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View Full Version : Differences between flat, quarter and rift sawn lumber



Matt Clara
09-29-2009, 05:46 AM
Ron's illustrations (http://www.ukuleleunderground.com/forum/showpost.php?p=218010&postcount=24) are excellent educational tools clearly showing the physical differences between the three types of lumber "cuts" available, quarter, flat and rift sawn. Yesterday Chuck mentioned that anything but quarter sawn wood (http://ukuleleunderground.com/forum/showthread.php?t=19570) is less than ideal for ukulele / guitar / (stringed instrument) construction because quarter sawn shrinks the least. I was wondering if anyone else could offer info on the use of the different types of cuts. Also, what happens when a glued back/top shrinks? Is that how cracks develop in the older ukes we see available? Seems you can't find an old Martin without some crack in it somewhere.

Bradford
09-29-2009, 07:13 AM
It isn't so much that quartersawn wood shrinks the least, as it is the most dimensionally stable. A quartersawn board, for example, will remain flat as it dries, where a flatsawn board will cup or warp. One of the reasons to build a slight arch in the tops and backs of instruments is to allow for some shrinkage without cracking. That said, I and others use rift sawn wood for the backs of our carved top instruments. It imparts a different sound as it tends to be a bit more flexible.

Brad

vahn
09-29-2009, 07:22 AM
hmm by that diagram it looks as if that center board of even a flat (plain) sawn wood is just as good as the center cuts of quartersawn wood.

Moore Bettah Ukuleles
09-29-2009, 07:33 AM
It's not only because quarter sawn shrinks less across its' width but it is also stronger.
In instrument building, for the same amount of mass, a quarter sawn board will be much stiffer than a flat sawn board. The things to look for in choosing and preparing wood for instruments is stiffness, weight, and mass as well as grain orientation. This is especially important when choosing bracing wood when you have so little material to begin with. I even go as far as hand splitting my spruce brace wood to ensure the grain is all running true.
Also, if it's not well quarter sawn you'll run into aesthetic problems when you try to book match. It just doesn't match up well.

Moore Bettah Ukuleles
09-29-2009, 07:39 AM
hmm by that diagram it looks as if that center board of even a flat (plain) sawn wood is just as good as the center cuts of quartersawn wood.
Yep, and that one board is the choicest cut of that log. There's a name for that particular slab that extends the width of the log. I forget what it is, Ron would know. In the plain sawn cut, it will include all the types of cuts mentioned, flat, rift, QS, and everything in between. It also yields the least amount of QS lumber

thistle3585
09-29-2009, 10:56 AM
It's not only because quater sawn shrinks less across its' width but it is also stronger. A quarter sawn board laid horizontally is FOUR times stronger than a flat sawn board of the same dimesions laid horizontally. Carpenters know this when they are laying floor joists and roof beams.
In instrument building, for the same amount of mass, a quarter sawn board will be much stiffer than a flat sawn board. The things to look for in choosing and preparing wood for instruments is stiffness, weight, and mass. This is especially important when choosing bracing wood when you have so little material to begin with. I even go as far as hand splitting my spruce brace wood to ensure the grain is all running true.
Also, if it's not well quarter sawn you'll run into aesthetic problems when you try to book match. It just doesn't match up well.

Please support that statement that quartersawn wood is stiffer and four times more stronger than flatsawn. Quartersawn is dimensionally more stable, hence its use in construction but I wouldn't say that it is stiffer. I believe it was Rick Turner that did some deflection tests where he took a 1/2"x1/2"x24" piece of quartersawn wood clamped four inches of it to a table then put a weight on one end and measured the deflection then rotated it 90 degrees so it was flatsawn and repeated the test and found the quartersawn to deflect more than the flatsawn. I believe Frank Ford also reached the same conclusion. As I understand it, the USDA has found the same conclusion in testing.

True; flatsawn lumber will expand and contract along its width but quartersawn will expand and contract along its height. And yes, carpenters do know this when laying floors because most radiant floor heating systems have specific installation instructions to account for these difference in expansion and contraction based on how the wood is cut.

I do think that you will find different attributes to "sheet" material like tops and backs as opposed to "dimensional" lumber. I would guess that grain count and run out would play a role in stiffness too.

Don't get me wrong, I am far from an expert in these matters, and I once echoed the same statements about quartersawn lumber but have been challenged by several others and was proved wrong.

Moore Bettah Ukuleles
09-29-2009, 11:15 AM
Hah! You got me. You are absolutely correct. Thank you for the correction. I was putting those thoughts together while trying to listen to the tsunami warnings we were getting here as a result of the 8.3 earthquake in Samoa. News of it was coming in at the same time I was writing my response. In my haste to get it all down I mispoke. I was also going to make the point about height and width and it's relationship to strength, but my thoughts were jumbled. Rick Turners test supports the point I was trying to make re QS vs, flat sawn; certainly flat sawn wood will deflect more than QS. I always re read my postings before I post them but this time I neglected to do so. I should go back and re correct the previous post.
BTW, the tsunami warning has just been cancelled. No fish for dinner tonight.

Lori
09-29-2009, 12:34 PM
Hah! You got me. You are absolutely correct. Thank you for the correction. I was putting those thoughts together while trying to listen to the tsunami warnings we were getting here as a result of the 8.3 earthquake in Samoa. News of it was coming in at the same time I was writing my response. In my haste to get it all down I mispoke. I was also going to make the point about height and width and it's relationship to strength, but my thoughts were jumbled. Rick Turners test supports the point I was trying to make re QS vs, flat sawn; certainly flat sawn wood will deflect more than QS. I always re read my postings before I post them but this time I neglected to do so. I should go back and re correct the previous post.
BTW, the tsunami warning has just been cancelled. No fish for dinner tonight.

Glad to hear about the tsunami warning lifting! We are flying to Maui tomorrow. Will the fish be disturbed for long? I hope to snorkel a little!

I love these threads about the many aspects that make a ukulele good or bad. Very informative, even for those of us who just buy and play.

–Lori

Moore Bettah Ukuleles
09-29-2009, 12:57 PM
A wave apparently was generated but I don't think we're going to see much of anything. If we were going to see an effect it wouldn't be for another hour from now. I'll take a break then and walk down to the coast to see if I can see anything. Your snorkeling should be fine. Have a good trip.

koalohapaul
09-29-2009, 08:34 PM
Glad to hear you're okay, Chuck. I heard the warning late in the afternoon. There was no traffic at all today, when I went to pick up my wife in Waikiki. It usually takes at least 30 minutes to get there from Kalihi. I got there in less than 15. I guess everyone went home, preparing for the worst.

Matt Clara
09-30-2009, 03:00 AM
Less than 24 hours later, this is the #8 return for a google search for "difference between quarter sawn and rift sawn wood". Yes, I am a nerd.

nic579
09-30-2009, 09:07 AM
I think the difference you will find is that rift sawn wood may still have a tendency to warp to one direction where quarter sawn should in most cases not warp to one direction or the other. ie: cupping of the with of the plank.

Pete Howlett
09-30-2009, 09:47 AM
I just got some planks of 20" wide Brazilian Mahogany, flat sawn, 25 years old. Very little cupping or bowing. Wood is organic. There are some very basic rules about it's effective use in instrument making but there are always exceptions...

RonS
09-30-2009, 12:11 PM
I seen some beautifully figured backs like quilted maple or waterfall bubinga on instruments.

The only way to cut a log to get that wonderful figure is to flat saw the wood.

So a compromise is made, stability and tone over beauty.

Is this wrong? As long as the owner likes it, I don't think so.


True; flatsawn lumber will expand and contract along its width but quartersawn will expand and contract along its height.

Quartersawn expands on the thickness, not the length or width ( not enough to worry about anyway)


I just got some planks of 20" wide Brazilian Mahogany, flat sawn, 25 years old. Very little cupping or bowing.

Did you ever hear about the Quilted Honduran Mahogany log that has been called "The Tree"? I just heard that a single guitar set recently sold for $3000. Why so expensive? The quilted figure shows up when quartersawn.

Pete Howlett
09-30-2009, 01:00 PM
And yet I love to see plain wood also - it has an inner and quiet beauty.

vahn
09-30-2009, 02:17 PM
Did you ever hear about the Quilted Honduran Mahogany log that has been called "The Tree"? I just heard that a single guitar set recently sold for $3000. Why so expensive? The quilted figure shows up when quartersawn.

Awesome awesome story... Heres a good telling:

https://mcphersonguitars.com/data/mcphersonguitars/file/321_5551_Quilted%20Mahogany.pdf