TECH 320 – Non-Metallic Processes Lumber Lecture Deacon 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”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 – 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