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I am not sure if one can draw parallels from slab cut violin wood. The dimension across the lower bout of a violin is rather small, and there is no cross-grain bracing as we have on a guitar back. The violin back can shrink and swell with only the outline of the violin holding it in check.
I have been kicking around the same question regarding slab v.s. quartered maple guitar wood. Probably the best way to consider this question is to look at empirical evidence. There are thousands of maple Gibson flat tops out there and some are quite old. All the J-200s I have seen have been flatsawn curly maple and none has exhibited cracking in the maple. My sample is only about a dozen guitars, not quite enough to bank on. Perhaps other OLF members who have examined hard maple flat top guitars could weigh in with evidence of cracking.
Another instance of flatsawn wood holding up well in flat tops are the rotary-cut birch Harmony and Kay guitars. Rotary-cut wood is as flatsawn as you can get. Birch is not a particularly stable wood and all of the old American birch guitars I have seen have held up very well.

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I am certainly not a seasoned builder, but I have had a large flat cut curly maple log since 1977. I have only ever built 1 thing , a corner cabinet, from it , and that was about 10 years ago. It has held up well. The panels might occassionally shrink enough so that I can a naked line with no shellac in the very dead of winter, in my house with little to no humidification. That is a 13 inch panel perhaps moving 1/16.
I would think you could make backs safely, as long as the guitar were well cared for.
Probably most of the problem wiht flatsawn lumber is that no one has patience to let it settle down for a few years.

Flatsawn curly maple can be breathtakingly beautiful. If that is what you are looking at, I would say go for it. Hard to regret the beautiful lumber, even if does want to wiggle a little.

Filippo, I made a curly rift to flatsawn hard maple guitar in 2003 and it seems to be holding up fine, no cracks or major deformities. The curl is less pronounced on the flatsawn face. All quilted maple guitars are flatsawn, but they are usually bigleaf maple. They seem to hold up fine.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

Quilt and Birdseye figure shows best on the flat face, Flame shows best on the quarterface.

A lot of those guitars with flat maple back and sides from the factories have laminated backs and side though they may have solid tops.

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Old growth, shmold growth!

I don't think there's any difference in stability. Slab-cut won't crack any easier than quarter-cut, however, IF there is a crack, it would be easier to fix a straight crack than one that follows a crazy pattern. In Canada, 'Norman Guitars' has been making maple guitars with slab-cut maple since the early 70's (i don't remember the 60's much) and I've never heard of any problems.

Slab sawn wood is not the same as flat sawn. I have a lot of quarter sawn slabs of wood. A slab is a thick slice of wood, stone, pie, etc. The wood can be of any cut as far as grain direction and still be "slab sawn". You could have a slab sawn burl for instance.

A pretty good rule of thumb is that flat sawn will move 2X as much as quarter sawn. Hard maple the ratio is a little more than 2x.
Not a very stable wood. "Well seasoned" doesn't change the ratio to any appreciable extent.

And as TGW said the curly figure shows up in quartered boards. Birds eye more so in flat sawn boards.

L.

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Cut to size.....Beat to fit.....Paint to match.

Filippo,
I would use the wood you are considering purchasing,
but let it sit around for a while.
I've used cheap, semi quartered wood, maple,
and, it sounds great, a little too loud,
with no cracking.
So, my advise is use it, and see what happens!
Maybe i da new Padma replacement!
Wish!

I've done a few maple guitars with flat sawn local maple, none have cracked or dona anything weird. That said, I usually prefer quartered, if I can get it. On arch top mandolins, flat sawn one piece backs are pretty normal, and they hold up well, but of course that is a very different construction than a guitar.

Here's a guitar with rift sawn (?) big leaf maple, weak curl, probably a $30 BS set, but it sounds (and looks) just fine to me.

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Rian Gitar og Mandolin

I haven't made any guitars with flat sawn maple but I've made 2 banduras with it and it's been holding up just fine. I took one instrument with me to a bandura camp in the Allegheny river valley where the humidity was about 103.6% day in and day out - the back was quite wavy for that week but it mostly went away when I returned to civilization.

The wood in the pic is something I found on e-bay.

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It's a fact that flat-sawn maple is dimensionally less stable than quarter-sawn.

All personal experiences and opinions to the contrary are anecdotal.

Whether flat-sawn can be successfully used in a guitar can only be based
on probabilities. Based on the facts, there's more risk involved.

I've built with flatsawn maple many times and will continue to do so as i haven't had and problems to date building with it. And it's alot prettier to look at. The only thing i don't like about it is it likes to facet more when bent for sides, but i have always been able to sand that out at leveling time. The backs don't have any issues and look better to me. Here's one i just did. And i just love the powerful sound i got on this one.

Fillipo -

from what I read - flat sawn maple is just as stable as quarter sawn if not more when it is flat -

here's a pic of my flat sawn maple -

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It's this new idea from recent decades that everyone gets a participation award. - MUX

I built this one in 1983....from a flat sawn red maple pallet board. No problems so far. The key to using any wood successfully is to brace the back and assemble the guitar when it is as dry as it will ever be.



Most woods are more likely to crack when flat sawn, because the weakest plane is perpendicular to the growth rings. Ring-porous woods are a possible exception, but maple is diffuse-porous.
The way I look at maple is that it is a tough wood that does not crack easily.....no matter how it is sawn.

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John

John, that's a lovely guitar.
Built in the early 80's huh? Even before Ambrosia maple was cool.
Kudos for your prescience, not to mention boldness!

Steve

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From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com

That just goes to show you can't believe everything that you read. It is silly to argue this as the facts are that maple moves 2X as much in a tangential direction as in a radial direction. That quarter sawn wood is more stable in service is not a big secret or a ambiguous thing. It has been known for hundreds of years even before the science of wood technology came about.
Runamuck summed it up quite succinctly.
Whether one wants to use flat sawn wood in a guitar is another matter. Obviously lots of folks have done so without issue.



L.

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Cut to size.....Beat to fit.....Paint to match.

great looking guitar there. Love the spalting effect.

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"Preoccupation with an effect gives it power and enhances the error"
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What about bending flat sawn sides? I've never done it but would suspect it could be tricky.

John - how do you accomplish that? Do you just keep your shop dry at all times, or do you use a dehumidifier to dry it down temporarily when you are going to be bracing or assembling the box? In either case, what RH do you aim for for those steps? Thanks!

That is basically true with most woods....Spanish cedar and mahogany being notable exceptions.
There also is roughly a 2:1 ratio between the least and most stable wood species. Maple and rosewood are at the unstable end, and mahogany is near the stable end of the spectrum. But that doesn't prevent the successful construction from any of those woods.

I am fortunate to work in a very stable shop situation....where the RH normally stays between 35% and 42%.
I also heat up the wood to around 100 degrees just before installing the braces.

Sometimes it results in rippling, but I have also experienced rippling with QS sides, particularly BR.
Bending the flat sawn sides on the above guitar presented no problems.

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John

Just for the sake of lurkers who are probably reading, let's put this in plain language terms. I think Link uses the term "stable in service" very well. A chunk of maple is going to expand and contract no matter how it is sawn. Quarter sawn pieces will tend to get thicker and thinner as they move. Flat sawn pieces will tend to get wider and narrower as they move. Thus, quarter sawn pieces will be more "stable in service" for our purposes.
There's less inherent risk when building with quartered woods, but, clearly, many people have built successful guitars from woods of many species that were cut off-quarter, or even flat.

Filippo, back to your actual question: I think a person with your obvious skill and judgement will have no trouble working that maple. I might, but I doubt you will!
Patrick

I like John's maple. I have never examined any of that "ambrosia maple" up close- are those actual holes? And do you just leave them open, or bend the sides and then fill?
I do know there are a lot of buggy maples in this part of ky,- and there was a pallet company in the 80's- probably enough buggy maples in the county to supply the US. Looks real cool bookmatched.

Yes. The holes were filled with black epoxy after the sides were bent.
If you look closely, you can also see filled staple holes near the waist area of the back, and on the sides next to the neck. This was a pallet board, and I chose to match the wood color with the filler. When Taylor finally built a pallet guitar, they chose to fill the nail holes with aluminum wire to celebrate the fact that it was a pallet.







This was early in my guitar building, when I did not have a lot of money to buy 'luthier' wood. In fact, the only luthier woods in this guitar were the ebony fingerboard and bridge. The neck was cut from a timber from a local logging operation. It was too short for the full neck length, so I grafted the peghead on. I also had to add wings to the sides of the peghead.



The top is Engelmann spruce, cut from a 1 X 12 shelving board.

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John

Filippo, what exactly do you mean by" "well seasoned" luthiers"?
Would that be kin to a "pickled luthier"?
Nelson

In that case, I do meet the well-seasoned criteria