Скачать или смотреть Wood as Building Material - Prerequisite Course #03: Tension, drying, movement

The main material we use can still frustrate and confuse even after years of use. So understanding some basics at the start will alleviate one obstacle to learning the craft.

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Additional Content on Wood for woodworking.
Dimensioning Wood:    • Stock Prep & Dimensioning in Woodworking  

Tree Butchery:    • Tree Butchery  
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Teachers Notes No. 3 - Wood:
   • Teachers Notes No. 3 - The Prerequisite Co...  
open questioning
props
vocabulary terms (Contributions and corrections are welcome for terms utilized in this video.)

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Prompts:

biology: tree cell structures, different cells, cell shapes
history: how did they get building material for things like cabinets and homes in middle ages (hint: not much different than today)
science: make a hygrometer from strips of different species of wood which will move differently

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Vocabulary:

homogeneous - the same throughout

reaction wood - wood that grew under stress or load so that as material is removed so is force holding it in a shape.

late growth - a trees growth during dormancy

early growth - a trees growth during the growing season (spring, summer)

lathe - woodworking tool that spins the material so blades can be presented to it to accomplish work.

table saw - woodworking tool where material is passed over a round spinning blade. used to cut straight lines.

fence - a brace to move work against to create a consistent cut.

riving knife - safety device on a table saw that prevents wood from pinching on the back of the blade that also travels up and down and maintains a consistent distance from the blade during that movement.

hard wood - dicot, angiosperms trees, generally broad leaf with a dormant cycle (deciduous). have a more complex cell structure than softwoods.

soft wood - wood from a gymnosperm tree like pines. many are evergreen with needles for leaves. simpler cell structure than hardwoods. "soft" does not refer to the hardness of wood as many are harder than "hardwoods".

knot - scar from branch amputation.

free water - water not bound in a cell

bound water - water that has entered a cells structure through osmosis.

growth ring - annual ring in wood created by the difference between late and early growth hence one ring per year of growth or growth cycle.

Kiln Dried - artificial drying method where heat, moisture control, vacuums or a combination are used to extract the bound water from a trees cells until it reaches equilibrium with the air.

Air Dried - natural method of drying wood that utilizes time to evaporate the water from cells through osmosis.

Cookie - cross section of a tree trunk

rift sawn - board sawn so that the growth rings cross it at +/- 45 degrees

flat sawn - board sawn so that the growth rings are parallel with the width of the board.

quarter sawn - board sawn so that the growth rings are perpendicular with the width of the board.

frame and panel - method of construction to capture the movement of wood and create a stable shape.

sheet goods - man made wood products used in construction and woodworking of a consistent dimension design to be stable.

plywood - a sheet good where woods are layered in stacks perpendicular to each other then bonded with glue, heat and pressure.

osb - a sheet good made of shredded wood layered in such a way to create a stable mat that is then compressed with heat, pressure and glue.

mdf - sheet good make of sawdust, heat, pressure and glue.

lingnum - latin for wood

rip cut - cutting wood along the length of a trees growth

cross cut - cutting wood across it's growth rings or perpendicular to it's growth.
split