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© 2009 Nelson Education Ltd. Carpentry First Canadian Edition 1 Chapter 2 Lumber.

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Presentation on theme: "© 2009 Nelson Education Ltd. Carpentry First Canadian Edition 1 Chapter 2 Lumber."— Presentation transcript:

1 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 1 Chapter 2 Lumber

2 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 2 Manufacture of Lumber Logs arrive at a sawmill and the bark is removed A bandsaw cuts the log into planks A series of saws are used to slice, edge and trim The wood is cut to various dimensions Wood is stacked for sticking and then dried

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4 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 4 Manufacture of Lumber (cont.) Lumber is standardized and shipped Measuring terms –Long, narrow surface is the edge –Long, wide surface is its side –The extremities are called ends –Distance across the edge is the thickness –Distance across the side is the width –Distance from end to end is the length

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6 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 6 Plain-Sawed Lumber Common way of cutting lumber Log is cut tangent to annular rings This produces a distinctive grain Least expensive, producing greater widths Shrinks during drying, warps easily Slash-sawed lumber

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8 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 8 Quarter-Sawed Lumber Produces pieces with annular rings at right angles Shrinks less, warps less easily High durability Frequently used for flooring Also called vertical-grain or edge-grain

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10 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 10 Combination Sawing Using technology to cut a log in a way that wastes the least amount and takes a short amount of time

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12 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 12 Moisture Content and Shrinkage Green Lumber – Newly cut wood that hasn’t dried and will shrink – Should not be used in construction – As it shrinks, it usually warps – Subject to decay due to its moisture content – Seasoned wood should be protected from moisture

13 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 13 Moisture Content (MC) Expressed as a percentage Determined by the weight before and after oven drying and dividing that number by the dry weight Lumber used for framing and exterior should have an MC that does not exceed 19%

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18 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 18 Drying Lumber Can be air dried and stacked in piles with spacers Can be stacked and dried in huge ovens called kilns that provide controlled temps, humidity and air circulation Kiln drying takes less time but is more costly

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21 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 21 Drying Lumber (cont.) Recommended MC for exterior finish lumber is 12% Lumber with 8-10% MC is for interior trim and cabinet work Moisture meters are used to measure moisture content

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23 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 23 Lumber Storage Store lumber so it is protected from moisture and other hazards Keep lumber off the ground Cover with a tarp, leaving room for air circulation

24 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 24 Lumber Defects A defect is any fault that detracts from its appearance Warps are caused by drying lumber too fast, poor storage, or surfacing lumber before it is dry Splits (called checks) are caused by uneven drying Cracks (called shakes) run between and parallel to annular rings

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26 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 26 Lumber Defects (cont.) Lumber with a lot of juvenile wood can warp or twist Knots are cross-sections of branches in the trunk of the tree Pitch pockets are small cavities holding pitch Wane is bark on the edge of lumber Pecky wood has small grooves through the grain

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28 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 28 Lumber Grades and Sizes Largest manufacturer of softwood is Western Wood Products Association (WWPA) Three categories include: – Boards–under 2 inches thick –Dimension–2 to 4 inches thick –Timbers–5 inches and thicker

29 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 29 Lumber Grades Hardwood grades established by the National Hardwood Lumber Association Firsts and seconds (FAS) is the best grade Each piece must be at least 6” wide by 8’ long Next best grade is called Select (4”x6’) No. 1 common grade allows narrower widths by shorter lengths

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31 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 31 Lumber Sizes Rough lumber directly from the sawmill is close to nominal size Planing reduces the thickness and width to standard and uniform sizes Nominal size (what the piece is called, for example a 2x4) is not actual size (1½ x 3½)

32 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 32 Lumber Sizes (cont.) Lumber sizes are indicated by a series of numbers. Thickness″ × Width″ × Length′ For example, 1″ × 10″ × 12′ (One inch thick × 10 inches wide and 12 feet long)

33 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 33 Lumber Names Three general types: 1x6 2x6 4x6 Boards – 1 inch or less in thickness e.g. 1x6 Dimension Lumber – 2 inches in thickness e.g. 2x6 Timbers – larger than 2 inches in thickness e.g. 4x6

34 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 34 Actual vs. Nominal Actual dimensions of lumber are smaller than the name implies. For example: –A nominal 2x6 6″6″ 2″2″ 2x6

35 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 35 Actual vs. Nominal Is actually 1 ½″ × 5 ½″ 5 ½″ 1 ½″ 2x6 Actual dimensions of lumber are smaller than the name implies. For example: A nominal 2x6

36 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 36 Actual vs. Nominal NominalActualNominalActual 1x4¾″ x 3 ½″2x41 ½″ x 3 ½″ 1x6¾″ x 5 ½″2x61 ½″ x 5 ½″ 1x8¾″ x 7 ¼″2x81 ½″ x 7 ¼″ 1x10¾″ x 9 ¼″2x101 ½″ x 9 ¼″ 1x12¾″ x 11 ¼″2x121 ½″ x 11 ¼″

37 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 37 Actual vs. Nominal Nominal (inches) Actual (millimetres) Nominal (inches) Actual (millimetres) 1x419 x 382x438 x 89 1x619 x 1402x638 x 140 1x819 x 1842x838x 184 1x1019x 2352x1038 x 235 1x1219 x 2862x1238 x 286 37

38 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 38 Lumber Volume Lumber may be purchased by the piece. –e.g., 36 – 2x8–16′ Large quantities of lumber are often purchased by the board foot (bdft). e.g., 750 bdft of 2x4’s This is typically done at the wholesale level. Also allows for varying board lengths.

39 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 39 Board Foot Measure (cont.) Formula for figuring board feet is: Bdft = # pieces × Thickness″ × Width″ × Length′ ÷ 12 Note: Thickness (inches), Width (inches), & Length (feet) Example – How many board feet are in 180 pieces of 2x8  16′ long? Answer: 3840 bdft. 180 × 2 × 8 × 16 ÷ 12 = 3840 bdft

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41 © 2009 Nelson Education Ltd. Carpentry First Canadian Edition 41 Conclusion Wood can be air dried or kiln dried There are different grades of wood Care must be taken to store wood in a dry place with good air circulation


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