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General Woodworking Units 2 & 3 Wood Properties

General Woodworking Units 2 & 3 Wood Properties. Mr. Nelson Darien High School. Wood Properties. Crown. Trunk. Roots. Crown: Photosynthesis occurs here (CO2 + H2O + SUN= Sugar + O2 Provides some raw materials (for wafer /particle board etc.) Trunk:

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General Woodworking Units 2 & 3 Wood Properties

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  1. General Woodworking Units 2 & 3 Wood Properties Mr. Nelson Darien High School

  2. Wood Properties Crown Trunk Roots • Crown: • Photosynthesis occurs here (CO2 + H2O + SUN= Sugar + O2 • Provides some raw materials (for wafer /particle board etc.) • Trunk: • Supports the crown -Provides us with lumber • Roots: • Anchor the tree -Absorb Water & Minerals • Prevent Erosion • Parts of the Trunk • Outer Bark: Protection against Fire, insects & Disease. • Inner Bark: (Called Bast or Phloem) Cells carry food (SAP) madein leaves downward. • Cambium Layer: 2 cells wide, allows the tree to increase in girth. New wood forms on inside(Xylem); New bark on outside(Phloem). • Sapwood: Newer, lighter colored, Springy growing part of the wood which carries sap from roots upward. • Heartwood: Older, less alive, darker colored part of the wood. Was sap wood. More Ridged. • Pith: soft, Center of the tree. Allows for vertical growth. Considered a defect. • Medullary Ray Cells: Channels which carry food/sap horizontally. • Annual Rings: New Ring Each Year • Springwood: Lighter colored, less dense part of each ring (Spring growth). • Summerwood: Darker colored, more dense part of each ring (Summer growth).

  3. Wood Classifications • Softwoods • Conifers: Cone or needle bearing trees • Examples: Spruce, Fir, Hemlock • Hardwoods • Deciduous: Broad leaf trees - shed leaves in winter • Examples: Oak, Birch, Beech Sawing Methods • Plain Sawing: • Most common, easiest method • Called “Flat Grained” on softwoods • Produces “U Shaped” face grain • Least expensive method • Wood warps the most

  4. Quarter Sawing: • Called edge or Vertical Grained on softwoods • Produces straight almost parallel face grain • More Expensive • More difficult, log is 1st “quartered”, then sawed tangent to rings (65-90 degree angle) • Rift Sawing: • Logs “quartered” then sawed at a 35-65 degree angle • Yields more, wider boards with pronounced rays • Most expensive • Surface Condition: • Rough lumber: straight off the saw blade • Dressed: Surfaces planed S1S, S2S or S4S • “NOMINAL SIZE”= Before Planing : “2 X 4” • “ACTUAL SIZE”= After Planing: “1 1/2” x 3 1/2”

  5. Drying / Seasoning Lumber • Moisture Content : Percentage of moisture to wood cells • Green Lumber (GR): • Can contain 30-300% moisture content • a green 2 X 4 X 8 can have up to 3 gallons of h20 • Air Dried (AD): • One month to a year. yields a 12-15% MC (in some species) • Kiln Dried (KD): • One to four weeks yields a 10% or less MC

  6. Lumber Grades • Softwoods • Best& Most Expensive Grade • Select Grade A: “Clear” • Select Grade B Few Knots • Select Grade C More Knots • Select Grade D Most Knots • 2nd Best Grade- Less Expensive • Common # 1-5 • House Trim is Common #2 • Hardwoods • Best& Most Expensive Grade • F.A.S. (Firsts & Seconds) 85-90% clear • 2nd Best, Less Expensive Grade • Select: Good for Furniture, At least 1 good face • 3rd & 4th best Grades • Common # 1 & #2 : 66% clear, narrow boards • Grading done from worst side of board • Lumber sold in “Random widths & Lengths”

  7. Purchasing Lumber • Linear or “Running” Foot • Price per foot of material • Molding, dowel • Square Foot/age • Sheet Goods: Plywood, Wafer Bd., Paneling, Particle Bd. • Calculate Area (Length X Width) • The Board Foot • How Lumber is sold • Volume measurement • 1 Board Foot = 1” X 12” X 12” • Formulas For Board Foot Calculation • “C”=100 Bd. Ft., “M”= 1000 Bd. Ft. • All Fractions get rounded UP to next inch for calculation • Must Carry out answer 2 decimal places • A) Use If LENGTH is given in INCHES T” X W” X L” 144 • B) Use If LENGTH is given in FEET T” X W” X L’ 12

  8. . 64.00 5 . 64.00 60.00 4.00 5 .3 64.00 60.00 40 36 4 5 .3 64.00 60.00 40 36 4 5 .33 64.00 60.00 40 36 4 36 4 12 12 12 12 12 Sample Board Foot Problem Example: 2” X 4” X 8’ Step 1 2 X 4 X 8 12 Step 2 8 X 8 12 Step 3 64 12 Answer= 5.33 BD. FT.

  9. . 64.00 .4 640 576 640 .44 640 576 640 576 64 144 144 144 Sample Board Foot Problem Example: 3/4” X 4” X 16’’ Step 1 1 X 4 X 16 144 Step 2 4 X 16 144 Step 3 64 144 Answer= .44 BD. FT.

  10. Putting It All Together…..A Complete Lumber Order • Should Include : • Species • Lumber Grade • Sawing Method • Amount (Board Footage) • Size Pieces (Nominal T x W x L ) • Surface Condition • (Rough/Dressed s2s, S1s, S4S) • Drying Method

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