DEFINITIONS

 

The grading of a hardwood plywood panel will feature a letter designation for the face grade and a number designation for the back grade. For example, a typical sheet of rotary cut white oak hardwood plywood would be A1. This panel would have an A face grade, and a #1 back grade.

The grades contained herein establish the minimum characteristics for the face and back grades of hardwood and decorative plywood produced in US and Canada. These are defined as follows:

Face Grades: Face means the better side of a plywood panel in which the outer plies are of a different grade, or either side of the panel in which the outer ply grades are identical. The face grades available include: A, B, C, D, and E.

Back Grades: Back means the side of a panel with the lower grade when the outer veneer plies are of different grades. The back grades available include 1, 2, 3, and 4.

GRADE MARKING: Hardwood plywood being graded to this system shall be identified by a grade mark on each panel, stamped on the edge, which will indicate the cut, species and grade of the hardwood plywood sheet (face and back grade). The manufacturer's name or recognized identification will appear either on the panel or on the accompanying invoice and/or shipping label.

Bark Pocket An opening between annual growth layers that contains bark. Bark pockets appear as dark streaks on radial surfaces and as rounded areas on tangential surfaces. 

 

Borer Hole: A hole caused by wood boring insects or worms.

Burl: (a) A hard woody excrescence on a tree, more or less rounded in form, usually resulting from the entwined growth of a cluster of adventitious buds. Such burls are the source of the highly figured burl veneers used for purely ornamental purposes; (b) In veneer, a localized severe distortion of the grain generally rounded in outline, usually resulting from overgrowth of dead branch stubs, varying from one to several millimeters in diameter; frequently including one or several clusters of small contiguous conical protuberances, each usually having a core or pith but no appreciable amount of end grain (in tangential view) surrounding it.

Check: A lengthwise separation of the wood running parallel to the grain.

Cross Bar: Type of figure or irregularity of grain resembling a dip in the grain running at right angles, or nearly so, to the length of the veneer.

Doze & Decay: The decomposition of the wood substance caused by the action of the wood-destroying fungi, resulting in softening, loss of strength and weight, and often a change of texture and color.

Flake: Portion of a ray as it appears on the quartered surface. Flake can be a dominant appearance feature in oak and is sometimes referred to as fleck.

Grain: The direction, size, arrangement, appearance, or quality of the fibre in wood or veneer. To have a specific meaning the term must be qualified.

Grain Sweep: Expression of the angle of the grain to the long edges of the veneer component over the area extending one-eighth of the length of the piece from the ends.

Heartwood

(heart) : The inner core of a woody stem wholly composed of nonliving cells and usually differentiated from the outer enveloping layer (sapwood) by its darker colour.

Inconspicuous : Barely detectable with the naked eye at a distance of 1.8 - 2.4 metres (6 - 8 feet).

Joint: The location at which two adherents are held together with a layer of adhesive.

Knot :The portion of the branch or limb that has been surrounded by subsequent growth of wood on the trunk or other portion of the tree.

Knot Hole: A void produced by the dropping of a knot from the wood in which it was originally embedded.

Lap: A condition in which adjacent veneers are so misplaced that one piece overlaps the other instead of making a smooth joint.

Matching :The orientation of sheets of veneer to obtain a particular pattern:

Book match :Turning alternate adjacent sheets of veneer of a flitch over so that their grain and figure form a mirror image of the adjacent piece;

Mismatch:The joining of veneer to create a sharp contrast in both grain and colour;

Pleasing match :The matching of face veneer components for a pleasing appearance;

Reverse match

(swing match) :Turning alternate adjacent sheets of veneer of a flitch end for end;

Sequence match :A method of arranging veneer faces such that each face is in order relative to its original position in the tree and, therefore, contains features of grain and figures similar to adjacent faces. Three or more such related faces are required to constitute a sequence;

Slip match: Laying adjacent sheets of veneer of a flitch without turning;

Unmatched: The random joining of veneer without regard to grain or colour.

Ply : Any single layer in the construction of a plywood panel.

Plywood: An assembly made of three or more layers of wood veneer or an assembly of wood veneer in combination with lumber core, particleboard core, hardboard, or MDF core jointed together with adhesive.

Ray Fleck See Flake

Rotary Cut : A method of manufacturing veneer in which a log or bolt is rotated against a knife and the veneer is cut in a continuous ribbon.

Rough Cut : Irregular shaped areas of generally uneven corrugation on the surface of veneer, differing from the surrounding smooth veneer and occurring as the veneer is cut by the lathe or slicer.

Sapwood: The living wood of pale color near the outside of the log.

Shake: A separation along the grain, the greater part of which occurs between the rings of annual growth.

Sliced

Flat or plain sliced: Veneer sliced parallel to the pith of the log and approximately tangent to the growth rings;

Quarter sliced: Veneer sliced in a radial direction, approximately perpendicular to the growth rings;

Rift sliced

(comb grain) : Veneer sliced at an angle of approximately 45 degrees to the growth rings to bring out certain figures, especially conspicuous in oak.

Split : A separation along the grain, forming a crack or fissure that extends through the piece from one surface to another.

Streak: Natural discolorations of the wood substance.

Mineral Streak : An olive or greenish-black or brown discoloration of undetermined cause in hardwoods, particularly hard maples, commonly associated with bird pecks and other injuries occurring in streaks usually containing accumulations of mineral matter.

Veneer :A thin sheet of wood, rotary cut, sliced or sawn from a log, bolt, or flitch.

            Color Variation example:

           

              More Terms…

Backs: The reverse side to the face of a plywood panel. Generally, the poorer side of any grade plywood panel calling for a face and a back. (Image shows "2" or "Medallion" Back.)

 

burl.gif (6873 bytes)Burl: A swirl or twist in the grain of wood, usually occurring near a knot, but which itself does not contain a knot. (See image of burl at left.)

 

Core: The innermost portion of plywood usually composed of veneer. Also referred to as a "center." A core may also be made of fiberboard, particleboard or lumber. (See image of lumber core at left.)

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

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

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

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

Face: The best side of a plywood panel in which the outer veneers are of different grades.

grnrough.jpg (2023 bytes)
Rough Grain: The pattern, size and direction of the fibers in wood or veneer. (See image of rough grain at left.)

 

gumspot.gif (7030 bytes)Gum Spots: Accumulation of resinous material often found on panel surfaces.  May be removed by sanding.  (See image of gum spots at right.)

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

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

 

Knot (Pin): Sound knots less than 1/4" in diameter. (See image of Conspicuous Pin Knot at right.)

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

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

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

minstrk.jpg (2197 bytes)Mineral Streak: A discoloration of hardwood and hardwood veneer. (See image of mineral streak at left.)

Patches: Filler material inserted into defects of veneers or panels for repair.

Plain Sliced: Veneer sliced from a log tangent to the tree's 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 plies, or other core material joined with an adhesive to a face veneer of hardwood and a back veneer, usually also composed of hardwood.

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

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

Rotary Cut: Veneer peeled from a whole log set in a lathe and turned against a special knife

sapoak.jpg (1897 bytes)Sapwood: The light colored, living portion of a tree located between the heartwood and the bark. (See image of sap in oak at left.)

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

repsplit.jpg (1973 bytes)
Splits:
Separations of the wood fiber running parallel to the grain.  (See image of repaired split at right.

   

halfknot.tif (34190 bytes)Knot: Circular portion of a board or veneer that was once the base of a branch or twig growing from the trunk of a tree. (See image of half-inch knot at left.)

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

SEE THE GRADING STANDARDS


 

Horizon Plywood.