Selecting Wood and Lumber

Mr. Rodriguez

Ag Mechanics

A. Kinds of wood1. Softwood: Comes from needle leaf,

evergreen trees, called conifers.a. White Pine – Easy to work with and straight.

Used for shelving, interior finish, and exterior trim

b. Yellow Pine- Wear resistant and tough. Used for benches, stairs, & other places that require a semi-hard surface.

c. Fir- Light, straight, and strong. Used for framing members, siding, sheathing, & gates.

Softwoods cont

d. Redwood- Excellent decay resistance. Used for posts, fences, patios, and siding.

e. Cedar- Light and easy to split. Used for fence posts, sills, and shingles

f. Spruce- Light, straight, strong, and resonant. Used for aviation and musical instruments.

2. Hardwoods: Come from broad leaf trees that loose their leaves each fall season. = Deciduous

a. Oak- Tough, strong, and open-grained. Used for floors, interior finish, barrels, and furniture.

b. Walnut- Beautiful brown open grain. Used for fine furniture.

Hardwoods cont.

c. Maple- Very durable and light grained. Used for floors, furniture, and guitar necks

d. Mahogany- Reddish in color. Used for fine furniture.

e. Birch- Is used for surface veneer on cabinets and doors.

B. Kinds of lumbar and wood panels.

1. Wood cut into uniform thickness, width, and length, is called lumber.

a. Boards=Lumber used for flooring, sheathing, paneling, and trim.

b. Dimension lumber= Is used for sills, plates, studs, & rafters.

c. Timbers= Lumber used for posts, beams, & heavy stringers.

2. Wood Panels( Usually 4’x8’)a. Plywood- Made of thin layers of wood glued

together, with the wood grain turned at right angles in alternating layers.

b. Composite Board- Made of a core of wood fibers bonded on either side with veneer

c. Hardboard- Is made of refined wood fibers, pressed together, to form a hard, dense material

Wood Panels Cont.

d. Particle board- Is made from wood flakes, chips, and shavings bonded together.

e. Wafer board- Is made of high quality flakes of wood ( @ 1 ½” square) bonded together under heat and pressure.

f. Oriented strand board- Made of wood fibers bonded to together in successive layers, arranged at right angles.

3. Lumber Grades

A. Lumber grades are based on appearance, and soundness of the wood.

B. Lumber defects in or on the wood reduces its strength, durability, and usefulness.

Lumber blemishes, only impairs the wood’s appearance.

C. Common lumber defects

1. Knots- Embedded branches or limbs in the lumber.

2. Holes can be caused by mishandling, or insects & worms

3. Splits and checks are separations of the wood fibers along the grain.

Common defects cont.

4.Wane is the presence of bark or absence of wood along the board’s edge

5. Warp- is any variation from a plane surface including cups, bows, crooks, and twists.

4. Plywood Grades

a. A lettering system is used to indicate quality of the veneers on the face and back of the panel

1. “N” is suitable for natural finishing.

2. “A” is suitable for painting.

3. “B” has a solid surface.

5. Factors to consider when selecting wood

1. Quality construction does not require that all the lumber be of the best grade.

2. Several grades of lumber may be used in a single structure.

3. Good economical construction requires the proper use of the lowest grade lumber suitable for the purpose!