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Selecting Lumber. Interest Approach Look at the piece of wood you are given. Write down as many observations as possible. Look at the piece of wood you.

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Presentation on theme: "Selecting Lumber. Interest Approach Look at the piece of wood you are given. Write down as many observations as possible. Look at the piece of wood you."— Presentation transcript:

1 Selecting Lumber

2 Interest Approach Look at the piece of wood you are given. Write down as many observations as possible. Look at the piece of wood you are given. Write down as many observations as possible. Measure the dimensions of the piece of wood. Write them down with your observations. Measure the dimensions of the piece of wood. Write them down with your observations.

3 Interest Approach What happens between cutting down a tree and you buying the wood as lumber? What happens between cutting down a tree and you buying the wood as lumber? How is lumber graded and stored? How is lumber graded and stored? How can you determine which type of lumber to buy? How can you determine which type of lumber to buy?

4 Problem: How are lumber and other wood products produced and processed?

5 Lumber Production and Processing trees are cut down trees are cut down transported to the sawmill transported to the sawmill logs are soaked until sawing time logs are soaked until sawing time prevents checking, cracking, and warping prevents checking, cracking, and warping bark is removed bark is removed plain-sawed or quarter-sawed plain-sawed or quarter-sawed

6 Plain-Sawing Cutting the log on a tangent to the growth rings Cutting the log on a tangent to the growth rings faster faster less waste less waste lower cost lumber lower cost lumber used in buildings used in buildings

7 Quarter-Sawed Lumber Cutting the log perpendicular to the growth rings Cutting the log perpendicular to the growth rings less likely to warp, shrink, and swell less likely to warp, shrink, and swell used to make furniture used to make furniture

8 Drying Lumber Green lumber Green lumber Freshly cut lumber with 20 percent or more moisture. Freshly cut lumber with 20 percent or more moisture. Seasoning Seasoning Process of drying lumber to the point where it is ready to use. Process of drying lumber to the point where it is ready to use.

9 Drying Lumber Air drying Air drying Set outside to dry Set outside to dry Takes 1-3 months Takes 1-3 months Moisture content to 15% Moisture content to 15% Kiln-dried Kiln-dried uses a large oven or kiln to dry uses a large oven or kiln to dry Moisture content to 6% to 12% Moisture content to 6% to 12%

10 After Drying Run through a planer to make it smooth and dimensional Run through a planer to make it smooth and dimensional

11 Plywood: a series of layers (3, 5, or 7) glued together with the grains arranged at right angles to each other to form a 4×8 sheet a series of layers (3, 5, or 7) glued together with the grains arranged at right angles to each other to form a 4×8 sheet strength is maximized strength is maximized

12 Particle Board 4×8 sheet made by gluing wood chips, splinter, and sawdust together 4×8 sheet made by gluing wood chips, splinter, and sawdust together used under countertops and in some furniture used under countertops and in some furniture cheaper cheaper warps quickly when it gets wet warps quickly when it gets wet

13 Waferboard (OSB or Chip board) gluing wood chips to form 4×8 sheets gluing wood chips to form 4×8 sheets cheaper cheaper more water resistant more water resistant Used in roof sheathing and subflooring Used in roof sheathing and subflooring

14 Paneling 1/8 or ¼ inch sheet of wood or hardboard with a wood grain surface 1/8 or ¼ inch sheet of wood or hardboard with a wood grain surface Cheap paneling may be wood with wood grain contact paper on the surface. Cheap paneling may be wood with wood grain contact paper on the surface.

15 Veneer Thin layer of material that is glued to an inferior quality material. Thin layer of material that is glued to an inferior quality material. low cost furniture is often particle board with a veneer wood grain surface layer low cost furniture is often particle board with a veneer wood grain surface layer

16 Problem: How is lumber graded and selected for use?

17 Lumber Grading and Selection Wood for lumber is divided into two broad categories, “softwood” and “hardwood”. Wood for lumber is divided into two broad categories, “softwood” and “hardwood”. Refers to the type of tree they come from Refers to the type of tree they come from

18 Hardwood lumber cut from broad-leaved (deciduous) trees that drop their leaves in the fall lumber cut from broad-leaved (deciduous) trees that drop their leaves in the fall Oak, maple, cherry Oak, maple, cherry Fine furniture Fine furniture

19 Softwood Lumber cut from coniferous (cone- bearing) evergreen trees with needle-like leaves Lumber cut from coniferous (cone- bearing) evergreen trees with needle-like leaves construction lumber construction lumber

20 Softwood Grading Softwood grading is based on: Softwood grading is based on: Appearance, Appearance, Strength, or Strength, or Combination of the two. Combination of the two.

21 Softwood Grading Defects which can affect both appearance and strength include: Defects which can affect both appearance and strength include: knots, knots, checks, checks, splits, splits, decay, decay, stains, stains, insect holes insect holes

22 Matching Lumber to job Use the lowest quality of lumber suitable for the purpose. Use the lowest quality of lumber suitable for the purpose. Requires a knowledge of the characteristics of each species of wood. Requires a knowledge of the characteristics of each species of wood.

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24 Properties of Wood Good understanding of wood properties is essential for intelligent lumber selection. Good understanding of wood properties is essential for intelligent lumber selection. Properties Include: Properties Include: Hardness Hardness Bending strength Bending strength Stiffness Stiffness Compression strength Compression strength Toughness Toughness

25 Problem: How is lumber sized, purchased, and stored?

26 Worked lumber Wood that has been Wood that has been Shaped (trim) Shaped (trim) Matched (tongue-and-groove) Matched (tongue-and-groove) Patterned (molding) Patterned (molding)

27 Actual vs. Nominal Dimensions The difference between nominal and actual (dressed) dimensions of lumber is the result of: The difference between nominal and actual (dressed) dimensions of lumber is the result of: Planing, Planing, Shrinkage that occurs during drying. Shrinkage that occurs during drying.

28 Actual vs. Nominal Dimensions Nominal dimensions (2×4, 1×6, etc.) are used when ordering lumber Nominal dimensions (2×4, 1×6, etc.) are used when ordering lumber Project planner uses the actual planed dimensions (¾×3½, 1½×7¼, etc.) to determine the number and length of boards needed Project planner uses the actual planed dimensions (¾×3½, 1½×7¼, etc.) to determine the number and length of boards needed

29 Actual vs. Nominal Dimensions Softwood nominal widths are 2, 3, 4, 6, 8, 10, and 12 inch. Softwood nominal widths are 2, 3, 4, 6, 8, 10, and 12 inch. Standard available lengths are even feet from 6 to 20. Standard available lengths are even feet from 6 to 20.

30 Actual vs. Nominal Dimensions To find the actual width for nominal widths of 6 inches or less drop ½ inch. To find the actual width for nominal widths of 6 inches or less drop ½ inch. For nominal widths of over 6 inches drop ¾ inch to find the actual width. For nominal widths of over 6 inches drop ¾ inch to find the actual width.

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33 Linear feet length in feet without regard to thickness or width length in feet without regard to thickness or width Thickness of these sheets vary through a range of ¼, 3/8, ½, 5/8, to ¾ inch Thickness of these sheets vary through a range of ¼, 3/8, ½, 5/8, to ¾ inch Generally sold by the 4×8 sheet Generally sold by the 4×8 sheet Plywood, Plywood, Particle board, Particle board, Paneling are generally sold by the 4×8 sheet. Paneling are generally sold by the 4×8 sheet.

34 Actual vs. Nominal Dimensions All of these materials are priced either by the square foot or by the sheet. All of these materials are priced either by the square foot or by the sheet. Other building materials, such as roofing and siding, are sold by “the square”. Other building materials, such as roofing and siding, are sold by “the square”. “The square” actually means 100 square feet of surface coverage. “The square” actually means 100 square feet of surface coverage.

35 Ordering Lumber Do not order large quantities of lumber long in advance Do not order large quantities of lumber long in advance When storing lumber, care should be taken to avoid: When storing lumber, care should be taken to avoid: Warping, Warping, Staining, and Staining, and Moisture absorption problems. Moisture absorption problems.

36 (Picture Courtesy, Interstate Publishers, Inc.)


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