Some will ask, “why oak?” Besides its great strength and durability, oak has features that make it ideally suited to working this way. It is a ring-porous hardwood, a term referring to the way oak trees grow. In the first part of the growing season, oak trees put on a band of nearly hollow, thin-walled pores. The second phase of growth features a layer of very tough, fibrous material, denser than the previous growth. This separation between “early wood” and “late wood” is one of the key identifying factors in these hardwoods, as opposed to timbers such as cherry and maple, in which the pores and fibers are evenly distributed. Another feature of oaks, and most other ring-porous hardwoods, is the prominence of the tree’s medullary rays. These are cells that radiate out from the pith, or center of the tree, toward the bark. Almost all the ring-porous hardwoods split or cleave cleanly and accurately along the medullary rays. This is the principal feature of the oaks that makes them well-suited for riving.
— from the forthcoming “Make a Joined Stool from a Tree,” by Jennie Alexander and Peter Follansbee
P.S. You can follow along all the posts about this book by clicking on the “Make a Joined Stool from a Tree” in the “Categories” section at right.
Ah, nothing says “I love wood” like a metal wedge that has been peened into a nice mushroom head. I have several myself, but I (perhaps naively) used them only for firewood. I am looking forward to this book more than any other. Perhaps it is the forest of oaks that surround my shop, whispering at me each time the wind blows “you need to make a green-wood stool”.
Chris,
It’s tantalising stuff.
Any news on a UK distributor so that I don’t have to keep flying across the atlantic to buy books.
St.J
I was never a lover of oak and my current project has only served to instil that opinion. Because this piece has to blend with one of my wife’s favourite pieces, I had no choice but to build it from oak, but it sure wasn’t my first choice. Pick a category other than price, and the only way to describe this species is; “not subtle”. My main complaint with it is the reason most people like oak; its grain and rays, that you speak of in your article. For me, finishing oak in the usual ways results in a grain pattern that is crass and course, all because of its extreme differences in cell structure. To get the tones closer together to produce a softer presentation, you have to add a number of additional steps to the finishing process which results in the project eating up more time and labour, something I would prefer to avoid as I am not a lover of chemicals and sanding. I have been at this current project for ten months now, and expect to be at it for another two. Once it is done, though, I will be happy if I never see another piece of oak again. Give me mahogany or give me death.
dye gives a nice even color to oak without highlighting the pores.
I’d love to work with more Oak personally, but it’s tough to find a tree to split apart round here.
However, I can get some good quartersawn oak, and do what I need. I’ve been a big fan of PF’s carving stuff, and stepped a few paces down that path so far. Oak works very well in that respect.
Most of my work is done in oak, and it’s weird to use anything else. Oak has a nice combination of tough and yet not brittle; you can get away with things in oak that in other woods would just cause them to shatter. It seems to retain that toughness even when kiln dried, although I’d like to try air dried stuff (and, for that matter, some air dried walnut and cherry) to determine how much of the brittleness I’ve noted is from the kiln drying. Oak planes readily and takes a lovely surface. Oddly I find I really don’t like the way white oak, the usual furniture wood, looks; I prefer the coloring of the red stuff.
You get used to dovetailing oak and you try to dovetail pine and it is astounding how mushy the wood is.
But mushy pine keeps your dovetailing skills sharp.
…because, it was the state tree of Maryland:
http://en.wikipedia.org/wiki/Wye_Oak
🙂
Jonathan
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I grew up in Maryland. Have loved white oak all my life. Have turned some large bowls out of WO. People are not used to seeing large bowls with dramatic rays and grain. Oh well, their loss.
Question: Wood can be quartersawn, flatsawn, etc. But I never hear the terms quarterriven, flatriven, etc. Why is this? Perhaps the most common use of riven is more or less square pices for legs and things? Please let me know. Thanks.
Eric
Eric,
Timber is riven radially, parallel to the rays and perpendicular to the grain.
Essentially all riven timber is “rift riven”.
I don’t think you could get reliable thicknesses trying to split it any other way. Riving timber perpendicular to the grain means that you can (if you’re very good at it) create even(ish) boards.
St.J
St. J.
I think you meant to say “all riven timber is quarter-riven”.
Eric
Rift sawn timber has the rings running at a diagonal to the face, between quarter and flat. Quarter sawn timber has the rings running approximately perpendicular to the face of the board.
Riven timber will be slightly wedge shaped, with rings perpendicular to the face. It is riven that way because that is the way the wood most evenly and easily splits.
Lance,
Some quarter sawn boards will have the rings running perpendicular. Some at an angle. Depends where in the quarter they were taken.
All rift sawn, or radial sawn, boards will have the rings perpendicular.
Unless I’m reading this wrongly:
http://www.aboutcivil.com/Classification%20and%20methods%20of%20sawing%20timber.html
But you’re quite right – this is the way it most easily splits.
St.John
From a timber marketing point of view, quartersawn lumber has rings that are 60-90° to the face, riftsawn lumber has rings that are 30-60°, and flatsawn lumber has rings that are 0-30°. But that’s just an industry convention, for classification (and pricing!) purposes. If you want your board to have good ray fleck figure, it has to be pretty close to 90°, closer than what the industry allows for quartersawn. Riven wood has rings that are very close to 90°, and on a freshly cleaved riven face, the ray fleck can be quite unlike what you see in a sawn board–perfectly straight and of uniform width (I wish I had taken a photo of an especially good example of that, from some riving I did last spring). That’s because the split follows all of the minor undulations of the grain. As soon as you plane the board, though, that goes away and you get the more typical ray fleck that sort of snakes its way across the board.
-Steve
I hope the lead-in picture was some kind of optical illusion, and really not a woodworker hammering in steel wedges using a steel maul, while not wearing safety glasses. Either the maul or wedges should be hard wood…! Personal safety should be a better part of this hobby or vocation than that.
I do like to work with oak. And, I do work green wood. And, yes, I do occasionally cheat on safety rules, but this is not to be encouraged. My hard maple wedges do get nicely peened over, usually just before they get put into the firewood bin.