Washers under the truss rod nut… question

[Square]

Hey all

I have a question. I recently picked up a Fender American Vintage P bass. When I got it the TR worked freely in either direction, but was maxed out as far as tightening.

It is the vintage (heel) location and the adjustment nut was sunk into the neck about 4mm.

I had some 1/2 mm thick washers so I stacked 6 of them (3mm) and got the adjustment range I needed to bring the relief into spec, about .010.

The question is for those that have done this. What might the future look like? I’m guessing wood compression was the culprit and on a 30 year old bass, I get it. I’m just wondering how well this repair typically holds up long term.

Thnx

 

[Bruce Johnson]

Hey all

I have a question. I recently picked up a Fender American Vintage P bass. When I got it the TR worked freely in either direction, but was maxed out as far as tightening.

It is the vintage (heel) location and the adjustment nut was sunk into the neck about 4mm.

I had some 1/2 mm thick washers so I stacked 6 of them (3mm) and got the adjustment range I needed to bring the relief into spec, about .010.

The question is for those that have done this. What might the future look like? I’m guessing wood compression was the culprit and on a 30 year old bass, I get it. I’m just wondering how well this repair typically holds up long term.

Thnx

Well, you have to back up a bit. The real problem is that the neck has warped; it has bowed forward over the years beyond what the truss rod could handle. A previous owner overtightened the truss rod, trying to straighten it, which resulted in the truss rod getting crushed in enough that it ran out of threads and maxed out.

You added the washers which gave the truss rod some more range, and you were able to tighten it some more than it could before. Which was apparently enough to bring the neck into the right relief range.

The questions are:

Has the neck finished warping? Yes, at 30 years, it's probably finished bowing forward, due to internal stresses in the board. But, if the bending is happening around the 12th fret (the infamous Ski Jump) that may continue on indefinitely.

Will the internal wood keep crushing behind the truss rod? Maybe, but if it's held that position for a month or so now, then probably not.

 

[Square]

Well, you have to back up a bit. The real problem is that the neck has warped; it has bowed forward over the years beyond what the truss rod could handle. A previous owner overtightened the truss rod, trying to straighten it, which resulted in the truss rod getting crushed in enough that it ran out of threads and maxed out.

You added the washers which gave the truss rod some more range, and you were able to tighten it some more than it could before. Which was apparently enough to bring the neck into the right relief range.

The questions are:

Has the neck finished warping? Yes, at 30 years, it's probably finished bowing forward, due to internal stresses in the board. But, if the bending is happening around the 12th fret (the infamous Ski Jump) that may continue on indefinitely.

Will the internal wood keep crushing behind the truss rod? Maybe, but if it's held that position for a month or so now, then probably not.

Interesting thoughts. I can offer two things on these points.

When the neck is unstrung and the truss rod tension has been released, the neck/fingerboard is relatively flat. Using a notched straight edge to check this BTW.

There is no indication of a ski jump.

 

[Bruce Johnson]

Interesting thoughts. I can offer two things on these points.

When the neck is unstrung and the truss rod tension has been released, the neck/fingerboard is relatively flat. Using a notched straight edge to check this BTW.

There is no indication of a ski jump.

That's fairly typical for Fender necks. They are fairly soft; that is, the string tension will bend the neck a noticeable amount.

If there's no Ski Jump, that's good. It will probably stay reasonably stable for another 30 years. If it does move, that means the crushing is continuing. You could add a few more washers to get a few more years out of it. Or send it out for heat straightening. If that doesn't do it, then it'll need surgery for a new truss rod.

 

[Square]

It’s been stable for a few months so I’m hoping for the best. Just curious about the long term outlook.

Thnx

 

[96tbird]

Nothing is guaranteed, but 30 years of “seasoning” is an advantage. As for the washers, give more space AND an improved bearing surface. When the nut is just sitting on wood and you turn it, the ends of the fibres not only take the pressure of the neck, they get pushed sideways and shear off/crush. Having a metal washer as a bearing surface is better than stock since it eliminates the shearing action of the rotating nut.