truss rod placement

[jlarsonguitars]

I am looking to get your opinions on where to place the end of the truss rod (sound hole vs. headstock).  

John

[Dick Fulco]

Hi,

I have always placed the adjustable end towards the soundhole.

Just for cosmetic reasons.

So, I have no opinion about technical pros and cons.

Met vriendelijke groet, Dick

Op wo 13 aug 2025 om 17:22 schreef jlarsonguitars <jlarson...@gmail.com>

I am looking to get your opinions on where to place the end of the truss rod (sound hole vs. headstock).  

John

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[Paul McEvoy]

Headstock, definitely.  For me guitars it's the only way but I hate heel adjustment regardless.  

It's a challenge to make it look nice, certainly.  

Paul McEvoy
207-699-9526

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[Charles Tauber]

What I prefer is to have the truss rod adjustable from the soundhole, PROVIDED it is easily accessible and one doesn't need to use some crazy-shaped tool to access it while balancing on one's left foot and juggling four balls with one's right hand. I drill a hole in the upper transverse brace. I have the heel block extend against the top to support the fingerboard and the truss rod: the heel block ends abutting the transverse brace. The adjustment end of the truss rod can either pass through the hole in the brace or stop at the brace. It can be adjusted without removing the strings, usually, and requires no special tools. Although I've never had one break/mis-function,  with this arrangement, if one had to replace the rod, it would be major surgery. 

If one has the truss rod adjustable from the head, one removes material from a critical structural juncture of neck and head. If one removes too much material, the head is easily broken at that juncture. One can add back some of the removed material by adding a "volute" to the back of the head/neck juncture, though It isn't my preferred aesthetic. Usually, the slot/cutaway to access the truss rod adjustment is covered with a plastic or wooden plate. That, too, is not my preferred aesthetic. One potential advantage to a rod adjustable at the head is ease of access: remove the screws/plate hiding the access and make the adjustment. Another potential advantage, depending upon rod and neck design, is that, should one need to, one could potentially replace the rod without having to dismantle the instrument.  

Most truss rod designs have a block of some sort against which an adjustment nut presses. The block is usually larger than the adjustment nut and the rod(s), itself. Accommodating the added size of the block at the thinnest part of the neck - in the nut area - can result in a weak area in the neck. I've seen a few guitars where adjustment of the rod, which pushes against the bottom of the rod's slot in the neck, has forced the rod/block through the backside of the neck.  

Your chosen method of attaching the neck to the body can have implications on placement of the truss rod adjustment. Neck attachment designs fall into three general categories. The first is those that have the neck an integral part of the body/end block, typical of "Spanish" construction. In this case the neck is already "attached" to the body, the truss rod installed and then the fingerboard installed on top of that. The truss rod is laid into a slot in the neck that either extends to the head - for rod adjustment at the head - or extends into the guitar top/heel block area- for rod adjustment at the body/soundhole. 

The second design involves an attachment between the neck and the body with a fingerboard that cantilevers from the neck beyond the juncture of neck to body. The fretboard extension, when the neck is assembled, is glued directly to the outside surface of the guitar top. In this case, if the truss rod is to be adjusted from the soundhole, the truss rod/adjustment will also be cantilevered from the neck/body juncture, beneath the cantilevered fingerboard. The truss rod slot in the neck, the alignment of the neck/body joint and the slot in the body through the guitar top all need to be in alignment to allow the neck, with its embedded truss rod, to be assembled to the body. (The neck attachment method can be bolted butt joint, mortise and tenon, dovetail, etc.)

The third design involves a neck that is attached to the body but the fingerboard is not cantilevered from the neck. Instead, the neck, itself, extends beyond the neck/body juncture so as to fully support the fingerboard for all of, or nearly all of, its length. Examples of this include Taylor guitars, archtop jazz guitars and guitars with user-adjusted neck angles. In this case, if the truss rod adjustment is from the soundhole, the end of the rod will pivot as the neck angle is changed, as in the case of Taylor guitars with their replaceable shims, or the user-adjusted neck angle designs. For that arrangement, a hole through the transverse brace wouldn't work: the hole is in a static position while the end of the rod pivots. In the case of a typical archtop guitar, there isn't really room in the neck extension sitting above the guitar top to accommodate the end of the truss rod and its adjustment: unless one radically changes the design, adjustment of the rod is only viable from the head.  

Since there are many guitars that have rods adjusted at the head and many that have rods adjusted at the soundhole, both designs can work well. You choose which you prefer and incorporate design decisions that support that choice. 

Charles

[Michael Hudkins]

I can't say this with authority, but the truss rod through the headstock removes material at a stress point that might weaken the headstock and make it more likely to break in an unfortunate accident.  It does have its conveniences though.  Possibly building the guitars with a volute might mitigate any weakening.  Again, I do NOT speak with any authority on this.  It is just thinking outloud.  

On Wed, Aug 13, 2025 at 11:22 AM jlarsonguitars <jlarson...@gmail.com> wrote:

I am looking to get your opinions on where to place the end of the truss rod (sound hole vs. headstock).  

John

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[Doug Shaker]

I just don't like the look of truss rod covers on the headstock.  It's an aesthetic preference,

not a judgement on the structural integrity of the decision.

Not all my guitars have truss rods; some have graphite installed in the neck, instead.  

The guitars that do have truss rods are adjustable through the soundhole.  

The upper transverse brace has a hole in it for the required allen wrench.

I write on the upper transverse brace, so it can be read from the soundhole, the

size of the allen wrench required, and I supply a ball-end allen wrench of the correct size in the

guitar case.

Doug Shaker

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