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

3. Wood Properties n Crown: – Photosynthesis occurs here (CO2 + H2O + SUN= Sugar + O2 – Provides some raw materials (for wafer /particle board etc.) n Trunk: – Supports the crown-Provides us with lumber n Roots: – Anchor the tree-Absorb Water & Minerals – Prevent Erosion Crown Roots Trunk n Parts of the Trunk – Outer Bark: Protection against Fire, insects & Disease. – Inner Bark: (Called Bast or Phloem) Cells carry food (SAP) made in 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 n Springwood: Lighter colored, less dense part of each ring (Spring growth). n Summerwood: Darker colored, more dense part of each ring (Summer growth).

4. Wood Classifications nSnSoftwoods –C–Conifers: Cone or needle bearing trees nEnExamples: Spruce, Fir, Hemlock nHnHardwoods –D–Deciduous: Broad leaf trees - shed leaves in winter –E–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

5. 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 ”

6. Drying / Seasoning Lumber n Moisture Content : Percentage of moisture to wood cells n Green Lumber (GR): – Can contain 30-300% moisture content – a green 2 X 4 X 8 can have up to 3 gallons of h 2 0 n Air Dried (AD): – One month to a year. yields a 12-15% MC (in some species) n Kiln Dried (KD): – One to four weeks yields a 10% or less MC

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

8. Purchasing Lumber n Linear or “Running” Foot – Price per foot of material – Molding, dowel n Square Foot/age – Sheet Goods: Plywood, Wafer Bd., Paneling, Particle Bd. – Calculate Area (Length X Width) n 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

9. 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. 64.00 12 5. 64.00 60.00 4.00 12 5.3 64.00 60.00 40 36 4 12 5.3 64.00 60.00 40 36 4 12 5.33 64.00 60.00 40 36 4 36 4 Answer= 5.33 BD. FT.

10. 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. 64.00 144.4 640 576 640 Answer=.44 BD. FT. 144.44 640 576 640 576 64

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