TECH 320 – Non-Metallic Processes Lumber Lecture Deacon Band.

TECH 320 – Non-Metallic Processes

Lumber LectureDeacon Band

Logging

Harvesting Trees

• Felling

– Severing the tree from the stump and bringing it to the ground.

• Extraction

– Pulling the tree from the forest area to a landing or roadside.

• Processing

– Delimbing and topping the tree, and then cutting the stem into logs (‘bucking’).

• Loading

– Sort, stack and then load out onto logging trucks.

• Trucking

– Deliver the logs from the landing to the mill for final processing.

Logging

• Felling – The modern way

Logging

• Extraction

Logging

• Loading and Trucking

Lumber Mill

• Logs are scaled “Log Scaler”– Determines volume and grade of the wood

• Logs are debarked

• Logs are decked– Sorting by species, size, and end use

• Lumber, plywood, chips

Lumber Mill

• Head Saw “Head Rig”

– Breaks log into cants and flitches with a smooth edge

• Cants: Unfinished logs to be further processed

– Cants may be further broken down by a resaw or gang edger into multiple flitches and/or boards

• Flitches: Unfinished planks

• Edging

– Takes the flitches and trims off all irregular edges

• The result is 4-sided or Dimensional lumber

Lumber Mill

• Trimming– Squares the ends of the lumber at typical

lengths• 8’, 10’, 12’, 16’. Etc…

• Drying

Lumber Drying

• Kiln 2-3 weeks– Done in oven in 3 basic steps:– Step 1: high humidity, low heat.– Step 2: low humidity, raise heat.– Step 3: low humidity, high heat.

• Air– 2-3 years

Moisture Content

• Furniture lumber 8% M.C. or less.

• Construction lumber 12% M.C. or less.

Sticking

• Allows for air space and movement of air through the stack of lumber

Planing

• Smoothes surface of the lumber leaving a uniform width and thickness.

Lumber Classifications

• Use Classifications.– Yard lumber: sizes & grades used for

ordinary construction and building, 2” or less in thickness.

– Structural lumber: 2” or more in thickness and width.

– Factory & shop lumber: lumber produced for remanufacturing purposes.

Lumber Classifications

• Manufacturing Classifications.– Rough lumber: lumber that has not been

dressed (surfaced).– Dressed lumber: has been surfaced; S1S,

S2S, S4S, S1E, S2E.– Worked lumber: has been dressed and

also matched, ship lapped or patterned.

Lumber Grading

• Hardwood– Firsts: best grade, free of surface defects

(91 2/3%).– Seconds:83 1/3% free of defects.– Selects: 4” wide & 6’ long.– Commons: #1, #2, sound wormy, #3A,

#3B, below grade.

Lumber Grading

• S1S

– Surfaced one side

• S2S

– Surfaced two sides

• S4S

– Surfaced four sides

• S1E

– Surfaced one edge

• S2E

– Surfaced two edges

Lumber Grading

• F.A.S.: Firsts and seconds (most common usage)

Lumber Grading

• Softwood.

– #1 & #2 clear.

– Selects C&D.

– Commons, grades 1-5.

• 1 – Construction: paints well, paneling

• 2 – Standard: larger knots, paints fair

• 3 – Utility: many knots, sheathing, subfloor

• 4 – Economy: splits, concrete formwork

• 5 – Economy: very rough, concrete forms

Wood Scrap Products

• Hardboard: made from wood fibers and glue under pressure and heat.– Standard and Tempered: tempered is like

standard, only with more heat and pressure.

Standard Hardboard

Tempered Hardboard

Wood Scrap Products

• Flakeboard: made from wood flakes and glue.

• Particle board: wood chips and glue.– Low,medium, and high density; density

determined by the chip size.

• Fiberboard: wood fibers and glue (very little pressure).

Flakeboard

• Oriented Strand Board (OSB)

Particle Board

Low Density

Particle Board

Medium Density

Particle Board

High Density

Fiber Board

Wood flakes and glue

Plywood Types

• Lumber core: solid wood is in the middle (hardwood).

• Veneer core: veneer core plys.

• Particle board: particle board core with plys.

Lumber Core

Veneer Core

Particle/mdf Core

Veneer Grades

• Hardwood– G1S: good one side.– G2S: good two sides.

Veneer Grades

• Softwood:

Board Feet

• Board feet: depth(T) x width(W) x length(L) / 144(inches) = Board Feet

• A measurement of volume of lumber

One Board Foot

Lumber Processing Flow Chart

Debarked Tree Trunk

Solid Lumber Veneer Wood Scraps

Plain Quarter Rift Hogs Sawed/ Sawed/ Sawed Flat Edge Grained Grained

Peeler Dried Classified Rotary Flat Quarter Cut Sliced Sliced Dried Dried Kiln Air Veneer Plywood

Graded Lumber Veneer Particle Core Core Board Core Graded Hard Flake Fiber Particle Board Board Board Board Tempered Standard Low Medium High Density Density Density

Interior Plywood Grades

Panel Grade Face Back Inner Plies Most Common UsagesN-N N N C Cabinet doors/furniture where both sides show

N-A N A C Cabinet doors/furniture where both sides show

N-B N B C Cabinet doors/furniture where one side shows

N-D N D D Cabinet doors/furniture where one side shows

A-A A A D Cabinet doors, built-ins, and furniture where both sides show

A-B A B D Alternate for A-A. Face is finish grade; back is solid and smooth.

A-D A D D Finish grade face for paneling, built-ins, and backing.

B-B B B D Two sides paintable.

B-D B D D Utility grade. One paintable side. Used for backing/cabinet sides.

C-D C D D Sheathing, temporary structural uses, and subfloor. Unsanded.

Underlayment C plugged D C,D For underlayment/subfloor-underlayment under tile and carpeting.

Exterior Plywood Grades

Panel Grade Face Back Inner Plies Most Common UsagesA-A A A C Outdoors, where appearance of both sides is important.

A-B A B C Alternate for A-A, where appearance of one side is less important. Face is finish grade.

A-C A C C Soffits, fences, base for coatings

B-C B C C For utility uses such as farm buildings, some kinds of fences, base for coatings.Ê

C-C plugged C C plugged C Excellent base for tile, backing for wallcoverings, high-performance coatings.Ê

C-C C C C Unsanded, for backing and rough construction exposed to weather.Ê

Veneer Quality

N Intended for natural finish. Selected all heartwood or all sapwood. Free of open defects.A Used for natural finish in less demanding applications. Smooth and paintable. Neatly made repairs only.B Solid surfaced veneer. Can be painted. Repair plugs and tight knots allowed.C Sanding defects permitted that do not impair strength or serviceability.

C plugged Improved C grade, closer limits on knotholes/splits.D Used only in interior type. Knots/knothole to 2 1/2" max dimension. Limited splits allowed.