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Ever seen bird's eye maple used on an instrument? How about quilt maple? Both are flatsawn.

Flatsawn is used a lot more than anyone realizes....

Maple is one of the most stable woods around and it doesnt move much in either direction due to humidity changes or temperature changes. even flat sawn maple is a pretty safe bet.

You may get by with other flat sawn woods as well, but if they move too much from humidity, ......well, you know what will happen.

Quarter sawn wood is the most stable and moves less when cut this way, even the woods that typically move a lot. when you stray from the proven, it's a crap shoot.

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Reguards,

Ken H

Anything with true quilt figure is flatsawn - sapele, mahogany, maple, bubinga ... if you take the same board and quarter it the figure will be wavy, almost curl like.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Hi Chris,

It's probably always a good idea to consult a reference for the tangential (flatsawn) shrinkage values first, before deciding if any particular species will be stable enough to use flatsawn. Center for Wood Anatomy Research

Some woods, such as Cocobolo, are plenty stable enough to use flatsawn. That doesn't mean they'll bend the same as quartersawn, but speaks to the ability to withstand changes in relative humidity.

It takes a really huge tree to produce boards that are completely flatsawn across 8" of width. Many "flatsawn" boards will have a range from rift to flatsawn and back to rift, due to through-and-through cutting of small to medium sized logs. So, when you look of the shrinkage values, you may have to extrapolate between radial and tangential to get an idea of the shrinkage values for rift, and guesstimate the amount of rift and flatsawn wood in each board.

I was surprised when I looked up Black Cherry, that it has the exact same radial and tangential values as Bigleaf Maple (3.0% radial; 5.7% tangential.) Bigleaf Maple is the most common Maple sold as "quilted", which is flatsawn. So, put curly Cherry on your list of woods to try, and you have some latitude in grain orientation. And, you might want to use 5.7% tangential shrinkage as your cutoff point for flatsawn wood stable enough for use in lutherie.

There are plenty of species that jump above that 5.7% mark. (This might be a silly example but) Zebrawood has a tangential shrinkage of about 11% or 12% (there's an error on the site I linked to above), which means flatsawn Zebrawood wood pretty well guarantee disaster in a guitar.

Dennis

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

[QUOTE=verhoevenc] So... I'm ALWAYS wondering about flatsawn wood, cause no one ever really gives a definitive answer to whether it's an issue or not. [/QUOTE]

I thought that all there was to say about this had been said here many times. But here's your definitive answer to whether it's an issue or not: it is an issue.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

Ahh....waxing philosophical today Howard, eh? Well, you're the most qualified here to do so.

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

[QUOTE=DennisLeahy]

I was surprised when I looked up Black Cherry, that it has the exact same radial and tangential values as Bigleaf Maple (3.0% radial; 5.7% tangential.) Bigleaf Maple is the most common Maple sold as "quilted", which is flatsawn. So, put curly Cherry on your list of woods to try, and you have some latitude in grain orientation. And, you might want to use 5.7% tangential shrinkage as your cutoff point for flatsawn wood stable enough for use in lutherie.

There are plenty of species that jump above that 5.7% mark. (This might be a silly example but) Zebrawood has a tangential shrinkage of about 11% or 12% (there's an error on the site I linked to above), which means flatsawn Zebrawood wood pretty well guarantee disaster in a guitar.

Dennis[/QUOTE]

Dennis,
Please check your tables again. I believe you are looking at green to oven-dry tables. Green to oven-dry figures are useful for kiln operators so they can predict how much material they will lose in drying. Green to oven-dry figures are not terribly meaningful for end users.
The Wood Handbood, published by the USDA has a table on page 14-10 called "Coefficients of dimensional change due to shrinkage or swelling within moisture content limits of 6 to 14 percent". These figures represent what will happen to various woods in service (6-14% moisture content), once they are dried.
The soft maples are quite stable in either radial or tangential, but we see that hard maple at .00353 is on the high end of movement for domestic species in the tangential direction. So, multiply .00353 for every 1% moisture content change by the width of your piece and you get the change in dimension for tangential hard maple.
Let's take the flat sawn hard maple as an example. If the guitar dries out from 9% to 6% moisture content (that is moisture content of the wood, not relative humidity), we multiply .00353 by 3 (the change in moisture content)and then by 16 (the witdth of a guitar back). Based on these figures, the back will move over 1/8", or .169".
We mustn't forget that the back is braced and limited in the amount of shrinking a swelling it can achieve. Real world experiences as represented in the first post here are far more valuable than figures in books. I have made dozens of guitars with flatsawn Brazilian rosewood and not one has cracked. I have seen many other guitars made with vertical-grain Brazilian rosewood that have had numerous cracks and checks. As I said in my last post addressing this same issue, the skill and experience of the builder are the most important factors in a successful musical instrument.

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Stay with the happy people.
--Reynolds Large

Although I don't make many guitars, I do have an opinion that might shed some light.

In a double bass made in 1550, using pearwood that was flat sawn, the bass has survived well Here is a quote from the author Krattenmaker

"The ribs are also made of pearwood, and with an average height of 20cm, they look rather narrow for such a large bass. Their condition is fairly good. A few decades ago, they were covered on the inside with a 1,5mm thick linen as part of a restoration to keep the ribs together. The small corner blocks seem to be still original and are probably poplar". Earlier in the article he states that they are slab cut.

I am making a bass with slab cut maple and feel comfortable. But then again violin family instruments are a bit different in terms of how they expand and contract.

Anyway, that might be something of interest.

Thomas, I have to agree wholeheartedly with your assessment. I have seen a number of guitars with quartersawn rosewood backs (brazilian & cocobolo to name a couple) that have fractures in the wood. And I have seen old flatsawn wood that hasn't cracked.
It seems counter-intuitive to what we're taught regarding woods.
Normally, we think in terms of wood expanding and contracting, and we think that there's less movement when quartered. However, it would seem that in some cases, the quartsawn grain can be its weakness, because it provides a natural line of fracture for a back that is moving. A flatsawn back doesn't have those readily available straight lines for a crack to start at and follow.

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"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

[QUOTE=TRein] Dennis,
Please check your tables again.

...The Wood Handbood, published by the USDA has a table on page 14-10 called "Coefficients of dimensional change due to shrinkage or swelling within moisture content limits of 6 to 14 percent".
...[/QUOTE]
Hi TRein (Tom?),

(Warning: 14MB download if you hit the following link)
Wood Handbook - Wood as an Engineering Material by the USDA, Forest Service, Forest Products Laboratory.

(This may be a revised edition, and the info you point to is on 12-15, to 12-17.)

It would be great if there was a table that listed all of the tropical (and lesser-known) species, but this reference lists only a handful of woods imported into the US. So, at some point, we all need to look at "green to oven dry" or better 6% levels and try to make a determination of whether the species will withstand the normal seasonal fluctuations, for a given cut of lumber.

The table you point to does show Black Cherry and Bigleaf Maple to have identical movement in service, though it also gives a better idea of just how much movement that will theoretically be.

I do agree that real world experiences will sometimes contradict the scientific data laid before us. In woodworking, I'm not sure if that is faulty/false data, or the reality that every chunk of wood is indeed unique, and the testing done was not done on enough different samples from different localities.

As for cracks found in quartersawn wood, and the anecdotal evidence that flatsawn wood may be more stable, allow me to pose a question to you: if you were going to demonstrate a karate chop that breaks a board, would you prefer to try breaking a piece of 1" thick quartersawn Pine, or flatsawn Pine? In other words, perhaps the cracks you have seen in quartersawn wood tell a tale of lack of resistance to impact in service (brittleness/fragility) due to the grain orientation, rather than a dispute with shrinkage values. If so, that may be even a better argument for using non-quartersawn wood (as long as its tangential shrinkage values also fall within reasonable limits.) However, it would not be enough to persuade me, because I am a symmetry nut (flatsawn bookmatches just don't "match"), and I would want the wood as stable as possible - even if that means the instrument is somewhat delicate.

Thanks for your insights,

Dennis

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia