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General info:
http://en.wikipedia.org/wiki/Lumber#Dimensional_Lumber
http://www.inthewoodshop.org/methods/wwc05g.shtml
http://www.arrowmoulding.com/surfacing_terminology.html

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Abbreviations:
	- BF - Board Foot
	- KD - Kiln Dried
	- S1S - surfaced one side
	- S2S - surfaced two sides
	- S1E - surfaced one edge
	- S2S1E - surfaced two sides, one edge.
	- S1S2E - surfaced one side, two edges.
	- S4S - surfaced four sides
	- SM - surface measure
	- H/M - hit and miss.  Boards have been surfaced/planed just enough
	        to reveal the grain and figure of the board.  Surfaced boards
	        will measure 15/16".
	- NHLA - National Hardwood and Lumber Assoc

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- Alder has its own unique grading standards and major Alder producers
  do not us NHLA Grading Rules

- Alder, Superior Grade:
	- Top Grade for Alder.
	- Yield of 83.33% (10/12 ths) to 100% clear-face cuttings on one face.
	- Yield of 66.66% (8/12 ths) to 100% clear-face cuttings on other face.
	- Clear cuttings must be a minimum size of 3" x 6' or 4" x 3'.
	- Pin Knots are not a defect in Alder

- Frame Alder, aka Knotty Alder
	- Available in three grades: Premium, Standard and Econo

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National Hardwood and Lumber Assoc (NHLA) Grading Rules:

- A board foot (BF) is the unit of measurement for hardwood lumber.
  A board foot is 1 foot long x 1 foot wide x 1 inch thick.
  The formula for determining BF is:
	Width in feet x length in feet x thickness in inches
  The percentages of clear wood required for each grade are based on
  this 12' unit of measure.

- Surface measure (SM) is the surface area of a board in square feet.
  The formula for determining SM is:
	Width in feet x length in feet
	Round up or down to the nearest whole number.

- Board widths falling exactly on the half inch are alternatively rounded
  up or down.

- Board lengths that fall between whole foot increments are always rounded
  down to the nearest whole foot.

- Rough sawn lumber thickness is expressed in quarters of an inch.
  ex: 1" = 4/4.  The majority of US rough sawn hardwood lumber is 1" to 2".

- Surfaced/Planed lumber thickness is:
	if final thickness is <= 1.5", rough sawn thickness - 3/16"
	if final thickness is > 1.5", rough sawn thickness - 1/4"

- Grading:
	- Rules were developed with random width and length lumber in mind.

- FAS Grade
	- Minimum board size is 6" x 8'.
	- Yield of 83.33% (10/12 ths) to 100% clear-face cuttings.
	- Clear cuttings must be a minimum size of 3" x 7' or 4" x 5'.
	  The minimum width and length will vary depending on
	  species moisture content.
	- Both faces of the board must meet the minimum requirement for FAS.

- FAS One Face (FAS/1F, or F1F)
	- One face must meet FAS requirements
	- Other face must meet Number 1 Common grade requirements

- Select Grade
	- Same as F1F except for the minimum board size required.
	- The minimum board size is 4" x 6'.

- Prime Grade
	- Not actually standard NHLA definition.
	- Square edged and virtually wane free.
	- Minimum clear yield will be select or slightly better,
	  appearancece is a main factor.
	- Minimum board size varies depending on species, region, and supplier.

- Comsel Grade
	- Not actually standard NHLA definition.
	- Minimum clear yield should be Number 1 Common or slightly better,
	  appearance is a main factor.
	- Minimum board size varies depending on species, region, and supplier.

- Number 1 Common (No 1C)
	- Commonly referred to as the Cabinet grade.
	- Minimum board size is 3" x 4'.
	- Yield of 66.66% (8/12 ths) to 83.33% (10/12 ths) clear-face cuttings.
	- Clear cuttings must be a minimum size of 3" x 3' or 4" x 2'.
	  The minimum width and length will vary depending on
	  species moisture content.
	- Both faces of the board must meet the minimum requirement for No 1C

- Number 2A Common (No 2AC)
	- Commonly referred to as the Economy grade.
	- Minimum board size is the same as No 1C.
	- Yield of 50% (5/12 ths) to 66.66% (8/12 ths) clear-face cuttings.
	- Clear cuttings must be a minimum size of 3" x 2'.
	- If the poorest face of a board meets the minimum requirements for
	  No 2AC, it does not matter what the grade of the better face is.

- NHLA Grading rules allow the following characteristics in the clear
  cutting percentages for all grades (these characteristics are not
  considered to be defects)
	- Heardwood and Sapwood
	- Burls
	- Gum Streaks (naturally occuring only in cherry)
	- Mineral Streaks
	- Glassworm (usually associated with ash)
	- Sticker Mark

- NHLA grading rules do not allow the following characteristics in the
  clear cuttings for all grades (these characteristics are considered
  to be defects).
	- Bark Pocket
	- Bird Pecks (except in Hickory and Elm)
	- Checks
	- Decay or Rot
	- Unsound Knot
	- Sound Knot
	- Split
	- Sticker Stain
	- Wane
	- Worm Holes (holes 1/16" - 1/4")
	- Pith
	- Grub Holes (holes > 1/4")

- Number 1 and 2 white Color Sortings
	- A colour selection typically used for hard maple, but can be
	  applied to any species where sapwood clear cuttings are desired,
	  such as ash, birch, and soft maple.

- Number 1 white
	- Both faces and edges of the clear cuttings must be all sapwood.

- Number 2 white
	- One face and both edges of the clear cuttings must be sapwood and
	  not less than 50% sapwood on the reverse face.

- Sap and better
	- Minimum of one sapwood face in the clear cuttings.

- Red one face and better
	- Minimum of one heartwood face in the clear cuttings.
	- Applied to species where heartwood clear cuttings are desired
	  such as cherry, oak, walnut, gum, and even birch and maple
	  (in certain applications).

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