Can't tighten truss rod nut on Geddy any further

[SeismicAssault]

I've been working on setting the relief on a Geddy Lee jazz bass neck that I purchased off eBay, and I'm running into some problems lessening the relief on the neck. Right now, when strung up with 40-100 strings, I have about 0.02" of relief at the 8th fret. It's not bad, but I'd like to get it a little lower, maybe closer to 0.012".

So I took the neck off the body to try to adjust the truss rod nut. I first backed the nut off about 1/8 a turn (counterclockwise) to make sure it wasn't seized. Worked fine. Then I turn it clockwise abou 1/8 a turn, and after that, it starts getting much harder to turn. When I look at the relief with the neck off, there's a little bit of back bow (negative relief), so I believe I should be able to tighten the truss rod nut without meeting much resistance.

I completely removed the truss rod nut to see if I could see anything, and everything looks fine. I sprayed a little WD40 in there to make sure the threads were good, and put the truss rod nut back on. Tightened the truss rod nut to where it becomes difficult to turn again, and put the neck back on the body, restrung, and still have the 0.02" relief.

So I think I've got one of two conditions occurring.

Either A: The truss rod has been straightened out as far as it will go, so tightening the truss rod nut any more will either compress the wood or snap the truss rod. I don't think this is what is occurring.

Or B: The truss rod is inserted all the way into the truss rod nut ... basically I can't screw the nut on any further because the truss rod is hitting the back of the truss rod nut. I think this is possibly what's happening.

If it is case B, should I be able to give myself a little more truss rod adjustment by simply installing a washer on the truss rod before putting the truss rod nut on?

Thanks for reading my long post and offering any assistance. Just for your information, I know that a lot of people will recommend taking this to a repair technician, but I'm pretty handy with guitars, and I'm hoping I can solve this myself.

[mongo2]

Originally Posted by SeismicAssault

I sprayed a little WD40 in there to make sure the threads were good, and put the truss rod nut back on.

Personally, I wouldn't have done that.

Originally Posted by SeismicAssault

If it is case B, should I be able to give myself a little more truss rod adjustment by simply installing a washer on the truss rod before putting the truss rod nut on?

That I would do.

[SeismicAssault]

Originally Posted by mongo2

Personally, I wouldn't have done that.




That I would do.

So I just took the truss rod nut off again, and before I tried putting the washer on, I measured the length of the actual truss rod that is accessible to the truss rod nut. There's about 1/4" sticking out. I screwed a 10/32" bolt into the truss rod nut, and that went in about 1/2". So I definitely don't think B is happening. The truss rod is definitely bottoming out inside of the truss rod nut.

So now I'm not sure what is going on.

I guess I can put the nut back on and try cranking a little harder ... I don't think this is the right path, though.

For some reason it feels like the truss rod is completely straight or something. So cranking on the nut just wants to compress the wood. I thought (from the reading that I'm doing) that the truss rod is normally curved a little, and as you tighten the truss rod nut, it tends to straighten the truss rod a little. Then when you add tension to the neck by putting the strings on, the neck wants to start to bow, but it hits the trus rod and stops bending. Is this correct?

[Matt R.]

Dude, take it to a repair guy and have it looked at

[Bassmickeyd]

You should be able to flatten that sucker so the strings are against the board. ..... Anytime I've run up against that it's wood shavings inside the screw hole cavity. You haven't told us where you live so if it's at the north pole???? Anyway I think you can figure this out and at all costs contact Fender repair for help. ...... All companies have guys sitting around waiting by the phone for you call.

[SeismicAssault]

Originally Posted by Bassmickeyd

You should be able to flatten that sucker so the strings are against the board. ..... Anytime I've run up against that it's wood shavings inside the screw hole cavity. You haven't told us where you live so if it's at the north pole???? Anyway I think you can figure this out and at all costs contact Fender repair for help. ...... All companies have guys sitting around waiting by the phone for you call.

No, I live in New Hampshire, USA. ...

Yeah, I'd like to figure this out myself.

The only other thing I was thinking of trying was to put some clamps on the ends of the neck, and a block in the middle, and try to "backbow" it a little more, and tighten up the truss rod then. The thing is, with the strings off, it already has a slight backbow, so I don't think doing more will help anything.

Is it possible that the threads of the truss rod are just a little corroded, and I'm starting to hit the corroded part?

[Tusec]

Here are some great pics (including X-rays) of Fender trussrods to help visualize what's going on:

http://www.timeelect.com/54-neck.htm

The channel that the truss rod sits in has a pronounced curve -- so pronounced it's doubtful the rod would ever fully straighten even when fully tightened. So scenario A is out. And your measurements with the bolt and the available rod length seem to rule out scenario B.

I think you're right that it's bottoming before getting to the end of the nut. The wood chips in the threads theory seems plausible, or maybe glue in the threads, or maybe just corrosion on the threads.

It seems like your only options short of more major surgery are to crank it or add a washer. I've had success with cranking it, but that's risky, and since you're pretty close to being where you need to be relief-wise, the washer seems like the better bet. That might get you another turn or so of tension, which is likely to be all you need.

[king_biscuit]

Maybe have a qualified tech take a look at it. Also, throw the WD40 out; that stuff is worthless as a lubricant.

[SeismicAssault]

Originally Posted by Tusec

Here are some great pics (including X-rays) of Fender trussrods to help visualize what's going on:

http://www.timeelect.com/54-neck.htm

The channel that the truss rod sits in has a pronounced curve -- so pronounced it's doubtful the rod would ever fully straighten even when fully tightened. So scenario A is out. And your measurements with the bolt and the available rod length seem to rule out scenario B.

I think you're right that it's bottoming before getting to the end of the nut. The wood chips in the threads theory seems plausible, or maybe glue in the threads, or maybe just corrosion on the threads.

It seems like your only options short of more major surgery are to crank it or add a washer. I've had success with cranking it, but that's risky, and since you're pretty close to being where you need to be relief-wise, the washer seems like the better bet. That might get you another turn or so of tension, which is likely to be all you need.

I don't think a washer is going to do anything, though. If the truss rod isn't bottoming out inside the truss rod nut, I don't think it would help out at all.

I guess something could be clogged up in the threads, but I'm pretty sure the nut start getting tight right when it hits the anchor. Could the truss rod be seized up inside the anchor for some reason?

I tried spaying WD 40 on it last night (in case it was either seized up or there was corrosion on the threads), but it doesn't feel any different tonight. Would some anti-seize lubricant be a good idea?

[SeismicAssault]

Originally Posted by king_biscuit

Maybe have a qualified tech take a look at it. Also, throw the WD40 out; that stuff is worthless as a lubricant.

... we must have been typing at the same time ... you're the second person that says "Nay" on the WD 40. How about anti-seize?

[SeismicAssault]

Do you think doing something like this might help out some?

http://www.youtube.com/watch?v=e2HGn7c9_uo

With the strings loosened, it's already got a little backbow. This might help give it just a little more, enough that I can tighten the truss rod nut just a little more, and take that last little bit of relief out.

[king_biscuit]

Originally Posted by SeismicAssault

... we must have been typing at the same time ... you're the second person that says "Nay" on the WD 40. How about anti-seize?

If you can get the nut off, you don't need anything like that -- PB Blaster is the best antisieze, btw! Just use a little bit of Vaseline to lubricate the threads. Other than that, grease is not going to help your problem.

[Bassmickeyd]

I'm in Toronto and at one time I owned a Fernandez jazz bass with a neck that would not straighten in my climate. I sent it back to California and it worked fine so the guy sent me another neck that worked great..... Go figure. ..... Glad you're trying it yourself. ..... Have you tried a shim in the heal of the neck pocket? ...... I realize that won't fix the neck problem but will it might let you know what the real problem is. Personally many of these necks are made from wood that hasn't been tried correctly. .... But what can we expect at the cost of todays instruments. .... In Europe nobody will buy an instrument under $3,000 we're just spoiled.
Though I'm not sure why the truss would be corroded?

[Tusec]

Well, if you were able to thread a bolt 1/2" into the truss rod nut, then the threads in the nut must be clear for 1/2". Given this, and given that the rod has 1/4" of length sticking out from the hole, and assuming that once the nut is finger tight (i.e once it's threaded onto the protruding rod until it's just seated) you're not threading it on another 1/4" (thereby using up all of the 1/2" of threads in the nut), then the problem has to be in the truss rod's threads. And if that's the case then it's probably the threads on the section inside the hole where you can't see them. But as you tighten the nut they are pulled out of the hole and into the nut where they jam. The reason the washer would work is it would allow more tension to be put on the rod without needing to draw as much of the threaded length into the nut.

Sorry for the wordiness -- hope that made sense.

[SeismicAssault]

Originally Posted by Tusec

Well, if you were able to thread a bolt 1/2" into the truss rod nut, then the threads in the nut must be clear for 1/2". Given this, and given that the rod has 1/4" of length sticking out from the hole, and assuming that once the nut is finger tight (i.e once it's threaded onto the protruding rod until it's just seated) you're not threading it on another 1/4" (thereby using up all of the 1/2" of threads in the nut), then the problem has to be in the truss rod's threads. And if that's the case then it's probably the threads on the side inside the hole where you can't see them. But as you tighten the nut they are pulled out of the hole and into the nut and where they jam. The reason the washer would work is it would allow more tension to be put on the rod without needing to draw as much of the threaded length into the nut.

Sorry for the wordiness -- hope that made sense.

No, I gotcha. So if the threads that are inside the anchor are the problem, then just don't use them. Use the ones that are available by adding the washer. I'll see if I can dig some of those washers up.

[Tusec]

Originally Posted by SeismicAssault

No, I gotcha. So if the threads that are inside the anchor are the problem, then just don't use them. Use the ones that are available by adding the washer.

Yep, exactly.

[doktorfeelgood]

Originally Posted by SeismicAssault

No, I gotcha. So if the threads that are inside the anchor are the problem, then just don't use them. Use the ones that are available by adding the washer. I'll see if I can dig some of those washers up.

Make sure you use SOLID flat washers. No star washers or lock washers. )-(

[Thunder_Fingers]

This actually happened to the 2 geddy's I owned.. One was new and one was used, I love the bass, but I gave up on them after that.

[SeismicAssault]

Originally Posted by doktorfeelgood

Make sure you use SOLID flat washers. No star washers or lock washers. )-(

Any reason why solid's are better than lock washers?

[SeismicAssault]

So I added a washer to it, and no change.