Guitars without trussrods

bluetrain

Hi! This might sound a bit silly question but is there any advantage soundwise if the guitar doesn't have a trussrod? On my own guitars I don't see any point in having a trussrod. I simply favour certain relief and never adjust action by adjusting the trussrod and I haven't noticed any major movement in the relief during the year together with the change in humidity.

wim

Are you talking about your Barault? Mine moves like crazy ... so I'm very glad it has the truss rod!!

Appel

Ah! A subject near and dear to my own heart. A word or two from me?

I have two guitars now without truss-rods, and I love them both. Love them. But - as I am sure is well and quickly understood - it is not simply a matter of having a guitar without a truss-rod; there is a bit more to it.

A moment's research into the history of Selmer Maccaferris reveals that (many of the?) truss-rod-free originals (at least, the 12-fret models) had necks crafted from very stiff walnut and were reinforced with aluminium plates - Selmer called them "duralumin", see p. 172ff in the Charle book, go get it off your shelf because I know you have a copy and if not why not? why not have that book? go get that book - and late-period Selmers had, of course, solid rosewood necks and were easily strong enough without any other support.

So, the type of wood is important, and the inclusion of other kinds of support is probably important as well, and perhaps even the shape of the neck is a consideration as well. If you need a thin neck, as so many contemporary players seem to prefer, it might be wise to stick guitars that feature a truss-rod.

However, there are builders who offer other options. Rodrigo Shopis out of New York offers a neck that is reinforced with (I think) carbon-fibre plates. The neck is naturally also larger than you might see on most modern takes on this design. I have a Shopis with just such a neck and it is rock-solid and trouble-free; I've taken it from very damp climates, both hot and cold, into very hot, dry climates, and back again, and the neck has not moved. Nor has the top, for what it is worth. And the guitar is light, loud, and sounds phenomenal. It's a bit stiff with Argentine 1510MF, the standard light tension 0.011-0.046 set, and I think I will try it with the 1510 standard XL 0.010-0.045 set next. Which I think will be better for the neck, anyway.

And I hear there is a pretty good builder not far from you (@bluetrain) who may also have experience in and detailed knowledge about the construction of a Selmer Maccaferri style guitar with a truss-rod-free neck. I think you know well to whom I refer. Call him up. If you haven't already.

Amir_G

Wim Glenn wrote: »

Are you talking about your Barault? Mine moves like crazy ... so I'm very glad it has the truss rod!!

Nice to know it's a common thing among Barault guitars. I also own a Barault guitar, and it definitely moves like crazy.
Barault's guitars are very lightweight - so maybe it has something to do with these radical changes. I believe that the top wood is a bit thinner than some other GJ guitars.

Buco

My guitar is built without the truss rod.
The builder uses traditional methods and he never uses the truss rod with Sel-Mac builds.
Only in my case it's a maple guitar with the spruce top, including the maple neck and the neck moves, I wish it had a truss rod or some additional reinforcement.
He did tell me that it's reinforced by some traditional methods, wood splines he said. I guess in case of maple it isn't enough because this guitar moves more than I'd like. I've seen and played his other builds which are either walnut or rosewood and the necks are straight and solid.
The sound? Who knows. It has to affect the acoustics some but it's probably negligible or at least the benefits of having adjustability outweigh some loss of acoustics.

PS since I wrote this post, I sent my guitar back to the luthier, Risto, he replaced the fingerboard which I suspect was a defective piece of wood and the neck has been very stable ever since. I don't know what kind of sourcery is he using but I have to do very little changes to adjust the action on my guitar between the seasons. I have an adjustable bridge on it now, but it's seldom used. He did tell me that he's putting wood splines in the neck, I don't have any other details.

klaatu

I also own a Rodrigo Shopis guitar without a truss rod. The walnut neck with graphite reinforcement is rock solid and does not move, even in our crazy Nova Scotia climate. Bob Holo also builds his guitars without truss rods. He sent me a typically comprehensive treatise on truss rods some years ago. I hope he won't mind if I quote it here:

Truss rods are funny things - I don't know if I'll ever use them. They don't actually do what people think they do. They are a support, but they really only determine the curvature of the neck between about the 3rd and 9th frets - they don't have anything to do with neck angle or stability as people often think. Because they're not attached along their full length, they sort of act like a really strong cable tied to the 1st fret and the 14th fret. If you tighten one, you can pull a neck into a bow - or if you loosen one that is bowing a neck you can get it to stop bowing the neck. I guess that push-pull rods can do that same thing in reverse too - but truss rods can't help with the two things necks most need... stability over the body join & help withstanding torsional pressures that come about because the tension of low strings is generally greater than tension of high strings.

Truss rods are really handy for factory guitars because the throughput is so high that occasionally you'll get neck lumber that is a little on the green side and you can't just stop production - so as it dries and shrinks relative to the ebony/rosewood fretboard it'll pull the neck into a backbow and the truss rod can fight that. (same thing happens over the body join) but the problem with fighting tension in a neck is that tension tends to find a way to express itself over the long term and that's why you see some trussrod necks piping under torsion and/or developing humps over the neck join to the body. Small shops generally have the advantage of having a low enough output to where we can make necks up ahead of time and just let them sit till they get dusty and dry because we don't have to ship a hundred guitars every Friday ... (thank god!) and so proper wood stability is less of an issue - and the carbon can then be used as purely a stability reinforcement to keep an otherwise tension-free neck in its proper position.

Now - that being said - all guitars made of wood will move with temp & humidity changes, so your neck relief will change with the seasons -so will the amount of arch in the soundboard and the combination of these two will lead to changing action season to season - but as long as it's gradual - it should be fine - just add and subtract shims to keep the action as you want it.

Bob Holo

** EDIT** Haha... I wrote this (below) before seeing that you posted, Ben. It's interesting to see what I thought a few years back and now. I started building at a time that may have been the apex of the use of the "crap rod" and was just horrified at them. Over the years I played a few old Strats & (real) Loars and thought: "Damn, I like these necks." which led me to study them and talk with a friend who is a machinist to understand alloys & tempering & metal joinery etc. It's fascinating stuff but in the end I love woodworking and so only took away the concepts of metalworking necessary to make good trussrods. Thanks for the trip down memory lane ;-)

_______________________

Here are a few things to consider when it comes to trussrods

1.) Trussrods are not for stability.
Neck stability comes from the type of wood, the cut of the wood, the quality of the wood, the stability of the wood, the size of the neck, the load on the neck, and the care/abuse of the guitar. Putting a trussrod in a neck that isn’t stable, won’t make it stable. It will, however, make the neck more resistant to abuse from heat and heavy strings, which is probably where the misconception of using trussrods for stability came from. Stability is more about hygroscopy than strength. Strength is mostly about mass and the compression strength of the wood, and long term stability / durability / resistance to damage is a function of the ability of the neck to deal with sources of abuse from heavy strings, high heat, rapid temperature changes & etc. Aliphatic and vinyl-acetate resins start to soften at around 160f and even protein glues can be damaged by this level of heat. Dried hide glue is very heat resistant on its own, but in a wood joint, at high temperatures, moisture comes out of the wood surrounding the hide-glue joint, and that moisture+heat can degrade a healthy protein glue joint. particularly in humid areas. Well, some types & modifications of protein glues, and some synthetic *-acrylate resins can hold up in heat and humidity, but are seldom used because irreversible is synonymous with unrepairable. The moral to the story, is don’t leave your guitar in your car on a sunny day, and don’t leave your guitar in direct sunlight, either outside or inside. They soak up more heat from sun than you’d ever believe possible.

Regarding neck wood stability. There is a reason that some woods are more commonly used as neck wood. Generally, the woods used for necks fit along a sliding scale of strength and stability and demonstrate a good combination of characteristics. Some commonly used neck woods are low density but have low overall shrinkage and a low ratio of radial-to-axle shrinkage, such as Spanish cedar, so they are light and not exactly strong, but very stable and appropriate for nylon/gut instruments. Some common neck woods are medium density and have moderate shrinkage and moderate radial-to-tangential shrinkage from humidity, such as Mahogany and Walnut, hence their use as general purpose neck woods. Finally, some woods have high density but higher overall shrinkage and radial-to-tangential shrinkage such as hard maple and rosewood, hence their use in bass guitars etc. Also, some woods tend to hold and express tension more or less due to their cellular makeup and where/how they’re grown. Spanish Cedar tends to be very stable. Cut 10 necks and use them all. But maple, on the other hand, runs the gamut from stable to unbelievably - jaw droppingly - comically - infuriatingly unstable. Mahogany (real mahogany) tends to be stable if cut well and Walnut is similar.

2.) Trussrods are not adjustments
This “trussrods are for adjusting playability” misconception is the corollary to the misconception that truss rods create stability. The thing is, setup geometry is a fairly static thing. If you want a guitar to play a certain way, that means a certain profile of clearance of the strings over frets that will give you a perceived string tension while you’re playing, so that your fretting and note bending are comfortable to you, and your notes ring cleanly - provided you fret and play with good technique. Truss rods are not there to allow the user to change the amount of relief or action, but rather to resist string tension to maintain the desired amount of relief put into the whole neck, not just the part affected by the trussrod, and hence maintain the setup and intonation which are adjusted through the nut, frets, bridge & tailpiece. Heavier strings might require more truss rod tension to maintain that desired setup profile. Moving to a drier or more humid climate might necessitate an adjustment of the trussrod because dry or humid wood may offer a different inherent amount of resistance to string tension, but the goal is always to use the trussrod as part of a system for resisting string tension to maintain a stable setup geometry. Loosening a truss rod to increase action will put too much relief in the neck which will change intonation and probably create a hump at the body join or a rise/drop at the other end of the fretboard depending on the design of the guitar. Also, even a moderate change in relief will change the downforce on the soundboard on a Selmer style guitar. Archtops - not so much - because their neck angle is so huge that the change is proportionately less. Think of how you put downforce on your soundboard using the strings. The downforce on the soundboard comes from strings at a tension across three points… the zero fret, the bridge top, and the tailpiece base. Raise the bridge and you increase the downforce. Raise either the tailpiece or the zero fret and you decrease it. The effect of twiddling a truss rod isn’t always disastrous, but it changes more than people realize, and it can affect the sound, playability & longevity of the instrument, which is why it’s better to make action & intonation adjustments at the nut & bridge than with the trussrod

3.) There are many kinds of trussrods, and a lot of them do nothing but introduce problems.
There are three primary mechanisms used in truss rods. There are compression/expansion rods, which compress or stretch neck wood to introduce a counter-tension to the strings. There are bending rods, such as the old Fender trussrods & late 1920’s Lloyd Loar rods, which are installed curved and straighten when tightened, because the shortest line is the straight line between points. There are self-resisting truss rods. These consist of two rods or a rod & a bar or channel that are held in a certain position by the relative tension of the two. These self-resisting rods are by far the most common today because they can, if they’re stout enough, and if they’re installed perfectly, and if the wood around them doesn’t shrink or expand thus loosening them over time, they *can* increase the stability of an unstable neck in the short term. However, they also can rattle over time as the wood expands and contracts around them over the years, and they are often a LOT heavier (heaviest I’ve seen was nearly 200 grams, vs. about 60-80 grams for a good traditional rod.

So the answer is: “It depends”. When I use trussrods, I make them, so I know the steel is top quality, the design is proper, the weight is low & the installation is proper. I use traditional rods that are a combination compression/bending much like Lloyd Loar used in the late 20’s and Leo Fender used in the early 50’s. They’re a PITA to install right, but they’re light & they lock in with the neck - they have a lot of throw and are low tension so they achieve a lot of throw and don’t over-compress & damage the neck. If done that way, there’s no difference in the acoustic performance of a good adjustable truss neck (Prewar Loar/Pre-CBS Fender) and a good fixed-truss neck (Selmer / prewar Martin) because they're essentially the same thing - a light strong reinforcement locked into and working with the neck wood as part of the neck system. But if the trussrod is a heavy rattly POS glued into an oversized channel with gooey sealer to keep it from rattling, well... all bets are off. I don't know of any good GJ builders who use crap rods though. It fairly small & harcore community of builders, like the player community, come to think of it ;-)

Jeff Moore

I have two otherwise identical Lebretons. The one with the truss sounds stronger, louder.
I'd have guessed having no truss would help sound, but who knows, it didn't this time.
These Lebretons are identical (besides neck width and depth). Back and sides are from the same piece of rosewood. I do believe he buys tops as he goes, so the tops alone (not the truss?) would more likely account for the difference.

Bones

Good point about modern necks. I've always used hard rock maple for archtops. It's pretty heavy which is a bit of a negative but very stiff and I've never had an issue with movement. Used it on about a dozen guitars. I also like to laminate at least 3 pieces and run the grain in different directions if possible.

I came across some salvage flooring that is really dense, dark, and hard mahogany that seems very stiff. I don't know what type of mahogany it is but I've selected out the flat sawn pieces for laminating and want to try it in some necks if I ever get back out to the wood shop.

Appel

@klaatu, @Bob Holo , wow, absolutely great posts. @Jeff Moore, your words about modern necks ring true for me. Thin necks are maybe for young hands that have never swung a hammer, metaphorically or otherwise ... but, as hard as swinging a hammer is on the hands, swing one enough times and you eventually get to work with a luthier who can build you a guitar neck that suits your hard-worked hands. And that is one sweet reward.

@Bones , I know this forum isn't as active as it once was but if you ever build that guitar, I'll bet whoever does look in here would love to see a picture or two ~ sounds very promising. I hope you can get to it.

Bones

I'll post some pics of maple archtop necks and one mahogany selmac neck. I've yet to finish the selmac so no clue as to the stability but hopefully someday. Been stalled by other stuff.