Part II. PRS SE fretboard removed, what to do with the recessed truss rod and the bow?

[alwinvrm]

So the fretboard is separated. The truss rod seems to be working, although I can't check the bottom thread block yet. How to solve the problem of the neck having too much bow, while the truss rod bolt is already too deeply recessed to grip and straighten the neck? Your suggestions are very welcome!!!

My idea is to A) check whether I can independently screw the rod from the bottom block to see if the truss rod hex bolt can be made to move upward and to seat the top block back in. This requires removing the truss rod and the skunk strip unfortunately. OR to remove the truss rod and put a single action truss rod, since back bow is not a problem with this neck. B) To steam/heat straighten the neck and the fretboard under tension and to glue them back together.

Below some more explanations and pics.

1) It seems that the truss rod hex bolt is already all the way in while the neck is without string tension. The neck has in that situation still a bow (like a lot of relief). So when string tension is put there is too much bow in the fret 1 to fret 8 part of the neck. in the picture you can see that there is not enough hex bolt exposed to grip and make adjustments.

2) It appears that the top thread block pushed upwards since the wood was crushed upwards.

3) Just for your info pic from the whole neck and the bottom thread block that is not visible on the neck picture.

 

[Alnus Rubra]

Subscribed because I want to know how this progresses.

 

[JasonE]

This could get interesting. I applaud you for diving into this. Hopefully you get it fixed.

 

[alwinvrm]

Some pictures for what it looks like now. The top thread is busted and PRS dealer here in The Netherlands is 99% sure that PRS don't have replacement truss rods for the SE series. So I will probably have the figure out something. I thought about putting the the rod's downer block with a a good thread up, cut of the hex bolt and put it down to make it a single action but the rod is on the short side and it will be possible but not ideal to reach the truss rod from the headstock.

 

[aamefford]

EDIT - DISREGARD MY COMMENTS ON FABRICATION. THEY MAKE NO SENSE FOR DOUBLE ACTING TRUSS RODS. I'll leave it there though, just in case it generates any ideas. Also noting that Stew Mac sells complete truss rod assemblies. Maybe you'd get lucky and one would fit?

Adjustable Truss Rods - StewMac

Shop Adjustable Truss Rods at StewMac. 100% satisfaction guaranteed. Order today with StewMAX FREE Shipping!

www.stewmac.com

I saw a nice article on truss rods here:

Guitar Truss Rod Types, Pro Tips, & How To Adjust (Ultimate Luthiers Guide)

The Ultimate Luthiers Guide To Guitar Truss Rods: Learn how a truss rod works, double-action, pro tips on how to install & how to properly adjust a truss rod.

theartoflutherie.com

Some pictures for what it looks like now. The top thread is busted and PRS dealer here in The Netherlands is 99% sure that PRS don't have replacement truss rods

I am NOT a luthier. Not by a long shot. I just retired as a shop engineer for a high precision turbo machinery shop. Faced with what you describe we would:
1) run a dye down the threads to clean them up. If we could not restore function, we would
2) order a rod of appropriate material, maybe a 300 or 400 series stainless? Ideally, a ground to size rod. Cut to length and thread both ends appropriately.

This assumes truss rods are straight? This also assumes a double acting rod is made from a single rod - I’m not sure.

I really just wanted to start the thought that fabricating a truss rod might be possible. I mean you have the fretboard off, so you are already pretty involved!

 

[Gtrbldr]

Some pictures for what it looks like now. The top thread is busted and PRS dealer here in The Netherlands is 99% sure that PRS don't have replacement truss rods for the SE series. So I will probably have the figure out something. I thought about putting the the rod's downer block with a a good thread up, cut of the hex bolt and put it down to make it a single action but the rod is on the short side and it will be possible but not ideal to reach the truss rod from the headstock.

Sucks to hear that. But, good to have a fellow dutchy on the forum!

 

[Dirty_Boogie]

I think you might have voided the warranty

Seriously, though... that takes some guts to do what you did here. I'm very impressed, and I now have a much better understanding of how a truss rod works.

 

[JasonE]

EDIT - DISREGARD MY COMMENTS ON FABRICATION. THEY MAKE NO SENSE FOR DOUBLE ACTING TRUSS RODS. I'll leave it there though, just in case it generates any ideas. Also noting that Stew Mac sells complete truss rod assemblies. Maybe you'd get lucky and one would fit?

Adjustable Truss Rods - StewMac

Shop Adjustable Truss Rods at StewMac. 100% satisfaction guaranteed. Order today with StewMAX FREE Shipping!

www.stewmac.com

I saw a nice article on truss rods here:

Guitar Truss Rod Types, Pro Tips, & How To Adjust (Ultimate Luthiers Guide)

The Ultimate Luthiers Guide To Guitar Truss Rods: Learn how a truss rod works, double-action, pro tips on how to install & how to properly adjust a truss rod.

theartoflutherie.com

I am NOT a luthier. Not by a long shot. I just retired as a shop engineer for a high precision turbo machinery shop. Faced with what you describe we would:
1) run a dye down the threads to clean them up. If we could not restore function, we would
2) order a rod of appropriate material, maybe a 300 or 400 series stainless? Ideally, a ground to size rod. Cut to length and thread both ends appropriately.

This assumes truss rods are straight? This also assumes a double acting rod is made from a single rod - I’m not sure.

I really just wanted to start the thought that fabricating a truss rod might be possible. I mean you have the fretboard off, so you are already pretty involved!

The truss rods are typically straight. It is the channel they are inserted into that are curved.

 

[deathworlder]

Something I'm not understanding...

OP has a single action truss rod. They get installed in a curved channel. They only correct forward bow; tighten only. As it is tightened, it wants to straighten out...

They also rely on the wood as part of the system. As such, the system is affected by wood density and more susceptible to movement with changes in environment.

I'm seeing this as more of a wood failure than truss rod failure. Poor or non-existent adjustability was the symptom, not the root cause.

 

[deathworlder]

You going to install a new fretboard?
I'd be worried about its stability...
In my mind, to further correct you'd need to re-level the neck, re-install the fretboard, remove frets, re-level the fretboard and re-fret.
I can't believe you were able to get it off without compromising wood under the fret slots.

 

[JasonE]

Something I'm not understanding...

OP has a single action truss rod. They get installed in a curved channel. They only correct forward bow; tighten only. As it is tightened, it wants to straighten out...

They also rely on the wood as part of the system. As such, the system is affected by wood density and more susceptible to movement with changes in environment.

I'm seeing this as more of a wood failure than truss rod failure. Poor or non-existent adjustability was the symptom, not the root cause.

Looking at the pictures again, it looks like this may actually be a dual action truss rod. That is assuming that this information on their web page is for the SE line as well as the other lines. I can't really tell if the nut at the headstock is fused or welded to the threaded rod.

https://support.prsguitars.com/hc/en-us/articles/4408303058459-PRS-Double-Acting-Truss-Rod-Adjustment#:~:text=Due%20to%20varied%20climate%20and,through%20the%201992%20production%20year.

 

[alwinvrm]

Looking at the pictures again, it looks like this may actually be a dual action truss rod. That is assuming that this information on their web page is for the SE line as well as the other lines. I can't really tell if the nut at the headstock is fused or welded to the threaded rod.

https://support.prsguitars.com/hc/en-us/articles/4408303058459-PRS-Double-Acting-Truss-Rod-Adjustment#:~:text=Due%20to%20varied%20climate%20and,through%20the%201992%20production%20year.

@deathworlder and Jason
It is a actually a dual action truss rod in the shape of a single rod truss rod, for lack of better words. the bottom nut has a normal thread while the top one has an opposite turning spiral. So the wood between the square nuts gets either contracted or pushed apart. The channel is straight . Why it is is descending towards the body we have to ask Paul Smith.

 

[deathworlder]

Looking at the pictures again, it looks like this may actually be a dual action truss rod. That is assuming that this information on their web page is for the SE line as well as the other lines. I can't really tell if the nut at the headstock is fused or welded to the threaded rod.

https://support.prsguitars.com/hc/en-us/articles/4408303058459-PRS-Double-Acting-Truss-Rod-Adjustment#:~:text=Due%20to%20varied%20climate%20and,through%20the%201992%20production%20year.

I'm wondering if that's a core spec...?

Everything I see says, plain old single action, one-way truss rod. Compression only...

IFAIK, you have to have two rods or one rod and one bar to get a double-action, two-way.
There is such an animal as a double-action, one-way...

 

[alwinvrm]

You going to install a new fretboard?
I'd be worried about its stability...
In my mind, to further correct you'd need to re-level the neck, re-install the fretboard, remove frets, re-level the fretboard and re-fret.
I can't believe you were able to get it off without compromising wood under the fret slots.

Thanx for all the tips. I releveled the neck. I was worried about the board as well. It looks good and measures okay, but I fear for these little errors that only appear when all is glued and in its final place. I had a quick look at affordable completely ready 25" fret boards in Europe but no luck. I never did a refret, so I am not really looking forward to the work and the investment in at least passable tools for the job.

 

[alwinvrm]

I'm wondering if that's a core spec...?

Everything I see says, plain old single action, one-way truss rod. Compression only...

IFAIK, you have to have two rods or one rod and one bar to get a double-action, two-way.
There is such an animal as a double-action, one-way...

Herewith the specs of a random Se guitar, c.q. SE CE 24 from the PRS site. And a copy of my comment above:

"It is a actually a dual action truss rod in the shape of a single rod truss rod, for lack of better words. the bottom nut has a normal thread while the top one has an opposite turning spiral. So the wood between the square nuts gets either contracted or pushed apart. The channel is straight . Why it is is descending towards the body we have to ask Paul Smith."

 

[deathworlder]

Double-acting doesn't necessarily mean two-way...
Might be a double-action, one-way.

If it was me, before messing with a truss rod replacement, I'd have set the truss rod at halfway(assuming loosening was an option) , popped the frets, re-leveled the fretoard and re-fretted.

 

[JasonE]

@deathworlder and Jason
It is a actually a dual action truss rod in the shape of a single rod truss rod, for lack of better words. the bottom nut has a normal thread while the top one has an opposite turning spiral. So the wood between the square nuts gets either contracted or pushed apart. The channel is straight . Why it is is descending towards the body we have to ask Paul Smith.

That is what I was thinking it was after looking at it again.

I'm wondering if that's a core spec...?

Everything I see says, plain old single action, one-way truss rod. Compression only...

IFAIK, you have to have two rods or one rod and one bar to get a double-action, two-way.
There is such an animal as a double-action, one-way...

You don't have to have two rods to have it be dual action.

 

[JasonE]

Double-acting doesn't necessarily mean two-way...
Might be a double-action, one-way.

If it was me, before messing with a truss rod replacement, I'd have set the truss rod at halfway(assuming loosening was an option) , popped the frets, re-leveled the fretoard and re-fretted.

I have never heard of a dual action one way truss rod. The fact that it moves both ways is right in the name of it. I haven't seen everything there is in this world so it may be a thing but is one I have never seen.

If you look at the pictures the OP posted, some wood broke and that affected the truss rod. It had a legit issue.

 

[deathworlder]

I have never heard of a dual action one way truss rod. The fact that it moves both ways is right in the name of it. I haven't seen everything there is in this world so it may be a thing but is one I have never seen.

If you look at the pictures the OP posted, some wood broke and that affected the truss rod. It had a legit issue.

They're out there...often times, double
-action and two-way get convoluted.

Off the top of my head, the Warmoth double action truss rod is one-way...

 

[alwinvrm]

They're out there...often times, double
-action and two-way get convoluted.

Off the top of my head, the Warmoth double action truss rod is one-way...

1) I explained in my posts of March 15 that in a PRS SE it is a single rod dual action truss rod by way of 2 counteracting nuts and an unthreaded hex nut to turn the rod.

2) Yes it is a feature on SE guitars as well as core.

3) Yes double rod single action exists, and yes single rod dual action also exists as we saw under 1), but AFAIK PRS is the only one using it.