Fabricating

Fabricating involves joining, cutting and shaping materials so that a product can be made. Timbers are used to produce a variety of products and can be joined in many ways.

Lamination

A is a thin layer of material. is strengthened by having the timber glued at right angles to each other. Timber is easier to bend along the grain, but when another sheet of timber is glued at right angles it becomes hard to bend in any direction because the grains are at right angles to each other. As the plywood becomes thicker, the less likely it is to flex at all. This is referred to as and is a desirable feature.

Different sheets of timber are layered on top of each other, each at a 90 degree angle to the last, to form plywood. Shown aside an image of completed plywood.

Veneering

A veneer is a thin layer of wood. Plywood is made of layers of veneer laminated together. A veneer can be applied to cheaper materials, such as or , to make them appear more expensive.

A pile of manufactured boards, veneered with a variety timbers with a gloss finish.

Use of screws

Screws create a strong joint in timber and can be unscrewed if required. There are two main head designs for screws:

flat
Phillips

A countersunk hole, drilled at a horizontal so a screw would sit on the surface, and a counterbored hole, drilled straight down so that a screw would sit beneath the surface.

A specific type of screwdriver is required to fit each of the different head designs. Using a countersink hole ensures that the screw lies flat with the timber and stops accidents or things such as clothes becoming entangled on the screw. A is narrower than the screw thread and makes it easier for the screw to go in.

A Philips screw, shaped like a plus (+), alongside a flat screw, shaped like a minus (-).

Nailing

Nails come in a range of shapes and sizes, including:

round wire nails - do not pull through thin timber as they have a large flat head
panel pins - for holding thin boards onto timber as they are small, often used with adhesive
oval nails - less likely to split timber as they spread the grain less than round wire nails

A hammer is used to drive a nail through the wood grain and is quicker than fitting a screw. It is common for the nail head to be pushed below the surface of the wood so that it can be covered using a filler and improve the appearance.

Adhesives

PVA and contact adhesive are commonly used when working with wood:

PVA - commonly used wood glue that is white when wet and dries clear, it takes time to set and must be clamped while the glue sets to produce a permanent and strong join
contact adhesive - commonly used for sticking different materials onto wood, but care must be taken as it gives off solvent fumes

Wastage

Wastage processes cut materials away to the required shape, eg sawing, , filing, drilling and sanding. Waste costs money and has an environmental impact, so must be minimised wherever possible.

Addition

Addition processes add materials together - for example, assembling, gluing, screwing and nailing.

Wood joints

Joint	Advantages	Disadvantages
Butt	Quick and easy to make with only glue required	Weak, can break easily, isn’t aesthetically pleasing
Dowelled	Can use a jig for accuracy, dowels give the joint good strength	Without the use of a jig it is hard to line up the dowels
Lap	Fairly easy to cut or route	Not very strong, requires glue and panel pins to increase the strength
Housing	Holds a shelf or divider securely within a frame, usually used with lap joints on the corners	Can be difficult to cut on a wide sheet, very accurate marking out and cutting is needed to ensure the shelf is not wonky
Mitre	Commonly used for picture frames, aesthetically pleasing as no end grain is seen	Similar to a butt joint so is weak and often needs reinforcement
Mortise and tenon	Commonly used for joining the legs onto a chair or table, strong joint	Time consuming to cut by hand as the joint is visible and the strength relies on tight-fitting parts
Dovetail	Commonly used for a drawer front that is constantly pulled open, a strong joint, aesthetically pleasing	Difficult to cut by hand

Joint	Butt
Advantages	Quick and easy to make with only glue required
Disadvantages	Weak, can break easily, isn’t aesthetically pleasing

Joint	Dowelled
Advantages	Can use a jig for accuracy, dowels give the joint good strength
Disadvantages	Without the use of a jig it is hard to line up the dowels

Joint	Lap
Advantages	Fairly easy to cut or route
Disadvantages	Not very strong, requires glue and panel pins to increase the strength

Joint	Housing
Advantages	Holds a shelf or divider securely within a frame, usually used with lap joints on the corners
Disadvantages	Can be difficult to cut on a wide sheet, very accurate marking out and cutting is needed to ensure the shelf is not wonky

Joint	Mitre
Advantages	Commonly used for picture frames, aesthetically pleasing as no end grain is seen
Disadvantages	Similar to a butt joint so is weak and often needs reinforcement

Joint	Mortise and tenon
Advantages	Commonly used for joining the legs onto a chair or table, strong joint
Disadvantages	Time consuming to cut by hand as the joint is visible and the strength relies on tight-fitting parts

Joint	Dovetail
Advantages	Commonly used for a drawer front that is constantly pulled open, a strong joint, aesthetically pleasing
Disadvantages	Difficult to cut by hand

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Timbers - EdexcelFabricating