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I have finally located some local sources for Locust and have bought a billet(4"x9 1/2"x6') to resaw. One question I can't seem to fully understand is why some woods are used flatsawn and some have to be quartered. I understand the concept thar it should be quartered yet I see several woods sold that are flatsawn ie. Cocobolo, E.I. and Braz. Rosewoods and Curly Maple. Apparently from research that Black Locust is one if not the most dimensionally stable american woods. So I was wondering if I could get away with using flarsawn lumber at least on the back. Also if anyone has any information on this wood that they would like to share I would appreciate it. Hard to find much about it because it really isn't a commercial available species. Lots written about fence post and boat lumber but nothing about guitars. As alot of people know it is in the Acadia family with Koa. Thanks for your help. Bill-The Greenman

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Mistakes are mandatory-learning from them is optional. http://www.opensourceluthiersupply.com

I know there were posts over the years that i read that were pretty mixed over the use of Black locust. Not sure where. I remember looking it up in a wood database because it does grow locally. I wasn't impressed with the look of it however.
Any particular reason you wanted to build with it?

I believe the reason for flatsawn is more for the wild grain aesthetics than anything else.

A guitar back is locked in by the braces and rim, thus quartersawn wood is always preferable to flat-sawn because it shrinks less dimensionally. Less risks of deformations and cracks.
I think bird's eye maple is only visible on flat-sawn stock.
It's always possible to build with a 4-piece back if your quartersawn stock is too narrow.

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Laurent Brondel
West Paris, Maine - USA
http://www.laurentbrondel.com/

I would quarter saw it if you can and still get wide enough boards for the back.It doesn't contract or expand as much as most woods so flat sawn would probably work on the back as well as the sides if you must flatsaw it.They get away with it with maple , which expands and contracts more than locust does. Locust is heavy, dense, and coarse grained which is hard to work though.It is a very stable wood.Most wood looks better when flat sawn.Quilted & birdseye are always flatsawn.Hope this helps,Mark

Bill, I'll take a stab at some of what you are asking. This can be considered somewhat as my opinions, added to wood physics. I know enough to be dangerous.

>why some woods are used flatsawn and some have to be quartered.
Several folks already mentioned that the desired figure of Birdseye Maple is best seen in very well flatsawn wood. Looks like eyes. If Birdseye is cut quartersawn, it looks kinda like curly Maple, with dark, irregular curls, and it is easy to crack apart at the elongated eyes. Quilted wood shows up looking like little pillows or the puckered areas of a quilted blanket between the seams - if the wood is cut flatsawn. If that wood is cut quartersawn, it looks like irregular waves - not as dynamic as the quilted pattern. So, that's why those wood features/figures are displayed to their best advantage by flatsawing the wood. No matter what the species is, or how beautiful it looks flatsawn, you still need to consult a chart showing the tangential shrinkage of that specific species of wood. For example, different species of Maples have different tangential shrinkage values. Secondly, you might want to take into account just how wide the back of the instrument is. I might be game to try Birdseye Maple on the back of a mandolin or uke, but there is no way I would attempt a 16" or 17" wide lower bout with that species.

Bigleaf Maple has a tangential shrinkage value of 7%, and since I know that there are guitars that have survived more than a few winters (seasonal RH changes), made of quilted (flatsawn) Bigleaf Maple, that number of 7% tangential shrinkage sorta got stuck in my head as the borderline of acceptability (of what I would use.) Even then, I would carefully think about how wide the instrument back is going to be, where the instrument is likely to live, and if the owner is going to be willing to make sure the guitar stays humidified in the dry months.

If you're wondering why so few boards of quartersawn wood are available at lumber yards, you need to visualize commercial milling from logs, and realize that the entire log is sliced "through and through", without rotating the log, yielding between one and three quartersawn (or close to quartersawn) boards, total, from the entire log.

Another answer to "why" then has to do with wood availability. If there are lots of flatsawn and rift sawn boards, and very few quartersawn boards, then the flatsawn stuff will get consideration - if it has a low enough tangential shrinkage rate. Cocobolo has a 4% tangential shrinkage rate, making it quite stable even flatsawn. Now, to my eyes, flatsawn Cocobolo is not "master grade luthier wood" and part of that comes from the fact that flatsawn wood does not exhibit a mirror match when bookmatched. I personally want at least the center seam of the back to be quartersawn, so I get a good mirror bookmatch there. If the wood falls away to rift and/or flatsawn as it approaches the extremes of the lower bouts, that's fine with me and sometimes even has more visual interest than a back perfectly quartersawn across the entire width. But still, from a stability standpoint, flatsawn Cocobolo is more stable than some other species of wood quartersawn, and it is more available, so you're going to see more of it on the market. Brazilian rosewood has such a mystical aura of supremacy as a tonewood that it makes no difference how crappy the wood is (in terms of stability or color or grain orientation) - someone will buy it.

There are a couple of "Locust" named woods from North America, Honey Locust (Gleditsia triacanthos) and Black Locust (Robinia pseudoacacia.) Both from the same family (Fabaceae), but are very different species (just in case someone has some "Locust" for sale, but is not sure what kind.) Yes, Koa is in that same Fabaceae family, but is in a completely different genus (Acacia) and the properties of Black Locust wood are really nothing like working with Koa.

Black Locust is stable (shrinkage: 5.8% tangential; 3.7% radial), really hard and dense, kind of bland looking, and being ring porous, has big pores to fill. The saving grace is that it is hard and dense and has a glassy taptone, so it should be difficult to distinguish, tonally, from something like a Brazilian Rosewood guitar, if the player is blindfolded. I believe Al Carruth has built from it, and had a favorable impression. Based on the 5.8% tangential shrinkage value (as well as the relatively close ratio between tangential and radial), I think you will be safe, in terms of stability, even using completely flatsawn material for the back of a big guitar. For my eye (that favors symmetry), I'd still look for a board that was at least close to quartersawn at one edge, and make that my back seam.

As for the guitar sides, well, I have to rely somewhat on what lots of luthiers say about flatsawn wood, because I have not bent enough sides to know this from my own experience, but generally speaking, flatsawn wood is more likely to cup or ripple when bent. So if you can't get quartersawn material for sides, pay attention to all the tricks to keep sides from rippling: use very little water, use a solid male bending form, use spring steel slats on both sides, and use bigger cauls.

Hope some of that was interesting, 'cause it was a lot more words than I thought I was going to type!

Dennis

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

Excellent post Dennis. Whew!

Wow thanks guys for the input. Special thanks to Dennis for the time and thought that went into that long post. I guess I need to jump in and see what happens. The reason I am interested is try to promote the use of local woods and to try to perserve what is left of species that are in short supply. I understand that this species has no bing like Dennis stated in a earilier post but maybe we have to learn to look at things a different way and to try to educate our customers about different priorities. I realize there is a tremendous amount of tradition here to deal with in guitar making but though experimentation we elevate the craft I think that is what interests me. I know I can build a guitar that sounds good but it is still intriguing to try to build a better mouse trap. Bill the Greenman

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Mistakes are mandatory-learning from them is optional. http://www.opensourceluthiersupply.com

Rob and Bill, glad you got something useful from the post.

Bill, I'm with you in exploring domestic species. For us in the US, that does not include very many darker colored wood species, so we need to be either flexible with old notions about what looks cool, or we need to get creative. Lighter woods framed with darker woods looks elegant to my eye, so species like Osage Orange, Black Locust, Honey Locust, Oaks, Hickories, Birch... even the Maples... look good when bound with something like one of the Walnut species. Back wedges of different or the same species as the rest of the back can add visual interest. 3-piece and 4-piece backs, either deliberate and obvious, or stealthy and subtle (like taking the waste from the waist and using those pieces to expand the lower bouts) can help us stretch narrow boards into full size guitars. Whereas the highly figured examples of any species might really clash with or look gaudy with lots of decorative elements, the "bland" wood could provide a blank canvas to really go for it, if a luthier was so inclined.

There are plenty of players right now, and I predict even a larger percentage in the near future, that will get excited about instruments made from domestic and/or local domestic species. Using the well-known tropical species may very well be more of a luthier's hangup than a player's. And, though players may be observed selecting which instrument to pick up and strum using their eyes first, once they hear how great the non-traditional wood species can sound, coming off the bench of a good luthier, they will be pleasantly surprised.

I have Claro and American Black Walnut, Myrtle, Osage Orange, Black Locust, Honey Locust, Burr (White) Oak, Mesquite, Cherry, and a couple of Maple species in my stash pile. Some are figured, some are plain, but I'm betting that every one of them can become a great guitar.

I look forward to seeing your Black Locust guitar!

Dennis

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Dennis Leahy
Duluth, MN, USA
7th Sense Multimedia

Thanks for the feedback. If I can get all this wood resawed up I will make some of it available for people to experiment with.

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Mistakes are mandatory-learning from them is optional. http://www.opensourceluthiersupply.com