Specification

20 columbiaforestproducts.com Hardwood Plywood Grading Guide 2015
Knot (pin): A knot ¼" or less in di-
ameter, with no missing knot material.
The center of a pin knot may be dark
up to 1/8" (conspicuous), or natural in
color with no dark center (blending or
inconspicuous).
Knot (sound): Knots that are solidly
xed by growth and that retain their
place in lumber or veneer.
Knothole: Opening produced when
knots drop from the wood in which
they were once embedded.
Lap: A manufacturing defect that
occurs when a portion of a sheet
of veneer splits and subsequently
overlaps itself due to uneven moisture
movement. A lap may occur in a face
and back where it may resemble a
split if the errant portion is still intact
in the lap or a press dent if the errant
portion is missing.
It may also occur in a core compo-
nent wherein it will create a localized
thickness difference in the panel that
will result in the face or back veneer
being sanded off or in the core itself
showing through the face or back.
Medium Density Fiberboard
(MDF): Engineered wood panel
product consisting of wood
reduced to basic lignocellulosic ber
bundles integrated with adhesive and
compressed under heat for use as
a substrate for decorative hardwood
plywood face veneers, paper and
plastic laminates, and high pressure
laminate (HPL), among others.
Mill run: A production lot of panels
produced with the understanding and
agreement between buyer and seller
that all panels in that particular lot will
be shipped by the seller and accepted
by the buyer, without regard to usabil-
ity of any particular panel or portion of
any panel due to any manufacturing
defect or natural characteristic.
Mineral streak: A generally blue-
gray to black elongated discoloration
on the surface of solid lumber or
decorative veneer.
Moisture content: The percentage
by weight of water in wood relative
to the weight of the wood with all the
moisture removed.
Occasional : Occurring on some,
but not all face veneers. Refers to
characteristics such as vine caused
gure (also called vine mark) that may
be present sporadically within a given
run of veneer, but not to the extent it
creates an objectionable condition.
Particleboard (PBC): Engineered
wood panel product consisting
of small wood particles and ber
bundles integrated with adhesive and
compressed under heat for use as
a substrate for decorative hardwood
plywood face veneers, paper and
plastic laminates, and high pressure
laminate (HPL), among others.
Patch: Any repair to a decorative
wood veneer, consisting of synthetic
ller or wood veneer inserts.
Plain sliced: Wood veneer cut roughly
parallel to the pith of the tree on a
GLOSSARY OF HARDWOOD PLYWOOD TERMS
tangent to the growth rings, generally
having a relatively consistent appear-
ance from piece to piece, and usually
producing at least some semblance of
a cathedral grain pattern at some point
during the slicing process.
Ply: A single sheet of veneer forming
one layer in a multi-layered piece of
plywood.
Plywood, hardwood: A panel com-
posed of layers of one or more inner
plies of wood veneer, MDF, PBC, or
other core material joined with an
adhesive to a face and back veneer
of hardwood or decorative softwood
veneer.
Quarter sliced: Decorative face
veneer cut on a radial angle to the
growth rings of the tree by slicing
a quarter log, or a half log as it is
reduced to a point near the pith of
the tree. Typically, quarter sliced
oak (Quercus spp.) veneer will
have relatively straight grain with
pronounced ake across the growth
rings due to the fact that the cut
is roughly parallel to the oak rays
which are wider than in most other
species.
Radial: A line projecting from or
converging upon a center of a round
object. In wood, the radial plane con-
stitutes a line across the growth rings
and parallel to the rays.
Ray: Flattened band of parenchyma
cells projecting from the center of
the tree to the cambium. Present in
all species, but pronounced in some
species, particularly red and white
oak and alder.
Repair: A patch, shim, or natural
or synthetic filler material inserted
SYNTHETIC FILLER
NATURAL WOOD INSERT
HARDWOOD PLYWOOD
VENEER LAP
CORE LAP
RADIAL
7 PLIES
CORE VOID