Assam ASSEB HSLC Wood Craft flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Cambium layer

The thin layer of living cells between sapwood and inner bark that divides to produce new wood cells inward and new bark cells outward, making it the only growth layer in a tree.

Heartwood versus sapwood

Heartwood is the inner, darker, non-conducting wood that is usually more durable and resistant to decay; sapwood is the outer, lighter, living wood that conducts water and takes preservative more readily.

Fibre saturation point

The moisture content at which all free water has left the cell cavities but the cell walls remain fully saturated, about 28 to 30 percent; above this point wood does not swell further.

Anisotropic shrinkage

Wood shrinks and swells unequally in three directions, most tangentially, less radially and least along the grain, which is why flat-sawn boards cup and check during drying.

Reaction wood

Abnormal wood formed in leaning stems: compression wood on the lower side of softwoods and tension wood on the upper side of hardwoods; both cause distortion and machining problems when dried.

Rip saw versus crosscut saw

A rip saw has coarse teeth filed to cut along the grain, while a crosscut saw has finer bevel-edged teeth that sever fibres across the grain for a cleaner end cut.

Purpose of saw set

Saw set is the alternating lateral offset given to the teeth so the kerf is wider than the blade, preventing the blade from binding and allowing it to clear sawdust.

Frog adjustment

The frog carries the plane iron and cap iron; moving it forward closes the mouth for fine work on hard or curly timber, while a wider mouth suits soft wood and thick shavings.

Chisel bevel angle

A wood chisel is usually ground to about 25 degrees with a 30 degree honing micro-bevel; harder wood and chopping work favour the steeper angle, paring favours the lower.

Marking gauge

A tool with a pin or knife set in a stock that slides on a beam; it scribes a line parallel to a face or edge, and a mortise gauge carries two pins set to the chisel width.

Mortise and tenon proportions

In a standard mortise and tenon, the mortise width equals the chisel width, the tenon thickness is about one-third of the rail thickness, and a haunch fills the groove end.

Through versus lapped dovetail

A through dovetail shows tails and pins on both faces and suits boxes; a lapped dovetail hides the end grain on one face and is used for drawer fronts.

Housing joint

A groove cut across the grain of one member to receive the end or edge of another; a stopped housing does not run out through the visible edge.

Dowel sizing rule

Dowel diameter is about one-third of the stock thickness and each hole is about half the dowel length deep; glue grooves let trapped air and excess glue escape.

Air seasoning method

Timber is stacked on a level base with stickers between courses for air circulation, under cover and out of sun, with ends sealed; it takes roughly a year per 25 mm of thickness.

Equilibrium moisture content

The moisture content at which wood neither gains nor loses water to the surrounding air; it depends on relative humidity and temperature and in humid Assam is often 12 to 15 percent.

Case-hardening in timber

A drying defect in which the outer layers dry and set while the core is still wet, leaving locked-in stresses that show as immediate spring-back when the board is resawn.

Boron preservative

A water-borne preservative of borax and boric acid that diffuses into green timber, gives good protection against insects and decay indoors, but leaches out where exposed to rain.

French polish

A high-gloss finish built up by applying shellac dissolved in alcohol with a rubber pad in many thin coats, giving a deep reflective surface on fine furniture.

PVA versus resorcinol glue

PVA is a white interior adhesive with good strength but poor water resistance; resorcinol-formaldehyde is a dark exterior adhesive that withstands moisture and boiling water.

Wood filler colour choice

Filler should match the colour of the finished, stained wood rather than the raw timber, because the stain darkens the surrounding wood and the filler would otherwise stand out.

Sanding grit sequence

Work through progressively finer abrasives, for example 80, 120, 180 and 240 grit, always along the grain, removing dust between grits and never skipping a grit.

Isometric drawing

A pictorial drawing in which three axes meet at 120 degrees and true lengths are measured along each; it shows three faces at once without perspective distortion.

Bill of materials

A schedule listing every part of a project with its finished size, quantity and species, plus a wastage allowance, used to order timber and estimate cost.

Timber volume in cubic feet

Volume equals length times width times thickness in feet for one piece, multiplied by the number of pieces; convert millimetres to feet by dividing by 304.8.

Third-angle projection

A drawing convention in which the plan is placed above the elevation and the side view to the side it is viewed from; first-angle places the plan below instead.

Sal timber

Shorea robusta, a durable hardwood common in Assam, used for structural timber, railway sleepers, doors and furniture; hard, heavy and resistant to decay and termites.

Gamari timber

Gmelina arborea, a fast-growing plantation hardwood widely grown in Assam; light, easy to work, used for furniture, plywood, carving and general joinery.

Assam bamboo and cane craft

Bamboo and cane are woven into baskets, mats, sieves, fish traps and furniture across Assam; the craft uses locally abundant, fast-renewing material and is a major handicraft.

Satra wood carving

Vaishnavite monasteries of Assam, the satras, carry carved doorways, columns and thrones with floral and geometric motifs, a living tradition of regional wood carving.

Circular saw safety devices

A circular saw must have a blade guard, a riving knife that prevents the kerf closing on the blade, and a push stick to keep hands clear of the teeth.

Squareness check

A carcass is checked for square by measuring both diagonals; equal diagonals mean the frame is square, and any difference is corrected before glue sets.