問題一覧
1
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
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Pieces more than 2” and less than 5” in any dimension.
DIMENSION LUMBER
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come from the conifers (evergreens) which have needles instead of leaves, e.g. pine
SOFTWOOD
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Lumber less than 2” thick and less than 8”
STRIPS
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Pieces less than 2” thick and at least 8” wide.
BOARD LUMBER
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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
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a distortion of the board in which the edge is convex or concave longitudinal
CROOKS
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which the lumber is exposed to the air. langi air
AIR DRYING
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Wears more evenly with less raised grain and warping •shrinks and swells less in width, more in thickness
QUATER SAW LUMBER
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a distortion of the board in which one corner is raised. durut
TWIST
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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
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These are cracks between and parallel to the annual rings of the growth. kasug
SHAKES
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This is measured by the compression which a piece of timber undergoes when a weight is applied to it. tibe
HARDNES
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Caused by the attack of fungi.
DECAY
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The amount of piece will bend before breaking . Softwoods are generally brittle while most hardwoods are flexible luffy
FLEXIBILITY
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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
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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
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This is the lack of wood on the edge or corner of a piece.
WANE
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Pieces 5” or more on the smallest dimension
TIMBERS
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come from the broad-leaved or deciduous trees. Most Philippine timber are of this latter kind
HARDWOOD
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These are well- defined openings between annual rings containing solid or liquid pitch. pantalun
PITCHPOCKET
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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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a distortion of the board in which the face is convex or concave across the bo basu
CUP
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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
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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
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- Any variation with the plane surface of the piece caused by unequal shrinkage of the board. There are several forms of warp:
WRAPPING
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PROPERTIES OF WOOD
HARDNES FLEXIBILITY DURABILITY STRENGTH
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a distortion of the board in which the face is convex or concave longitudinal.
bow