Specification

18 columbiaforestproducts.com Hardwood Plywood Grading Guide 2015
Annual ring (Annular Ring): See
Growth Ring
Back: Generally a lower grade
veneer than that of the opposing side
of the same panel when a higher
grade face is specied.
Barber pole: A phenomenon in a
book matched face wherein adjacent
components appear alternately dark
and light due to the presence of
lathe checks on the loose side of the
veneer refracting light and absorbing
slightly more nishing material.
Bark Pocket: An area of bark sur-
rounded by wood of normal growth
and color.
Blending:
Color change that is
detectable at a distance of 6 to 8 feet
but which does not detract from the
overall appearance of the panel.
Book match: Veneer sheets consist-
ing of individual components that are
spliced side by side with every other
side turned over, creating a mirror im-
age at the joint due to the orientation
of the grain coming together at the
joints. The more common method of
splicing face veneers.
Burl: A swirl or twist in the grain of
wood, usually occurring near a knot,
but which itself does not contain a
knot. Clusters of small pin knots
resulting from the development of
adventitious buds or branches may or
may not be present.
Check: Any fracture of a veneer
surface along the grain generally re-
sulting from stresses due to un-even
shrinkage during seasoning or ac-
climatization, often exacerbated when
extreme conditions of exterior cold
and interior heat and relative humidity
occur simultaneously.
Checking: The appearance of
checks as described above anywhere
on a veneer face. Concentration
may be isolated to small areas or
widely dispersed over the entire panel
surface. Often associated with maple
due to the stresses inherent in that
genus.
Core: Any substrate upon which a
decorative wood veneer face and
or back may be applied by some
means of adhesion. A core may be
fabricated from hardwood or softwood
veneers of various thicknesses (VC),
or as engineered wood produced
utilizing wood bers (Medium Density
Fiberboard – MDF) or wood chips
and smaller particles (Particle Board
Core – PBC)
Core void: The absence of core
material in any component in an inner
ply of a veneer core panel as a result
of a split, knot hole, damage, or gap
between components within a given
ply. Generally of more concern when
the void occurs directly under the
decorative face veneer. Limited in the
product standard in Table 7, Summary
Of Allowable Openings For Inner Ply
Grades For Veneer Core Hardwood
Plywood.
Cross bar:
Any isolated deviation or
concentration of normal grain direc-
tion on the surface of a hardwood
or decorative softwood face or back
veneer usually occurring at approxi-
mate right angles to the normal grain
direction.
Cross band: A component ply in a
veneer core hardwood plywood panel
with a grain orientation at an approxi-
mate right angle to that of the face,
back, and any other inner plies within
the core of the panel. Also used to
infer the inner ply in a veneer core
panel occurring directly adjacent to
the face and back of a given panel.
Cross checking: A phenomenon
primarily associated with red oak but
occasionally with other ring porous
hardwoods wherein the early growth
regions exhibit small fractures across
the grain as a result of expansion or
contraction of the substrate in reac-
tion to moisture movement.
Defect: Any manufacturing mark
or damage that interferes with the
aesthetic appearance or usability of
a given panel. Types of defects in-
clude delamination, machine or han-
dling damage, dents or impressions
(press fault) in a face or back, face or
back visible due to excessive sanding
(sand-through), core show through,
and the like. A natural characteristic
such as a knot, split, bark pocket,
mineral streak, other color marks or
streaks, worm holes, or worm tracks
are not considered defects, but rather
are limited in occurrence by one of
the applicable grades. Allowable but
unrepaired or poorly repaired natural
characteristics may be considered as
defects.
Delamination: A separation of two
or more plies in a hardwood plywood
panel due to adhesion failure that can
result from a number of causes.
Equilibrium moisture content: The
moisture content eventually
attained in wood exposed to a given
environment. Also, the moisture con-
tent a given wood component would
need to attain to be in balance with its
environment.
BACK
PRESS FAULT
DELAMINATION
BARBER POLE
CORES
GLOSSARY OF HARDWOOD PLYWOOD TERMS
PBC
VC
MDF