Lumber Glossary

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AIR-DRIED LUMBER: Wood that has been dried from its freshly cut state by stacking it (usually out side) with stickers between. Air-drying reduces the moisture con tent to about 12—15 percent. Wood for interior use needs to be dried further.

BOARD FOOT: A piece of wood that is 1 thick by 12" wide by 12" long in the rough — or its cubic equivalent.

CHATTER MARK: A defect caused when the board was surfaced at the mill and the knives mar the surface.

CUPPED: A board with edges higher than its middle. The cup is always to the sap side of the board.

DEFECT: An imperfection in the board that will change how it is graded (and its price).

DIMENSIONAL LUMBER: Lumber that is surfaced on all four sides (S45) to specific thicknesses and widths: 1x4s, 2x8s, etc. Note that with this lumber the finished thickness and width are less than the stated size. For example, a 1x4 typically will measure 3/4 " X 3-1/4".

END CHECK: Separation of the wood fibers at the end of a board, almost always a result of drying.

FLITCH: A log that is sawn into veneer with the sheets stacked in the same order as they come off the log. Good for bookmatching.

GREEN LUMBER: Wood that has been freshly cut from the tree, typically with a moisture content of 60 percent or higher.

HEARTWOOD: The part of the tree between the pith (the very center) and the sapwood (the whitish outer layer of wood).

HONEYCOMB: A separation of the wood fibers inside the board during drying. It might not be evident from the face of the board.

KILN-DRYING: An artificial way to reduce the moisture content of wood using heat and forced air.

KNOT: A circular woody mass in a board that occurs where a branch or twig attached to the tree.

LINEAL FEET: A wood measurement based only on a board’s length and not its width or thickness; usually used to refer to mouldings.

MINERAL STREAK: A typically green or brown discoloration, which can be caused by an injury to the tree.

MOISTURE CONTENT: The percent age of a board’s weight that is water.

PITCH: A resinous, gummy sub stance typically found between the growth rings of softwoods.

PITH: The small and soft core of a tree that the wood grows around. It’s undesirable for woodworking.

PLAIN (FLAT) SAWN: A method of milling a log that results in the growth rings intersecting the face of the board at an angle less than 45°.

QUARTER-SAWN: A method of cutting a log at the mill that results in the growth rings intersecting the face of the board at more than 45°. Quarter-sawing wastes more wood and requires more effort. But quarter-sawn wood is more stable.

RANDOM WIDTHS & LENGTHS: While softwoods and cabinet woods such as red oak and poplar can be found as dimensional lumber, many hardwoods cannot. These hardwoods are cut in different widths and lengths to get the best grade.

RIFT-SAWN: A method of cutting a log that results in the growth rings intersecting the face of the board at an angle between 300° and 60°. More stable than plain-sawn wood; less stable than quarter- sawn.

ROUGH: A board as it comes from the sawmill; not surfaced or planed.

SLR1E: The acronym for "straight line ripped one edge," meaning the board has one true edge.

S2S: Planed on two faces; the edges are rough.

S3S: Planed on two faces and one edge; one edge is rough.

S4S: Planed to a smooth finish on all four long edges of a board.

SAPWOOD: The lighter colored wood between the heartwood and bark; typically weaker than the heartwood.

SHAKE: A split that occurs before the tree is cut, usually from the wind buffeting the tree.

SHORTS: High-quality lumber that is less than 6’ long.

SOUND KNOT: A knot that is solid across the face of the board and shows no sign of decay.

STRAIGHT-LINE RIP: A perfectly straight edge that is suitable for gluing.

SURFACE CHECK: A shallow separation of the wood fibers.

TWIST: A defect that occurs where the board has warped into a spiral.

WANE: The presence of bark on the edge or corner of a piece of wood.

WARP: A general term for a distortion in a board where it twists or curves out of shape.

WORM HOLES: A void in the wood caused by burrowing insects (killed during kiln-drying).

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This page was last modified on: Tuesday, 2007-10-30 2:29 PST