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I’m thinking about laminated necks on acoustic guitars. By that, I’m referring to 3 or more strips of wood laminated lengthwise. For this discussion, let’s not consider a scarf jointed head or stacked heel to be a ‘laminated’ neck.

I know if you search the web you’ll find people stating that laminated necks are stronger, stiffer, less prone to unwanted movement, and/or that they provide increased sustain over non-laminated necks. Such statements are usually made as if they are proven facts...but of course no proof is ever offered. I’ve never actually seen results from any study that conclusively proved that a laminated neck either was or was not any of that. Wondering if anybody else has.

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Andy
www.bounsallguitarworks.com

You're a skeptic Andy? What about the ones who claim that you can bend tone color by the wood species choice, and the thicknesses of each layer? I'd have a hard time believing that; but a laminated neck SEEMS like it could be at least as strong as a one piece neck.

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Why be normal?

There can be exceptions, but almost by default, laminated structures are stronger than solid. Laminated wooden skis and tennis rackets demonstrate this generally accepted rule. A laminate interrupts grain irregularities and weak planes.

A 3-piece neck may not make a significant difference in strength, but it should be a positive difference, in theory.

It makes sense to me that a laminated neck would be stronger then a non laminated one. Ideally you would want the center laminate to have different grain orientation then the outer two. At least, that's the way they do it with plywood. But for all practical purposes even if a lam neck is stiffer for the average string tension of a guitar it probably doesn't matter. Hundreds of years of history shows that to be the case. Lam necks will have their own problems too. They might solve one but then introduce another liek for example if the guitar goes through a massive heating event.

Coming from a banjo background, I really like the looks of laminated necks and lots of veneer under the fingerboard, peghead and backstrap. I do think that it all adds up to more stability in the neck--there are plenty of old banjo necks that are still nice and straight after a hundred years or so.

That said, on guitars I tend to stick closer to the guitar tradition of fewer, if any laminates. I really don't know why that is.

Dave

I've built several laminated necks, mainly Maple/Ebony veneer/Hog and Wenge/Spanish Cedar.
I like the look, and of course a central strip of some hardwood makes the neck stiffer if only because it has a higher modulus of elasticity than the outer wood.
When making them, the outer laminations can by reversed if not perfectly quarter sawn to "balance" the grain structure, implying a more stable structure.
So I believe can you build stiffer and more stable necks by laminating them.
As the the effect of laminations of the sound of a guitar, frequency of the neck - stiffer will produce a higher neck frequency, but what effect this has on the overall sound seems to be disputed as it is a high frequency compared to the body main frequency according to A. Carruth has posted regarding this.
As to sustain, adding stiffness and weight to the neck would seem, at least intuitively, to increase sustain, but I don't know any studies to prove this, and sustain differences between guitars can be down to other factors.
Weight increase alone can of course be simulated on the same guitar by clamping a weight to the headstock e.g. 2 x G7 performance capos weigh about 4 oz.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

In boatbuilding interior work, it is common to rip a longer piece - say a door frame - in half and flip one piece and re-glue. This is not for strength, but for stability in a marine environment. I think that a neck laminated from the same wood would be the same as this - no stronger but potentially more stable depending on the thought put into how the pieces come together.

Adding a harder/stronger wood strip int he center would change that - Martin used to use an ebony piece for a truss rod. And some luthiers will laminate a harder wood into their braces.

And having built boats and windsor chairs, bent pieces of wood are comparable in strength to laminated pieces, depending of course on the quality of the original piece. It is certainly much easier to achieve good grain orientation over a wider piece, say a guitar side, if it is laminated, but if that piece were perfect to start with I don't think there would be a strength difference

YMMV

Ed M

IMHO, lamination with parallel grain adds very little, if any strength. The comparison with water skis or tennis racquets is not applicable, because those are bent laminations where the grain follows the curved shape. While it is possible to do bent laminations on a guitar neck, it is seldom done, except when using a backstrap overlay on the peghead.
Stiffness can be added by using stiffer woods for some of the laminations, but the stiffness increase will be limited to the sum of the stiffness of each lamination. In addition, stiffer woods are almost always denser, so the neck will be heavier. You can align the grain in center laminations parallel to the peghead face to increase the strength against peghead breaks, but that will slightly reduce stiffness of the neck shaft.
Mirroring the grain angle on the outer laminations does produce a pleasing aesthetic, but IMHO it is not nearly as important for stability as using well seasoned straight-grained wood.

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John

Am I a skeptic? Well yeah, maybe.

I’m kind of thinking similarly to John Arnold above. A couple of things that I’ve been thinking...

I’ve read a number of times on different topics where folks express concern about glue creep. Is that not a potential for trouble on a laminated neck that has multiple glue joints with wood that’s under tension?

People talk about laminating different species together and having the grain of the laminations oriented in different directions claiming that this’ll make the neck more stable. Different species and different grain orientations would expand/contract at different rates in reaction to changes in temperature or humidity. So wouldn’t that tend to make a laminated neck less stable?

People claim a laminated neck increases sustain. At the same time, there’s a fellow who builds solid body electric guitars, neck and all, from a single piece of wood and he claims that the one piece guitar has maximum sustain.

So all this leads me to wonder what the truth actually is and if there is any hard evidence to prove or disprove any of these claims. Or, and I mean no disrespect, is it all really just the result of marketing hype created by folks trying to differentiate their product from that of others?

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Andy
www.bounsallguitarworks.com

Strength is probably much less of an issue in a neck than stability and stiffness. Even soft woods can withstand working loads on the order of 3000 psi in direct compression or tension. Necks don't break under the string load until they bend up, and I've only ever heard of one that actually did that; it was fir plywood, and with the laminates 'stacked'.

I like to make laminated necks with the grain 'book matched' across the center line. I would expect that to add stability, but in practice the difference may not be enough to worry about if the wood is well seasoned and stable. It looks nice, anyway. Be aware, though, the curly wood has lower long grain stiffness than straight grained, due to all of the run out, and design your reinforcements accordingly.