Things To Know About Lumber

Things To Know About Lumber



so while I was setting the bulkheads in this footing I happened to notice three really good examples of three different grain orientations in these two-by-four templates this is coarse grain that is there's about four growth rings per inch that's terribly course that's rapid growing second growth Douglas fir but that's vertical grain orientation you see that the growth rings are perpendicular to the long side of the board that's vertical grain that's the most stable board that you can buy as a vertical grain board look at this next board how cool is this they just showed up this is rift sawn that is the growth rings are at approximately a 45 degree angle to both the wide face and the narrow face that's pretty good but the real improvement here is how tight that grain is can you see that that's probably eight growth rings per inch this is probably 12 growth rings per inch that's moderately fine grain Douglas fir really fine grain Douglas fir we'll get into the dozens of growth rings per inch and then this last board check this up that's classic flat saw nor slab grain and it's coarse one two yeah four growth rings per inch very coarse kind of weak compared to the tight grain but it's very classic that the growth rings are at 90 degrees to the narrow face of the board tangent more or less to a line drawn parallel to the wide side of the board so in this age of most much most of our lumber coming from second growth or third growth timber the trees are smaller in diameter and so a larger proportion of the board's have the heart in it can you see that what about there that's what the heart looks like when it's captured in the in the end of a board the heart is inherently unstable there are radial stresses around a heart see where everything's growing around it in a nice tidy circumference and then when you cut the side of that circumference open look what happens it wants to split not only does it want to split but it wants to twist around the heart you walk out onto a job site or to a lumberyard and you see a board that's twisted like the propeller on an airplane if you pick it up I will bet you I don't know what I would bet you but it would not be a small bet that every twisted board you pick up is going to have the heart in it heart center boxed heart try to avoid it if it's a board that needs to remain stable flat straight predictable for a long period of time there's about four ways that a board will move as it dries it'll bow and that is it'll take a bend in this direction with the wide face perpendicular to the bend it'll crown which is it will Bend in this direction harder for board to do that but they'll do it and that is Bend with the narrow face perpendicular to the bend it'll twist it'll rotate usually that's around a heart center and you've got cup that a board will twist particularly a wide board it'll deform it'll kind of tighten towards us the smaller circumference growth rings so when you're framing particularly but even in forming it's just a good idea to get in habit of checking for crown this board has a little bit of crown up typically you put the crown up and a floor joist or a rafter or in a stud you put the crown to the outside we're going to crown this to bay up and see how much more dirt I've got to dig out none we did

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