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28問 • 2年前

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may have a variety of noticeable grain patterns •Tends to twist and cup, and wears unevenly •Tends to have raised grain •Shrinks and swells less in thickness, more in width nasi

PLAINS SAW LUMBER

Wears more evenly with less raised grain and warping •shrinks and swells less in width, more in thickness

QUATER SAW LUMBER

come from the conifers (evergreens) which have needles instead of leaves, e.g. pine

SOFTWOOD

come from the broad-leaved or deciduous trees. Most Philippine timber are of this latter kind

HARDWOOD

isthesofter,youngerouterportion of a tree that lies between the cambium (formative layer just under the bark) and the heartwood. - Itismorepermeable,lessdurable and usually lighter in color than the heartwood. thanos

SNAP WOOD

theolder,hardercentral portion of a tree. - usuallycontainsdeposits of various materials that frequently give it a darker color than sapwood. - isdenser,lesspermeable and more durable than the surrounding sapwood. - Thecentralcoreofthe log, it is composed of inactive cells and serves only as a mechanical support pusu

HEARTWOOD

This is measured by the compression which a piece of timber undergoes when a weight is applied to it. tibe

HARDNES

The amount of piece will bend before breaking . Softwoods are generally brittle while most hardwoods are flexible luffy

FLEXIBILITY

PROPERTIES OF WOOD

HARDNES FLEXIBILITY DURABILITY STRENGTH

Caused by the attack of fungi.

DECAY

Cracks or lengthwise separation across the annual rings of growth caused by irregular shrinkage during drying. Checks are formed when the circumference shrinks more than the interior section of the log.

CHECKS

These are cracks between and parallel to the annual rings of the growth. kasug

SHAKES

These are irregular growths in the body of a tree which interrupt the smooth curve of the grain. The fibers of the tree are turned from their normal course and grow around the knot at that point of the tree tornilyu

KNOTS

These are well- defined openings between annual rings containing solid or liquid pitch. pantalun

PITCHPOCKET

This is the lack of wood on the edge or corner of a piece.

WANE

- Any variation with the plane surface of the piece caused by unequal shrinkage of the board. There are several forms of warp:

WRAPPING

a distortion of the board in which the edge is convex or concave longitudinal

CROOKS

a distortion of the board in which the face is convex or concave longitudinal.

bow

a distortion of the board in which the face is convex or concave across the bo basu

CUP

a distortion of the board in which one corner is raised. durut

TWIST

refers to lumber cut tangent to the annual rings or growth or, in commercial practice, cut with annual rings at an angle 0 to 45. Plainsawn lumber is preferable when a pleasing pattern is required, as in wall paneling. atyu ne

PLAIN SAWING

refers to wood cut radially to the annual rings of growth parallel to the rays or, in commercial practice, cut with the annual growth rings at an angle 45 to 90. Quartersawn lumber is desirable because it has less shrinkage than plainsawn lumber, and this is important where joints must be kept tig last 2 mins

QUATER SAWING

Lumber less than 2” thick and less than 8”

STRIPS

Pieces less than 2” thick and at least 8” wide.

BOARD LUMBER

Pieces more than 2” and less than 5” in any dimension.

DIMENSION LUMBER

Pieces 5” or more on the smallest dimension

TIMBERS

which the lumber is exposed to the air. langi air

AIR DRYING

which warm moist air or superheated steam is used to heat the wood and drive out moisture. The ideal condition in seasoning is for the moisture from the interior of the wood to replace the surface moisture which vaporizes. When the moisture from the

KILN DRYING

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ユーザ名非公開 · 10問 · 3年前

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