Assam ASSEB HSLC Wood Craft key terms

The inner, older wood of a tree trunk that no longer conducts sap. It is usually darker, denser and more decay-resistant than the outer wood, making it preferred for furniture and structural parts.

The outer, living layer of wood just beneath the bark that carries water and nutrients up the tree. It is lighter in colour, softer and more prone to insect attack and decay than heartwood.

The direction and arrangement of wood fibres along a piece. Straight grain splits and planes easily, while interlocked or wavy grain produces figure but is harder to work and more liable to tear-out.

The visible pattern on a finished wood surface created by grain direction, growth rings, rays or colour variation. Figure is a decorative quality valued in veneers and carved panels.

The controlled drying of timber to reduce its moisture content before use. Proper seasoning improves strength, stability and glue adhesion and reduces shrinkage, warping and fungal decay in the finished article.

The mass of water in a piece of wood expressed as a percentage of its oven-dry mass. It is measured with a moisture meter and determines shrinkage, movement and suitability for indoor or outdoor work.

The stable moisture level a piece of timber reaches when it exchanges water with the surrounding air until no further change occurs. It depends on air temperature and relative humidity at the site of use.

Drying timber in a heated, ventilated chamber where temperature, humidity and airflow are controlled by schedule. It is faster than air drying and can bring wood to a low, uniform moisture content.

Stacking sawn timber outdoors with spacers so that natural air movement slowly removes moisture. It is cheap but slow and can only reduce moisture content to roughly the local outdoor equilibrium level.

A seasoning defect in which the outer layers of timber dry and set while the core stays wet, leaving locked-in stresses. When re-sawn, the piece cups or springs because the stress is released.

A warp in which a board curves across its width, with the edges higher or lower than the centre. It results from uneven drying or from the different shrinkage of earlywood and latewood within growth rings.

A thin strip of dry wood placed between layers of stacked timber during air drying. Stickers keep boards apart so air can circulate and are aligned vertically to support the stack and limit warping.

Treating timber with chemicals or physical processes to protect it from insects, fungi, fire or weathering. Common methods include brushing, dipping, pressure impregnation and application of preservative oils or salts.

The larva of a beetle that tunnels through seasoned timber, leaving small round exit holes and fine dust. Infestation weakens the wood internally and is controlled by drying, preservatives and fumigation.

A social insect that eats wood and can destroy structural timber and furniture. Prevention includes keeping wood dry, avoiding contact with soil, using treated timber and regular inspection of buildings.

A hand saw with teeth filed to knife points that cut across the grain, severing fibres like a row of small blades. It is used for cutting timber to length and for rough sizing of boards.

A saw whose teeth are filed like small chisels to cut along the grain, clearing waste as it goes. It is used to convert wide boards into narrower strips and is recognised by its long, coarse teeth.

A short backsaw with a stiffened spine and fine teeth, used for accurate joinery cuts such as tenons and shoulders. Its rigid back keeps the blade straight during precise work.

The narrow slot of wood removed by a saw blade as it cuts. Kerf width depends on tooth set and blade thickness and must be allowed for when marking and cutting joints or dimensioning timber.

The slight sideways bending of saw teeth, alternating left and right, so the kerf is wider than the blade. Correct set prevents the blade from binding and allows waste to clear the cut.

Restoring a cutting edge on tools by grinding, honing and polishing. A sharp edge cuts cleanly with less force, is safer to control and reduces tear-out on wood surfaces.

An angled edge or surface that is not at a right angle to the faces of a piece. Bevels are used on chisels and plane irons for cutting geometry and on timber for decorative or fitting purposes.

A hand tool with a flat steel blade ground to a cutting edge and fitted with a handle. It is used for paring, chopping mortises and cleaning up joints; it must never be struck with a metal hammer.

A joint in which a projecting tongue, the tenon, fits into a rectangular socket, the mortise, cut in the other member. It is strong and is widely used in frames, furniture and traditional Assamese woodwork.

A corner joint made of interlocking wedge-shaped pins and tails that resist pulling apart. It is used for drawer boxes and carcasses where tensile strength across the corner is needed.

A cylindrical wooden pin used to align and strengthen joints, often with glue. Dowels replace some traditional joinery in modern furniture and are drilled to match corresponding holes in both parts.

A substance that bonds wood surfaces together by setting after application. Choice depends on moisture resistance, working time and clamping needs; common types are PVA, urea-formaldehyde and epoxy.

Holding glued or assembled parts under pressure with cramps or clamps until the joint sets. Adequate clamping closes gaps, spreads adhesive into a thin film and keeps parts aligned during curing.

A thin slice of wood cut from a log and glued onto a cheaper core or panel. Veneering allows decorative figure and rare species to be used economically while keeping the panel stable.

A sheet material made by gluing thin layers of veneer with the grain of each layer at right angles to the next. This cross-lamination gives balanced strength and reduces shrinkage and warping.

A material such as garnet, aluminium oxide or silicon carbide used to smooth wood surfaces. Abrasive grit number indicates particle size; lower numbers cut faster and higher numbers produce finer finishes.

Smoothing wood with progressively finer abrasives, working along the grain. It removes tool marks and raises a uniform surface for finishing, but over-sanding can round edges and burnish the wood.

Applying a protective and decorative coating such as oil, wax, lacquer or varnish to prepared wood. Finishing seals the surface, enhances figure and protects against moisture, dirt and wear.

Rough, splintered fibres left on a wood surface when a cutting edge lifts grain instead of severing it cleanly. It is reduced by sharp tools, light cuts and working with the grain direction.

A pictorial drawing in which the three axes are set 120 degrees apart and lengths are drawn to a single scale along them. It shows a three-dimensional view without perspective distortion.

A drawing method showing separate front, top and side views of an object projected onto planes at right angles. It gives true shapes and dimensions and is the basis of workshop working drawings.

A precise drawing giving dimensions, materials, joint details and notes needed to make an article. It must be complete enough that a craftsperson can build the item without further instructions.

A table listing every part of an article with its finished size, quantity, material and sometimes the rough size needed. It is prepared from the working drawing before timber is cut.

The allowance added to calculated timber quantities for saw kerf, planing, defects and offcuts. Ignoring wastage leads to shortfalls, so estimates add a percentage to the net measured volume.

Gear worn to protect the worker, such as safety glasses, dust mask, ear defenders and closed footwear. It is the last line of defence and supplements machine guards and safe working methods.

A wooden or plastic tool used to feed narrow stock past a saw blade or cutter while keeping hands at a safe distance. It must be replaced when worn or damaged.

The sudden violent ejection of a workpiece back towards the operator by a rotating blade or cutter. It is prevented by correct fences, guards, riving knives and steady, controlled feeding.