woods & plastics (termi)

• plains sawn lumber


  • 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
• Quarter sawn lumber


  • has more even grain patterns

  • Wears more evenly with less raised grain and warping

  •shrinks and swells less in width, more in thickness
• Softwoods 


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


  Come from the broad-leaved or deciduous trees. Most PH timer are of this latter kind.
• classification of wood

  softwoods, hardwoods
• Sapwood


  is the softer, younger outer portion of a tree that lies between cambium
• Sapwood


  more permeable, less durable and usually lighter in color than heartwood
• Sapwood


  The portion of the log near the periphery which is generally lighter in color than the central potion
• Sapwood


  Contains living cells and takes an active part in the live process of a tree
• Sapwood


  contains more organic matter than the central core of the log, more susceptible to blueing fungi and wood-boring insects, not durable
• Heartwood


  The older, harder central portion of a tree
• Heartwood


  usually contains deposits of various material that give dark color
• Heartwood


  denser less permeable and more durable than surrounding sapwood
• Heartwood


  Central core of log, composed of inactive cells and serves only as mech support
• Structure of wood

  Sapwood, heartwood
• Properties of wood

  Hardness, flexibility, strength, durability
• Hardness


  measured by the compression which a piece of timber undergoes when a weight is applied to it
• Flexibility


  amount of piece will bend before breaking. Softwoods are generally brittle while hardwoods are flexible
• Defects of wood

  decay, checks, shakes, knots, pitchpockets, wane, warping
• Decay


  by attack of fungi
• Checks


  Cracks or lengthwise separation across the annual rings of growth
• Checks


  Formed when the circumference shrinks more than the interior section of the log
• Shakes


  Cracks between and parallel to the annual rings of the growth
• Knots


  Irregular growths in the body of tree which interrupt the smooth curve of the grain
• Pitchpockets


  Well-defined openings between annual rings containing solid or liquid pitch
• Wane


  Lack of wood on the edge or corner of a piece
• Warping


  any variation with the plane surface of the piece caused by unequal shrinkage of board
• Forms of Warp

  Crook, bow, cup, twist
• Bow


  Distortion of the board in which the FACE is convex or concave longitudinal
• Crook


  Distortion of the board in which the EDGE is convex or concave longitudinal
• cup


  a distortion of the board in which the fade is convex or concave ACROSS THE BOARD
• Twist


  distortion of the board in which one corner is RAISED
• Methods of sawing wood

  Plainsawing, quartersawing
• Plainsawing


  refers to lumber cut tangent to the annual rings or growth...0° to 45°
• Plainsawn lumber


  Preferable when a pleasing pattern is required, as in wall paneling
• Quartersawing


  Refers to wood cut rasially to the annual rings of growth parallel to the rays....45° to 90°
• Quartersawn lumber


  Desirable because it has less shrinkage than plainsawn lumber
• Classification of lumber

  Strips, board lumber, dimension lumber, timbers
• Lumber


  Wood that is used in construction
• Lumber


  Classified by its size and dimensions measured in inches