Timbers Flashcards
What is a Coniferous tree
A coniferous tree is a tree that grows fast and has a looser grain and therefore produces softwood.
What is a Deciduous tree
Deciduous trees are trees that grow slowly and have a dense grain and so they produce hardwoods.
What is Plywood
Plywood is a type of manufactured board that is multiple layers of cross grain wood glued together, can be easy to bend and is quite strong.
What is Chipboard
Chipboard is a type of manufactured board that is made up of wood chips glued together, it is hard and strong and easy to finish.
What is Sterling board
Sterling board is a type of manufactured board that is hard heavy and strong.
What is Block board
Block board is stronger and heavier type of plywood due to the solid timber core with veneers laid on each edge
What is Hardboard
Hardboard is a type of manufactured board that is light quite hard and finishes well.
Name 6 timber stock forms
Rough sawn, Planed squared edge, Planed all round, Manufactured boards, Mouldings, Natural timber
Name 6 Hardwoods
Oak, ash, mahogany, teak, birch, beech
Name 6 softwoods
Pine, spruce, fir, redwood, cedar, larch
Name 6 manufactured boards
Plywood, chipboard, MDF, Sterling board, block board, hardboard
Why are natural woods less consistent than natural boards
Strength is effected by moisture
Highly combustible
More susceptible to insect or fungal attack
Is easier to break along the grain (anisotropic)
Why is copper based materials often used in wood preservatives
It is naturally occurring and has anti-fungal properties
How is wood most often enhanced+explain
Veneering
A slice of wood with grain glued onto the top of a wood panel and used to give nice finishes.
What is the difference between a wastage and addition process
A wastage process takes away from a piece of material
whereas an addition process adds more material to it-usually in a joint
Name 3 joints used in woodwork
Comb joint (dovetail)
Dowel joint
Mitre joint
Mortise and tenon
What are knock down fittings
Knock down fittings are fitting that are designed to be able to come apart and be easy to re-assemble.
This makes the item easier to transport as it can be collapsed e.g. ikea furniture
What is dry rot
Dry rot is the rot caused by poor seasoning which results in extra moisture-the rot is caused when the moisture exceeds 20%
What is woodworm
Woodwork is when timber decays due to small beetles eating away at the wood and leave frass/wood dust behind
What is milling
Milling is the process that cuts out a desired groove or cavity with a spinning piece in a path dictated by CAM-it can also change depth so the groove or cavity can be cut deeper at different parts
What is routing
Routing is a process similar to milling but has a larger range of movement and can be used on larger objects
What is turning (lathe)
Turning is a process where the piece is spun at high speed and a fixed cutting tool is slowly moved into contact with the wood-can also be done with metal but it more dangerous
What are the two types of seasoning
Air seasoning and kiln seasoning
What does seasoning wood do
Greater immunity to rot and decay
Increased strength and stability
Helps preservatives to penetrate
Helps make wood less corrosive to metals
What is air and kiln seasoned wood used for
Air:outside
Kiln:inside
What are some disadvantages of natural timber
Weaker when wet
Highly combustible
Highly susceptible to fungal or insect attack and rot
Anisotropic-not equal strength all over
Describe rough sawn wood
Wood that comes directly from seasoning and still has rough edges from initial conversion
Describe planed squared edge
Wood that has one edge planed accurately but the rest is still rough sawn
Describe planed all round
Planed all round is wood that is planed all over to give it a smooth finish-this usually takes 3mm off each side
What is SCL and LVL and what is it used in
Structural composite lumber and laminated veneer lumber-used in buildings and construction due to its even strength and being less prone to defects
What are 3 reasons why wood might be finished
Preventing water absorption
Protection against decay
Protection against insect attack
Enhance appearance
What is a stain
A stain is like a paint but it still shows off the grain of the wood, however it is not very protective
What are three wood finishes that can be used to protect the wood from the weather
Polyurethane varnish
Water based paints
Pressure treating
Yacht varnish
Danish oil
Teak oil
What is a butt joint
A butt joint is where two faces of wood are put into contact with an adhesive in between
What is a dowel joint
A dowel joint is when two faces of wood are put into contact with small hardwood pegs-dowels- machined into both faces of the wood to help hold it together-can be used with adhesive too
What is a mitre joint
A mitre joint is when two pieces are put into contact and glued however the pieces are sawn at an angle (usually 45°) so that when the joint is put together it makes an angled joint-used for picture frames
What is a comb and dovetail joint
A comb joint is when the ends of two pieces are cut to have interspersed ends which can then be slotted together and glued which yields a stronger joint due to higher surface area
Dovetail is the same thing except the ends will be angles so there is mechanical strength as well as adhesive
What is a mortise and tenon joint
A joint where one piece of wood has a rectangular housing-known as a mortise
and the other piece has a rectangular end sticking out-known as a tenon
Then adhesive is spread (usually in the mortise) and the joint is clamped together
What is a housing joint
One piece of wood has a groove routed which is the same width as the depth of the second piece
Then the second piece is inserted, can be with glue if it is wanted to be a permanent joint
What is a half lap joint
When both pieces have half of the depth sawn off and then lay on top of each other
then they can be glued or machined together
What are some examples of knock down fittings and briefly explain
Modesty blocks-small polymer block that holds screws and allows them to be taken out
Barrel nut and bolt-a cross dowel and bolt is inserted and then tightened with an Allen key
Cam-lock connector-a metal dowel is drilled into the side of a piece and then a cam hole is drilled and a cam is put around the dowel-when the cam is rotated the dowel can come out
What are the three types of turning
Turning on a:
Face plate-the timber is fixed on one face and spun the circumference is spun-used for bowls
Chuck-the timber is held between a set of jaws so it can be machined while turned
Between centres-work is held on a central axis where it is turned upon and the diameter is reduced-used for table legs
What is lamination
Lamination is the process of bonding materials, typically wood veneers and wood layers
What is steam bending
Steam bending is when combined steam and heat make a wood more malleable to bend along the grain and the wood is bent in a former when in this state.
Then the wood is left to cool and the former is taken off
What does PVA stand for
Polyvinyl acetate
What is jig or fixture
A jig and fixture both hold work in place while it is being worked on
A jig guides the tool also
