck and add more relief over the next few days. I suppose I will maybe need to gradually add a quarter of a turn or so for a few days.
Even if this is no the case, the guitar as it is, is set up fine and perfectly playable and it already feels a great deal healthier.

Now the conclusion I draw from all this is that amongst other things, I had a rather rawful set of strings on my guitar which somehow had next to no tension!
Is that possible?

Anyway, thanks again, Paul. It looks like it's going to be a happy ending.

[jingle_jangle]

Well, don't be surprised if you find it's shifted after a day or two. It generally takes much longer for the structure to settle in. But, either way, sounds like you're golden!

[ricardo_vicente]

Just thought I'd pop back with an update now that a week has passed.

The relief on the neck has possibly every so slightly increased. It seems very stable (bear in mind the weather - and in particular the humidity levels - here has been anything but stable!).

The bridge still has to be set very high (still almost at maximum) otherwise the action is too low and there is excessive fret buzz. I find unusual but as it is, it is set up perfectly.

I've not done any measuring but looking at the bridge saddles, they seem to be filed quite a bit deeper than those on my other 330. Depending on the dimesnions of the rest of the bridge components I suppsoe this could be a reason.
But as I say, it puzzles me a bit, but as long as the truss rod nuts are firmly snugged up and I can set the guitar up without any compromise, I'm happy and not necessarily looking for the cause of the "problem".