reactionary quarter sawn white oak

[jim mills]

According to the chart I have EMC for this area this time of year is 12.8%. It's been hot & humid here in the midwest. Not sure how fast wood changes MC with the weather.
Since I have several other species of wood stored here, and dont have problems, other than the occasional uncooperative board, I'm blaming it on the characteristics of QSWO, or just this batch.

[jim mills]

Thanks John. I have a busy week, but I have the oven & digital scale like you show. I'll give it a try & report back.

[Prashun Patel]

Moisture is a possible issue. However, if the parts are truly quartersawn white oak (or red for that matter) then (in my recent experience) they don't usually move so dramatically even when completely green - let alone pretty-close-to-dry, which is likely what you have. I get immediate movement from tension releasing. I suspect that's what you have going on.

Can you show some pictures? There might be something going on that you are not describing.

[Robert Engel]

Jim,

The MC # is not what's important as whether the wood is acclimated. 10-12% is pretty typical in the summer where I am. For furniture projects, I bring the wood inside a climate controlled room to get the MC down and keep the wood in there during the milling and builidng process.

Be sure to mill evenly on both sides and sticker between sessions. The key: go lightly no more than 1/32" per pass.

With any wood, once you start milling and cutting, any internal stresses are released. Air dried lumber is supposed to overcome some of that so it could just be the wood in this case.

That being said, even if this wood was perfect, 7/8" out of a 4/4 board is a bit optimistic unless its milled a very strong 4/4 or very , very straight boards.

I would cut the boards to length & sticker in a lower humidity environment for at least 1 month.

Whatever you do, don't put them in the sun!!

If not useable, I would make veneer out of the nicest boards.

[edit] I also agree with what Ed said about the grain pattern in the tree. I remember a huge sycamore (36" dia) that I thought would yield a huge amount of QS material. Well, once we got the log on the mill the sawyer pointed out how the entire log was twisted in a spiral. Needless to say, it didn't pan out too well.

[John TenEyck]

My meter is a $200 lignomat scanner type. Nothing special, but it can give me comparative readings from when I bring the wood to the shop, then when I use it. I've never really trusted the thing. Since I have had this wood so long, I haven't really been monitoring it. How can it still have a high moisture content after being stored for 5 years in a non airconditioned and only slightly heated (50 deg F.) warehouse? I think I will grab a few boards and head to the mill this week and see what they have to say.

Moisture is only an issue if your shop has a different EMC than where the wood is stored. It's especially an issue the greater the difference and how quickly you start working it after you bring it to your shop.

You said the EMC where the wood is stored is 12.8%, if I understood it correctly. What's the EMC for your shop? If both are 12.8 +/- 1% or so then the problem is not moisture related, it's internal stress as you suspected. But if the difference is 3 or 4% I'd say moisture is the problem. I resawed some maple once at 12% MC when the EMC of my shop was 8%. Big mistake. Those boards never did flatten out.

John

[Brian Holcombe]

I suspected it to be stress related due to the comments around the board moving basically as it's being milled or shortly thereafter. I milled a lot of QSWO last year and early this year for a kitchen build and I found I had to be exceptionally careful about removing even amounts, much more so than other materials such as walnut, mahogany or ash.

Quarter sawn material tends to bow as it's worked, I've noticed that to be pretty much across the spectrum with QS material. White oak simply more so, to the point where I won't resaw it unless I plan to cut into short lengths and joint again afterward

[John K Jordan]

[edit] I also agree with what Ed said about the grain pattern in the tree. I remember a huge sycamore (36" dia) that I thought would yield a huge amount of QS material. Well, once we got the log on the mill the sawyer pointed out how the entire log was twisted in a spiral. Needless to say, it didn't pan out too well.

I've had logs like that. And the sawyer can really mess up cutting a straight-grained tree. If the grain is not straight down long axis of the board but is angled to one side and/or up or down the board can twist when drying unconstrained and could develop internal stress if dried with stickers and weights, seems worse in some species than others. Unless quartersawing I try to shim up one end of a tapered log to make the best cuts as parallel as possible to that side of the tree but that's a lot of work. (If the sides are straight you can flatten one side then flip the cant and the bottom will be now be parallel but that can waste some good wood. If the log is thrown on the mill and sawn through and through you take what you get.

Internal stresses in even well dried wood can be significant. When woodturning very dry wood, say to make something with a lid that fits, it is necessary to reduce the wall thickness to close to the final dimensions then let the piece sit to let the stresses relieve themselves, then turn again. (I like to let it set overnight.) Otherwise, the thing is almost sure to go out of round, at least with some species.

JKJ

[scott vroom]

Quarter sawn material tends to bow as it's worked, I've noticed that to be pretty much across the spectrum with QS material. White oak simply more so, to the point where I won't resaw it unless I plan to cut into short lengths and joint again afterward

Hmmm...I've read that that quarter sawn wood is more dimensionally stable than plain sawn. I haven't worked extensively with QS but did an entire kitchen with QSWO about 6 years ago and I don't recall having had any of the issues discussed by the OP.

[Mark Bolton]

The 12% is the issue. Run it through a kiln cycle and you'll be fine.

[John TenEyck]

Well, yes, QS WO is a lot more stable than plain sawn, with a radial shrinkage of 5.6% vs. 10.5% tangential shrinkage. But those are still pretty high, as are all the oaks, compared to more stable species like black walnut, mahogany, etc. The reason WO is so often quarter or rift sawn has as much to do with trying to end up with something usable as aesthetics. The ratio of the tangential/radial shrinkage for the oaks is pretty bad. White oak has a ratio of 1.8, while it's 1.4 for both black walnut and mahogany. It's the difference in shrinkage that can cause lots of problems during drying and the wood to do wonky things afterwards. Most people know that beech is notorious for being very difficult to dry. It has a ratio of 2.2. So white oak isn't the worst stuff to work with but it can be difficult if it wasn't dried with care. In that regard, air drying can result in huge problems with some species, white oak being one of them, if the logs are milled during a time of rapid drying. I've ruined my share of nice green lumber learning that fact. Kiln drying can be just as bad if the kiln operator didn't follow the correct schedule for the species, cut, and/or thickness.

John

[Steve Demuth]

Quarter sawn material tends to bow as it's worked, I've noticed that to be pretty much across the spectrum with QS material. White oak simply more so, to the point where I won't resaw it unless I plan to cut into short lengths and joint again afterward

Yes, this. I've resawn QS White Oak for bent laminations, and more often than not if I take a perfectly straight board with grain like an arrow and saw a 3/32 lam off it, the remaining board will come out with a significant bow in it. I have concluded that a certain amount of differential tension across the moisture gradient is inevitable when drying quarter sawn material, and that eventual equilibration of moisture content doesn't relieve it, so as soon as you peel an significant wood off one side or the other, your board will bow. I suspect (and I have only intuition, no actual measurement) that the more rapidly the wood loses moisture, the more tension induced in the structure, so when you take the outside layer off one side, the induced tension is automatically higher on the other, and voila, a bow. The only solution I know is to take shallow cuts and alternate sides, if you're trying to create straight solid boards, and to get good at resawing curved stock if you're making veneer or lamination material.

[Scott T Smith]

Quarter sawn material tends to bow as it's worked, I've noticed that to be pretty much across the spectrum with QS material. d

Brian, I will respectfully disagree.

Quartersawn lumber - if properly milled, dried, conditioned and stored, should be extremely stable - much moreso than flatsawn material. I have literally handled hundreds of thousands of board feet of kiln dried quartersawn oak and sycamore, including performing a lot of S2S and resawing, and am extremely well versed with this process. We've even quartersawn sweet gum (a wood that has a terrible reputation for movement), with excellent results. Last month we resawed kiln dried 5/4" thick sweetgum boards into 1/2" thick panels and the material stayed dead flat after resawing.

There are certain rules that must be followed though.

The miller needs to start with clear, straight logs that do not exhibit tension (centered pith on both ends of the log), and when milling it is critical to center the pith in both directions on the sawmill. There should be minimal, if any, visible slope of grain on the edges of the boards. Pith wood should be edged off, along with most of the sapwood.

At the end of the kiln drying process, the kiln operator should condition the boards by bringing the MC% of the shell up to match the MC% of the core.

After kiln drying and conditioning, if stored in a MC% controlled environment designed to maintain the MC% around 6-7%, the boards should remain very stable when millwork is done. Post millwork, as is standard best practice the boards should be stickered so that the different sides can equalize.

If these rules are not followed then problems can arise. However the blame lies with the miller, kiln operator, storage environment or craftsperson and not with the fact that it is quartersawn.

Respectfully,

Scott Smith

[Brian Holcombe]

Thanks Scott, Very much appreciate your insights. It’s been my experience lately that runout on the side grain is near impossible to avoid. However I’ve recently sourced quarter sawn material from a very experienced operator so I will keep an eye on it and see how it behaves.

What you describe is exactly my ideal, thst is the holy grail of material I am constantly searching for. I’m glad to know that it does exist and that people such as yourself are cutting with those considerations in mind.

[Ron Citerone]

I can't speak to the tree or how it was sawed but I had this experience with WO. I brought a few boards in from outside and jointed it and it twisted and warped like crazy. I thought that it was reactionary. I let the rest (200 bd ft) acclimate in my shop for 3 or 4 months and it worked perfectly after that.........amazingly stable. I wouldn't give up the ship yet. My 2 pennies.

[Lee Schierer]

As I recall, white oak takes a long time for moisture changes to occur, something on the order of a year per inch of thickness. Moving wood from unheated storage at 12% MC will take a six months or more to reach the EMC in a controlled climate space in the center of a 1" thick board. The best way to measure moisture with the Lignomat type moisture meters is to slice off an inch or so from the end of a board and immediately measure the moisture in the center. Obviously you should do this after the board has been in the space for several weeks or more. Compare that reading to a reading taken on the outside anywhere along an edge. If the readings are the same, your board is probably at EMC.