Official Luthiers Forum!

I could study the MOE (modulus of elasticity) and MOR (modulus of rupture) figures in wood property tables, consult an Ouija Board, or ask a specialist in erectile dysfunction, but thought it might be smarter to ask here:

Can soft Maples (Silver, Red, Bigleaf) be successfully used in laminated steel string guitar necks?

I know Hard Maple makes a nice stiff (if a bit heavy) laminated neck, but I wonder if any of you are successfully using Soft Maples. If yes, do you do anything special, such as only use it with carbon fiber rods, or only use it with stiffer wood(s) as the center lamination layers?

Thanks in advance for sharing your insights,

Dennis

_________________
Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

Dennis go ahead and use it. It actually isn't that soft. Nothing special needs to be done.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Dennis Walnut is commonly used in laminates, and indeed I have made whole necks of it. It is way softer than Maple.

Dennis, soft maple is only soft compared to hard maple! I've made only one acoustic neck from it and it's just fine so far...it's about a year old now...I'd say go for it!

_________________
http://www.presnallguitars.com

Thanks Bob, Russell, and Larry!

Dennis

_________________
Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

ANY maple is 'way harder than cedro, and I've made steel string necks of cedro.

The main issue with maple is that it's not as stable as mahogany, cedro or walnut. You get around that by laminating it. Make a book match with the grain vertical on the surface where you'll be gluing the fingerboard, and the curvature of the annual ring lines so that it looks like this on the end:
)))|(((,
NOT like this:
(((|)))

The proper curvature of the ring lines will help keep the joint from peeling owing to differential shrinkage. The book match will ensure that any place there is a 'wiggle' that will pull the neck to the left there will also be an equal one pulling it to the right.

Curly grain reduces the stiffness of the wood a bit. It's still 'way stiffer than it needs to be, so long as you take care of the stability.

Thanks, Alan!

I appreciate the responses from luthiers who have built necks using soft Maples, and will be more confident in using it for steel string necks.

On your second point of grain orientation within the laminate sandwich, I have a couple of questions. When you glue up neck blanks from laminations, do you aim to get a single neck from the sandwich, or two?

Seems like if you are cutting 2 necks out, then on one neck the grain lines/annular rings will converge, and on the other they will diverge.



I probably should have drawn the board with more heavily curved rings, as if it came from a smaller tree or closer to the center of a tree. The way I drew this, it may be a bit difficult to see what I mean. A well-flatsawn board 5/4 x 8+" is ripped in half, and the resulting pieces rotated 90° into position.

I have shown both the correct orientation
)))|(((, on the left
and the incorrect orientation
(((|))), on the right.


In either orientation scenario, the top guitar neck gets the aesthetically pleasing diverging growth rings (and if drawn more like typical lumber would show that much of the curved surface of the neck exhibits quartersawn wood.)

The bottom neck cut from the sandwich has converging growth rings. Most of the surface of this neck wood will exhibit rift wood. Maybe this is just aesthetics, and is simply true that the top neck in the diagram will be slightly more aesthetically pleasing (especially if the wood species shows medullary rays on quartersawn surfaces.)

Alan, evidently you are looking at the tendency of a flatsawn board to cup in the reverse direction of the annular rings, due to the different shrinkage rates of flatsawn wood (tangential shrinkage) and rift cut wood (more radial shrinkage.) I certainly agree that you don't want to be fighting against the natural physics of the wood, but I don't understand why "The proper curvature of the ring lines will help keep the joint from peeling owing to differential shrinkage." I would think that if the board contains a strongly contrasting mixture of flatsawn wood and rift to nearly quartersawn wood (and thus a strong tendency to shrink differently), that the wood would cup and the glue joints would fail regardless of the direction the boards were sandwiched. Maybe (bolstered by a sketch that does not really define the problem) I'm just not looking at the reality that the wood remaining after carving the necks does favor either cupping toward or cupping away from the glue joint, depending on the boards orientation in the sandwich. I plan to follow your advice. I would have done so before, due to the aesthetics, but will now see it as even more important for the physical properties.

Thanks for the brain food!

DennisDennisLeahy38679.0953125

_________________
Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

I go for one neck per laminate, since, as you point out, that's all you can get with the 'proper' grain.

When you do it 'right' the cupping of the wood tends to press the edges of the joint together, with the tension being in the center of the glue line. If you do it 'wrong' the glue line is in tension at the edges, and this allows it to peel apart. Glues don't usually have very good peel resistance, but are OK in tension so long as the stress is well distributed.

When I was at Sergei de Jonge's shop this past July, taking his guitar building course, he had a couple of guitars in the works with unusual neck woods, e.g. one guitar with gorgeous curly koa for the back and sides and a matching neck. Unbelievably beautiful. I love the look of a matched neck and body, and made my guitar in the course using figured black walnut for the back, sides, and neck. In my discussion with Sergei about using less stable woods (not that walnut is typically less stable, but being figured, it could be), he said that in such cases he just reinforces the neck with a couple carbon fiber rods. He actually didn't think my figured walnut neck would need that, but I put them in anyway, in part because I believe the theory that the added neck stiffness is good for the sound of the instrument. At any rate, Sergei's input on the subject bolstered my growing feeling that just about any wood I'm likely to make backs and sides out of can be used for necks as well, given carbon fiber reinforcement.

But, I'd be interested in Al's opinion, and others as well, about this - do you see the use of carbon fiber (along with a truss rod) to prevent the warping of a neck as a viable ALTERNATIVE to laminating the neck, or is it just something you might do in ADDITION to laminating the neck where stability is the concern?

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

CF limits the amount the neck can move, by adding a very stiff element. Since it's usually near the center of moment of the neck it's not as effective as it might be, but it's so stiff it still works pretty well. In a sense, then, CF notches the material up one or two rungs in the stability department. With enough CF, you could make a neck out of almost anything.

Almost...

I remember Ken Parker talking about the initial batches of 'Fly' guitars. They used redwood for the cores of the necks, with about .005" of CF built up on the outside in the form of pre-preg tape, which was then cured in an oven. Some of the necks worked fine, and others were unstable. It turns out that redwood has a split personality: sometimes it's fine and sometimes it's really unstable. When it's bad there is almost nothing you can do to make it stay put. I imagine the same is true of almost any wood: if it's unstable enough, no amount of reinforcement will keep it from moving.

In practice, I'd think that would mean avoiding any wood with obvious built-in stress problems. Redwood trees, and some hardwoods, can grow big enough to cause micro cracking compression failures in the wood at the butt, which can't be seen. However, you can sometimes see anomolies in the growth pattern that are tell tales. Reaction wood is often pretty easy to spot once you know what to look for, and I'd avoid putting any of that in a neck.