CHARACTERISTICS OF
WOOD
The pattern of the fibers makes the
FIGURE of the grain. Different figures may be obtained by
Cutting the wood in different
directions;
Using all sections of a tree,
especially deformed or abnormal areas;
Making cuts from species that
have a distinction between the density and color of the wood during the
spring and summer seasons;
Exposing the rays, curly grain,
or ends of the wood as it is cut.
CHARACTERISTICS OF
WOOD
HARDNESS - the capacity of the wood
to resist abuse.
STRENGTH - the inherent resilience
of the wood against force and stress.
SPECIES OF WOOD
There are many varieties of wood
available; however, only particular species are practical for the manufacture
of furniture.
MAHOGANY
Used in both solid and veneer form.
Different varieties include:
African mahogany
West Indian mahogany
American mahogany
Takes stains well, and it is
usually finished with a light reddish-brown or brown stain that brings out the
figure
ROSEWOOD
An ornamental wood found
principally in Brazil.
The heartwood starts to decay
before the tree is mature. By the time the tree is felled the center is hollow
and the wood can only be cut in half-round flitches.
The wood color runs from red to
brown, and it is streaked with black lines of resin.
TEAK
White sapwood and golden yellow
heartwood in the young tree, but when the heartwood is seasoned, it changes to
a brown mottled with dark streaks.
A pleasant, aroma emanates from the
heartwood and it retains this fragrance for many years.
Teak timber is strong, of average
hardness, and of medium weight.
EBONY
Grows in India and Ceylon, has a
narrow trunk with black, charred-looking bark, white sapwood, and heartwood
with an intense black color.
Jamaican or American ebony is
produced from a tree or shrub which has a trunk that seldom grows more than
four inches in diameter. The heartwood has a rich dark brown color, great
weight, and exceptional hardness.
WALNUT
Widely used in solid and veneer
work.
American black walnut varies in
color from light, creamy sapwood to warm grays and light brown.
Its pores are irregular but large
in size and evenly distributed.
It has a wide range of figures
including burl, crotch, stumpwood, plain stripe, and highly figured longwood.
OAK
Color spread from white to light
and reddish brown. Its pores are large in the spring wood and decrease
abruptly in summer wood.
It has an unusually large ray
extending from the center to the bark.
MAPLE
Cut from American or Canadian
forests of sugar, hard, or rock maple trees.
Light pink to reddish brown in
color. It has very small regular pores that require no filling and a hard
texture that makes it difficult to work.
RED GUM
Reddish brown heartwood and grayish
white sapwood.
Has very small pores and a smooth
surface, but the texture is very soft.
It does not hold up well under hard
use as it dents and warps easily..
ORIENTALWOOD
A unique timber from Queensland,
Australia.
Brown with an overcast of salmon,
green, gray, and sometimes black bindings.
SATINWOOD
Comes from Ceylon, India, and the
West Indies.
It has a silk sheen and a golden
yellow color that mellows with age.
MYRTLE BURLS
Cut from California and Oregon
trees in which the plain wood, stump wood, and burl figures have unusual
designs.
The pores are numerous and
regularly distributed; these finish as highlights that make the wood more
attractive.
CHERRY wood
light to dark reddish brown in
color.
The pores are rather close; the
grain has a very slight figure; and the texture is medium hard..
SUGAR-KNOTTY PINE
Popular because of its knotty
appearance.
This wood has a very soft texture
and is generally made into veneer for hardcore plywood.
The wood is whitish or cream-.
PECAN or HICKORY
a reddish brown color that is often
accented with dark streaks.
The grain has very little figure,
and the pores are small and require only slight filling.
Other woods are:
Japanese and Korean ash;
American aspen and birch;
African avadire, bubinga, sapeli,
tigerwood, and zebrawood;
Philippine narra and paidao; and
primavera.
TYPES OF WOOD
MATERIALS
SOLID WOOD is cut entirely from a
single log. It is strong and durable; therefore, it is usually used to make
the structural parts of furniture. It is not a practical substance for all
parts as it warps easily and has an expansion/contraction problem. Also, it is
in limited supply and, as a consequence, is expensive.
TYPES OF WOOD
MATERIALS
VENEER is a thin sheet or layer of
fine or costly wood that is cut from a log or part of a log called a FLITCH
VENEERING is the technique of
gluing this sheet to a plain, stable groundwood.
The standard thickness for veneer
is one-twenty-eighth inch. Some may be as thick as one-sixteenth inch or as
thin as one-sixtieth inch.
Special veneers
Cut
from the unusual parts of the tree.
BURL VENEERS, sliced from the
thickened, twisted fibers of the burl, show a beautiful peacock-tail
pattern.
BUTT or STUMP VENEERS have a
wavy, rippled marking.
CROTCH VENEERS, taken from the
twisted fibers below the fork, have a swirl design.
Veneer surfaces
SLIP MATCHED VENEERS are sheets
joined side-by-side to make it look as if the pattern is repeated.
BOOK MATCHED VENEERS have the
adjacent pieces of the flitch fastened side-by-side like the open pages of a
book.
DIAMOND MATCHED VENEERS use four
pieces cut diagonally from the same material and fitted together to form a
diamond.
INLAY
Veneers cut into small pieces of
various shapes and sizes so that special designs and pictures can be created.
Inlay may be produced through several methods.
MARQUETRY
Each piece of the pattern is
cut individually and then the sections are glued onto a groundwork.
PARQUETRY
An inlay form characterized by
a repeated geometric design. It is built up of blocks or individual
elements which are assembled into patterns that move continuously and
consistently across the groundwork.
BANDING
A form of inlay in which strips
or strings are set in around the edges of a piece as ornamentation.
MOLDING
A strip of shaped or carved wood
that is used both decoratively and practically.
It may be attached to the exteriors
of doors and drawers and the edges of cabinetwork to give a finished
appearance to an item and to enrich its design.
PLYWOOD
A manufactured wood with three or
more plies or pieces glued together, one atop the other, to form a panel.
The grain of each ply is set at
right angles to the one above it.
The construction makes plywood
exceptionally strong both across and along the grain and reduces the natural
tendency of the wood to warp and shrink with atmospheric changes.
LAMINATE
Manufactured wood.
It is built of several thin pieces
that are glued together to form a single board. All the pieces run in the same
direction and the pieces are usually of the same thickness.
CANE
Bamboo bark that has been cut into
thin strips and woven into a web.
The design of the weave may be the
traditional hexagonal style or a variation in the contemporary basket, small
square, or rectangular shapes.
JOINTS AND JOINT
SUPPORTS
A JOINT is the permanent fastening
of two surfaces together. The several types of joints used for wood
construction are the butt, edge, rabbet, dado, lap, miter, mortise-and-tenon,
and dovetail.
JOINTS AND JOINT
SUPPORTS
BUTT or PLAIN JOINTS have the
square end of one piece fitted against the flat edge of the second piece. This
joint will not hold up by itself; it must be reinforced with dowels. Added
strength may also be supplied by a corner block.
JOINTS AND JOINT
SUPPORTS
EDGE JOINTS fasten pieces of wood
together side-by-side. The grain of both parts runs parallel, but the annual
rings should fall in opposite directions.
RABBET JOINTS are made by fitting
one piece into the L-shaped groove cut into the other piece.
LUMBER CUTTING
The way lumber is cut from a log
determines the final appearance of the grain pattern.
There are three ways solid stock is
cut from a log
plain sawing (also called flat
sawing)
quarter sawing
rift sawing.
Cutting
Plain sawing makes the most
efficient use of the log and is the least expensive of the three methods,
Because the wood is cut with various orientations to the grain of the tree,
plain sawing results in a finished surface with the characteristic cathedral
pattern.
Cutting
Quarter sawing is produced by
cutting the log into quarters and then sawing perpendicular to a diameter
line. Because the saw cut is nearly perpendicular to the grain, the resulting
grain pattern more uniformly vertical. Quarter sawn boards tend twist and cup
less, shrink less in width, hold paint
Cutting
Rift sawing provides an even more
consistent vertical grain because the saw cuts are always made radially to the
center of the tree. Because the log must e shifted after each cut and because
there is much waste, rift cutting is more expensive than quarter sawing and is
seldom used.
Because of the limited availability
of some species of wood and the expense of making certain cuts, not all types
of lumber cutting are available in all species. The availability of cuts in
the desired species should be verified before specifications are written.
Types of Veneer Cuts
There are five principal methods of
cutting veneers.
Plain slicing and quarter slicing
are accomplished the same way as cutting solid stock, except the resulting
pieces are much thinner.
Quarter slicing produces a more
straight-grained pattern than plain slicing because the cutting knife
strikes the growth rings at approximately a 90-degree angle.
With rotary slicing, the log is
mounted on a lathe and turned against a knife, which peels off a continuous
layer of veneer. This produces a very pronounced grain pattern that is often
undesirable in fine-quality wood finishes, although it does produce the most
veneer with the least waste.
Types of Veneer Cuts
Half-round slicing is similar to
rotary slicing, but the log is cut in half and the veneer cut slightly across
the annular growth rings. This results in a pronounced grain pattern showing
characteristics of both rotary-sliced and plain-sliced veneers.
Rift slicing is accomplished by
quartering a log and cutting at a 15-degree angle to the growth rings. Like
quarter slicing, it results in a straight-grain pattern and is commonly used
with oak to eliminate the appearance of markings perpendicular to the
direction of the grain. These markings in oak are caused by medullary rays,
which are radial cells extending from the center of the tree
When individual
veneers come from the same piece of log it is called a flitch.
