2.5 - Timbers Flashcards
What is newly cut timber, which has not been seasoned, also called?
Green timber
Why does timber need to be seasoned?
- Newly cut timber (green timber) is seasoned to reduce its moisture content.
- This is done to prevent rotting.
What are the two types of timber seasoning?
- Air dried timber
- Kiin dried timber
How is timber air seasoned?
- Air dried timber is separated and stacked under a protective, roofed structure, but with open sides so that air can circulate.
- This is a slow process.
How is timber kiln seasoned?
- Kiln dried timber is a quicker process.
- The kiln is filled with steam, and the moisture content gradually reduced, to dry out the wood.
- This is a more expensive treatment, but enables timber to be sold more quickly requiring much less storage space.
How is medium density fibreboard (MDF) made?
- Waste hardwood or softwood is broken down into fibres and combined with a resin binder.
- It is pressed into sheets which are dense and very strong.
How is plywood made?
- Thin layers or veneers of wood are glued together.
- Each layer has its wood grain rotated at 90° to each other to produce a composite material that is strong in all directions.
How is chipwood made?
Wood chips of varying sizes are mixed with resin, pressed (to create a strong bond) and formed into a sheet.
Exam Style Question:
Explain one way in which softwoods and manufactured boards can be made to look like more expensive hardwoods.
[2]
- Boards may be laminated with a thin veneer of hardwoll on the outer surface.
- They may also be laminated with melamine formaldehyde for use as kitchen worktops or stained.
What is flat pack furniture?
- A manufactured boards (like chipboard) are used to make flat pack furniture.
- Chipboard is made from small particles of timber and dust that are bound together with a resin.
- It is more consistent than natural wood making them easier to work with, drill and cut due to the lack of grain or knots.
What are the advantages of flat pack furniture?
- Boards are cheaper than natural woods
- Board is dimensionally stable so can be transported, stored and assembled with ease.
- Chipboard has no grain and can be drilled and cut with ease.
- Can be finished with veneers to give different surface finishes and colours.
What are the disadvantages of flat pack furniture?
- Flat pack furniture chips easily when knocked.
- It will swell or distort if it gets wet.
Why is larch a suitable material for outdoor use?
- Larch is durable, hard and resistant to extremes of climate.
- Its natural oil content makes it suitable for decking, fencing, posts and marine use.
Why are beech and oak good materials for children’s toys.
Hardwoods that are hard and durable such as beech and oak are selected for toy making, as they have a dense grain and can be sanded to a smooth surface or easily painted.
What are the two main forms that timber is supplied in
Timber is supplied in two main types:
- rough sawn
- planed all round (PAR)
What is ‘rough sawn’ / ‘rough cut’ timber?
- Timber that has been cut at a sawmill and which doesn’t have planned edges.
- uses include garden fence posts and some building work.
What is planed all round (PAR) timber?
- PAR is a term used to indicate that the timber is planed all round, meaning that both the edges and sides have been planed.
- Planed timber is used for interior work where the timber is likely to be seen.
Hardwood and softwood are normally sold in lengths called…
planks, boards and moldings.
- Planks and boards refer to the proportional dimensions of the timber.
- Moulding refers to a decorative pattern that has been cut using a spindle moulder.
What are woodscrews?
- Woodscrews join two pieces of wood together and provide strength to a joint.
- They can also be used to attach locks, hinges and other hardware.
- They come with different shaped heads for different tasks.
Woodscrews often need a hole to be ___________ through both pieces of wood.
pre-drilled
Explain the process of pre-drilling two pieces of wood.
- A pilot hole is drilled into the two pieces of wood. It should be narrower than the diameter of the screw.
- A clearance hole is drilled into the top section, slightly wider than the diameter of the shank.
- If a countersunk screw is being used, the hole should be drilled to the depth of the screw head to allow the screw head to sink just below the surface.
What are moldings?
- Specially shaped sections of wood.
- These can be seen around door frames, known as architrave, windows and skirting board.
What are dowel rods?
- Dowel rods are circular lengths of timber that are supplied in a variety of diameters.
- Fluted dowel pins, pre-cut into short lengths are used for wood joints.
What are some of the different knock down fittings used in flat pack furniture?
- Cam lock fitting
- Connecting or block fitting
- Cross dowel fitting
What is a cam lock fitting? (Knock down fittings)
- Cam or locking screws come in two parts.
- The cam, shaped like a disk, fits into a pre-drilled hole in one piece of timber.
- A connecting screw from the second piece of timber connects with the cam fitting to pull the two panels tightly together.
What is a connecting or block fitting? (Knock down fittings)
- Plastic corner blocks join two pieces of timber together at right angles.
- Screws inserted into ready-made holes hold the two pieces together.
What is a cross dowel fitting (also known as scan fitting)? (Knock down fittings)
- A bolt hole is drilled through one piece of wood and into the connecting piece.
- A dowel hole is drilled laterally across the bolt hole and the cross dowel (metal pin) is slotted in.
- The two are aligned and the screw tightened to bring the joints together.
Exam Style Question:
Explain why knock down fittings would be suitable for kitchen cabinets.
[2]
- KD fittings can be easily assembled with a simple selection of tools.
- They provide a strong enough join, are lightweight and can be quickly dismantled without damaging the item.
What are hinges?
- Hinges are used to connect two objects together with a pivot on one edge.
- Allow doors, windows and lids to open and close.
- They are usually made of steel, brass or plastic.
