#1 Common: Wood characteristics – flags heavy streaks, scattered pinworm holes, tight knots, & minor working imperfections. Will admit all stains, discoloration, & black natural colors.

Backs: The reverse side to the face of the plywood panel. Generally, the poorer side of any grade plywood panel calling for a face and a back. (Grades: 1 – Species matched back, 3/8" knots, matched and mismatched veneers; 2 – Species matched back, ¾" knots, rough grain 3/16"x10 repair splits; 3 – Option species back, 1 ½" knots, unlimited small defects, 3/8"x12 repair splits.)

Bark Pocket: A small area of bark around which normal wood has grown.

Burl: A swirl or twist in the grain of wood, usually occurring near a knot, but which itself does not contain a knot.

Clear: Face shall be reasonably free of defects. Varying natural color, or faint seasoning shadows shall not be considered a defect. Will admit occasional pin knot or dark spot.

Core: The innermost portion of plywood usually composed of veneer. Also referred at as a "center." A core may also be made of fiberboard, particle board, or lumber.

Crossbar: An imperfection or irregularity in the grain of wood running at right angles to the length of the board.

Crossbanding: Inner ply veneer placed at right angles to the core, face, and back of a plywood panel.

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Defects: Anything interrupting the smooth flow of wood surface. This includes loose knots, splits, voids, wormholes, bark pockets, and others.

Delamination: The separation of the inner ply's in a panel due to the failure of the adhesive bond.

Face: Face shall be reasonably free of defects. Varying natural color, or faint seasoning shadows shall not be considered a defect. Will admit occasional pin knot or dark spot.

Face (plywood): The best side of a plywood panel in which the outer veneers are of different grades. (Grades: A – Minimal pin knots, small burls, 6" mineral streaks, book matched, 15% sapwood; B – Repairable 1/8" knots, 8" mineral streaks, 20% sapwood; C – ½" sound knots, 12" mineral streaks, 25% sapwood.)

Grain: The pattern, size and often direction of the fibers in wood or veneer.

Gum Spots: Accumulation of resinous material often found on panel surfaces. May be removed by sanding.

Half-Round Slicing: Off-center slicing cut slightly across the annular grown rings resulting in half-round, plain slice, or rotary characteristics.

Hardwood: General term referring to the wood of different deciduous trees as opposed to the softwood of evergreen or coniferous trees. Does not relate to density of wood.

Heartwood: The center portion of a tree consisting of mature wood that has stopped growing. Generally distinguishable from sapwood or the growing outer portion by its darker color.

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Knot: Circular portion of a board or veneer that was once the base of a branch or twig growing from the trunk of the tree.

Knot (Open): Opening produced when a portion of a knot has dropped out or separated due to seasoning.

Knot (Pin): Sound knots less than ¼" in diameter.

Knot (Sound): Knots that are solidly fixed by growth and retain their place in lumber or veneer.

Knothole: Opening produced when knots drop form the wood in which they were once embedded.

Lap: The over lapping of one piece of veneer on another in the same layer of ply.

Lumber Core (L/C): Sliced boards 3/4" wide and random length.

Medium Density Fiberboard (MDF): A panel or core material manufactured from pressure cooked warm fiber, resin and wax.

Mineral Streak: A discoloration of hardwood and hardwood veneer.

Particle board: A panel or core material manufactured from pressed sawmill shavings, resin and wax.

Patches: Filler material inserted into defects of veneers of panel for repairs.
Plain Sliced (P/C): Veneer sliced from a log tangent to the trees annual rings.

Ply: A single sheet of veneer forming one layer in a multi-layered piece of plywood.

Plywood, Hardwood: A panel composed of layers of inner ply's, or other core material joined with and adhesive to a face veneer of hardwood and a back veneer, usually also composed of hardwood.

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Quarter Slicing: Quartered log sliced at right angles to the growth rings.

Prime: A combination of 60% first grade & 40% second grade.

Rift Cut: Veneer cut from a quartered log on a 90 degree angle to the grain.

Rotary Cut (R/C): Veneer peeled from a whole log set in a lathe and turned against a special knife.

Sapwood: The light colored, living portion of a tree located between the heartwood and the bark.

Second: Face will admit tight, sound knots & slight imperfections, but must lay without waste. Also admits prominent discoloration, seasoning stains, dark spots & streaks.

Second & Better: A combination of first and second grades.

Select: Face may contain sapwood, and will permit occasional pinworm holes of not more than 1/16" in diameter, as well as slight imperfections and occasional small tight knots.

Select & Better: A combination of clear and select grades.

Slip Matched: Veneer sheets that are laid side by side to form a whole sheet with a repetitive grain appearance.

Splits: Separations of the wood fiber running parallel to the grain.

Veneer: Peeled or sliced thin sheets of wood used as inner ply's or as decorative faces.

Veneer Core (V/C): Laminated wood veneer crossbands.

WPF : Whole piece face.

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