| BACK
VENEER |
The veneer sheet on the underside of a plywood panel, corresponding
in thickness, and often in species, to the face veneer on the
upper or exposed surface. Its grain runs parallel to the grain
of the core, and crosswise to the grain of the cross-banding.
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| BIRD'S
EYE |
Due
to local sharp depressions in the annual rings, accompanied by
considerable fiber distortions. Once the depressions are formed,
succeeding growth rings follow the same contour for many years.
Rotary veneer cuts the depressions crosswise, and shows a series
of circlets called bird's eyes. It occurs only in a small percentage
of Maple trees. |
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| BLISTER |
Produced
by an uneven contour of the annual rings. The veneer has the effect
of being blistered. Must be cut rotary or half-round. |
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| BOOK
MATCHING |
Achieved
when successive veneer leaves in a flitch are turned over like
the pages in a book and are glued in this manner. Since the
reverse side of one leaf is a mirror image of the succeeding
leaf, the result is a series pairs. Individual panels can be
matched this way or you can achieve this look over many panels
by sequence-matching the panels. Book matching is the most common
match. A common problem in book matching is when the "tight"
and "loose" sides are matched and reflect light and stains differently.
This may yield color variations in some species which may be
minimized by proper finishing techniques.
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| BROKEN
STRIPE |
A
modification of ribbon stripe, the markings tapering out and producing
a broken ribbon. If the log describe in ribbon stripe has a twist
in the grain the stripes are short or broken. |
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| BURL
VENEER |
Produced
from a large, wartlike growth on the trunk of the tree. The grain
pattern typically resembles a series of eyes laid side by side.
Obviously the veneers leaf sizes are generally small and additionally
are defective. While producing beautiful patterns, burl veneer
is difficult to work with. |
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| BUTT
MATCHING |
Achieved
when veneers are matched as described for book matching but the
ends of the sheets are also matched. At times, the veneer being
used is not long enough to cover the desired panel heights. In
this case the veneer leaves can also be flipped end for end and
the ends matched. |
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| CATHEDRAL |
A
grain appearance characterized by a series of stacked "V" and
inverted "V". Pattern common in plain-sliced (flat-cut) veneer. |
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| CENTER
MATCHING |
Each
panel face is made with an even number of flitch sheets with a
center line appearing at the midpoint of the panel and an equal
number of veneer sheets on each side of the center line. The number
of leaves on the face are always even, but the widths are not
necessarily the same. |
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| CHECKS |
Small
slits running parallel to the grain of wood, caused chiefly by
strains produced in seasoning. |
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| CORE |
There
are four types of core construction used in plywood panels: a)
Lumber Core: Consists of a heavy core of sawn lumber between crossbands.
The thick center core permits doweling, splining and dovetailing.
b). Veneer Core: Method of plywood construction consisting of
3,5,7 or more plies of veneer laid with grain direction of adjacent
plies at right angles to each other. c). Particle Board: This
type of core consists of chips or flakes of resin-coated wood
fused together under heat and pressure to form a core for plywood.
d). Mineral Core: Used for fireproof panel construction. Veneers
are bonded to a hard noncombustible material. |
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| CROSS
BREAK |
Separation
of the wood cells across the grain. Such breaks may be due to
internal strains resulting from unequal longitudinal shrinkage
or to external forces. |
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| CROSS
FIRE |
Figures
which extend across the grain as mottle, fiddle-back, raindrop
and finger-roll are often called cross figure or cross fire. A
pronounced cross fire adds greatly to the beauty of the veneer. |
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| CROSSBAND |
The
veneer sheet between the core and face veneer. Its grain runs
at right angles to the grain of adjacent layers, thereby providing
the remarkable stability of hardwood plywood. |
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| CROSSBAR |
Type
of figure or irregularity of grain resembling a dip in the grain
running at tight angles, or nearly so, to the width of the veneer. |
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| CROTCH
VENEER |
Produced
from the portion of the tree just below the point where it forks
into two limbs. The grain is twisted, creating a variety of flame
figures. Often resembles a well formed feather. The outside of
the block produces a swirl figure that changes to full crotch
flame figure as the cutting approaches the center of the block. |
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| CURLY |
Found
mostly in Maple or Birch, and is due to the fibers being distorted
and producing a wavy or curly effect in the veneer. |
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| CUT
MARKS |
A
raised or hollowed cross grain cut caused generally by a nick
in the knife. |
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| DEFECT,
OPEN |
Checks,
splits, open joints, knotholes, cracks, loose knots, wormholes,
gaps, voids, or other openings interrupting the smooth continuity
of the wood surface. |
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| DIAMOND
MATCH |
This
is generally done with a straight grain veneer. If a rectangle
is divided into 4 quadrants, the veneers match at an angle to
the quadrant line, and the grain forms a "V" at these lines. The
result is a diamond shape formed by the grain directions. |
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| DISCOLORATIONS |
Stains
in wood substances. Common veneer stains are sap stains, end stains,
blue stains, stain produced by chemical action caused by the iron
in the cutting knife coming in contact with the tannic acid of
the wood, and those resulting from the chemical action of the
glue. |
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| FACE |
The
better side of any plywood panel in which the outer plies are
of different veneer grades. Also veneer spliced to a certain pattern
and cut to exact size. |
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| FIDDLE
BACK |
A fine, strong, even, ripple figure as frequently seen on the
backs of violins. It is found principally in Mahogany and Maple;
cut occurs sometimes in other woods. |
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| FIGURE |
The
pattern produced in a wood surface by annual growth rings, rays,
knots, deviations from natural grain such as interlocked and wavy
grain, and irregular coloration. Appears across the grain. Mottle,
fiddleback and raindrop are often called cross figure or cross
fire. |
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| FLAKE
(RAY) |
Flake
figure is developed only in those species which have very heavy
medullary ray growth, specifically Oak, Lacewood, and Sycamore.
When the saw or knife cut is directly on or near to the radial,
it is close to parallel with the medullary ray and therefore develops
the "Flake" effect. |
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| FLAT
CUT |
Also
called Plain Slicing, it is the most common method of veneer manufacturing,
producing a grain pattern known as cathedral. Because each leaf
in the flitch is similar, a consistent and even matching pattern
is possible. Flat cut veneer is ideally suited for wall panels
and furniture. |
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| FLITCH |
a)
A Section of a log made ready for cutting into veneers.
b) After cutting, all bundles are laid together in sequence as
they were sliced. |
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| GRAIN |
Size
and arrangement of the cells and pores of the living tree. Grain
is not synonymous with figure. Woods fall into three groups: Fine
grained (Birch, Cherry, Maple, etc.), medium grained (Walnut,
Mahogany, etc.) and coarse grained (Oak, etc.).) Coarser grained
woods can usually be cut to develop a more conspicuous pattern. |
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| HALF
ROUND SLICING |
Similar
to rotary peeling, also producing a high veneer yield. Used primarily
to add width to narrow stocks by increasing the plane of cut.
Also used to enhance a particularly wild grain pattern. Matching
is possible because the leaves can be kept in sequence. Half round
cutting may be used to achieve "flat cut" veneer appearance. |
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| HARDWOOD |
General
term used to designate lumber or veneer produced from broad-leafed
or deciduous trees in contrast to softwood, which is produced
from evergreens or coniferous trees. |
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| HEARTWOOD |
The
non-active center of a tree generally distinguishable from the
outer portion (sapwood) by its darker color. |
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| HERRINGBONE |
Veneer
strips are used and matched to both sides of the center line,
at an angle. The resulting appearance is reminiscent of the bones
of a fish as they are attached to the back bone. |
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| HOLES,
WORM |
Holes
resulting from infestation of worms. |
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| JOINT |
The
line between the edges or ends of two adjacent sheets of veneer
or strips of lumber in the same plane. |
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| KNOTS,
INCONSPICUOUS PI |
Sound
knots 1/4 inch or less that do not contain dark centers. Inconspicuous
or blending pin knots are barely detectable at a distance of 6'
to 8', do not seriously detract from the overall appearance of
the panel, and are permitted in all grades. |
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| KNOTS,
OPEN |
Opening
produced when a portion of the wood substance of a knot has dropped
out, or where cross checks have occurred to produce an opening. |
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| KNOTS,
SOUND, TIGHT |
Knots
that are solid across their face and fixed by growth to retain
their place. |
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| LAMINATION |
The
process of gluing or bonding the component sections of the plywood
into a single permanent until stronger than the original wood
itself. |
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| LONGWOOD |
The
trunk of the tree that begins just above the stump and continues
to just below the crotch. Most veneers are cut from longwood by
quarter, rotary or flat cutting. |
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| LOOSESIDE |
In
knife-cut veneer, that side of the sheet that was in contact with
the knife as the sheet was being cut. The bending of the wood
at the knife edge causes cutting checks. |
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| MATCHING
OF BURLS, CROTCHES, STUMP |
Because
of their generally exotic grains, these wood figures need special
treatment when being matched into faces. Burls and crotches in
particular have a tendency to be buckled. In the process of making
a panel face, the veneer needs to be flattened and patched if
needed. They also have a tendency to develop fine hairline splits,
so must be carefully handled in further manufacturing. This extra
labor and care adds to the expense of using these grains, but
the results are usually well worth the cost. |
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| MOTTLE |
A
variegated pattern which consists principally of irregular, wavy
fibers extending for short distances across the face. If there
is also some irregular cross figure in a log with a twisted interwoven
grain, the broken stripe figure becomes a mottle. |
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| PARTICLEBOARD |
A
panel composed of small particles of wood and wood fiber that
are bonded together with synthetic resin adhesives in the presence
of heat and pressure. |
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| PECKY |
Pockets
of disintegrated wood caused by localized decay, or wood areas
with abrupt color change related to localized injury such as bird
peck. Peck is sometimes considered as a decorative effect such
as bird peck in pecan and hickory or pecks in cypress. |
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| PLY |
A
single sheet of veneer, or several pieces laid with adjoining
edges, which form one layer in a piece of plywood. |
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| PLYWOOD
HARDWOOD |
A
panel composed of an assembly of layers or plies or veneer (or
veneers in combination with lumber-core, particleboard-core, MD-core,
hardboard-core material) joined with an adhesive. Except for special
constructions, the grain of alternate plies is always approximately
at right angles, and the face veneer is usually a hardwood species. |
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| QUARTER
SLICING |
This
cut requires the largest diameter logs and produces straight grained
veneers. The quarter slicing of oak can result in the appearance
of flake. |
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| RANDOM
MATCHED |
(Mismatched)
A panel having the face made up of specially selected dissimilar
(in color and grain) veneer strips of the same species and generally
V-grooved at the joints between stripes to stimulate lumber planking. |
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| REVERSED
DIAMOND |
This
is commonly done with a straight grain veneer. A rectangle is
divided into 4 quadrants. The grain direction is from the center
point to the outside edge in each quadrant. The resulting appearance
is that of a series of "Vs" formed by the grain match at the joint
line pointed in at the center point. |
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| RIBBON
STRIPE |
Result
of quarter-slicing a log and the appearance actually is between
broken stripe and plain stripe. It gives the general appearance
of a ribbon sometimes slightly twisted. |
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| RIFT
CUT |
Produced
by cutting at a slight angle to the radial to produce a quartered
appearance without excessive ray flake. The rift cut method, commonly
used for Oak, can only be used on sizable logs. Rift cut veneer
can easily be sequenced and matched. |
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| ROPE |
If
the twist in the grain of broken stripe is all in one direction,
a rope figure results. |
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| ROTARY
PEELING |
The
log is turned in a circular motion against a knife, peeling off
a continuous thin sheet of wood veneer (like unrolling wrapping
paper). It is the most economical method of producing veneer,
resulting in the highest yield. The grain is inconsistent and
leaves are most difficult to match. This type of veneer is best
suited for paint grade or utility surfaces. |
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| 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. |
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| RUNNING
MATCH |
The
panel face is made from components running through the flitch
consecutively. Any portion of a component or leaf in starting
the next panel. |
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| SAPWOOD |
This
is the outer portion of the tree. As additional layers of growth
accumulate on the outer perimeter, the inner layers of the sapwood
becomes heartwood. Sap is lighter in color and the differentiation
in color and thickness of the sap layer varies considerably by
species. |
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| SLICED |
Veneer
produced by thrusting a log or sawn flitch into a slicing machine
which shears off the veneer in sheets. |
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| SLIP
MATCHING |
Means
that veneer leaves in a flitch are "slipped." Successive veneer
leaves in a flitch are "slipped" one alongside the other and edge-glued
in this manner. The result is a series of grain repeats, but no
pairs. The danger with this method derives from the fact that
grain patterns are rarely perfectly straight. Sometimes a grain
pattern "runs off" the edge of the leaf. A series of leaves with
this condition could usually make a panel look like it is leaning.
In the book matching the pairs balance each other. |
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| SOFTWOOD |
General
term used to describe lumber or veneer produced from needle and/or
cone-bearing trees. (See Hardwood). |
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| SPECIES |
A
distinct kind of wood. |
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| SPLICED
FACE VENEER |
Face
veneers that have been joined in any one of several matching effects
through the careful factory process of tapeless splicing. |
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| SPLITS |
Separations
of wood fiber running parallel to the grain. |
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| STREAKS,
MINERAL |
Natural
discolorations of the wood substance. |
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| STUMP
VENEER |
Produced
from the base of the tree. Here the grain pattern is always swirly
twisted and often accompanied by cross fire and patches of burl.
The sizes are normally small. |
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| TIGHT
SIDE |
In
knife-cut veneer, that side of the sheet that was farthest from
the knife as the sheet was being cut and containing no cutting
checks (lathe checks). |
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| VENEER |
A
thin sheet of wood, rotary cut, sliced or sawn from a log or flitch.
Veneering goes back to the early days of the Egyptians, about
3,500 years ago. Down through the years and cultures, veneering
has enriched furniture and architectural interiors with sheets
of rare and beautiful woods bonded to other plain, sturdy wood
based substrates to form a panel. |
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