Pancyprian TS Wood & Furniture III key terms

The mass of water held in a piece of timber, expressed as a percentage of its oven-dry mass. It governs shrinkage, swelling, gluing success and dimensional stability of finished furniture.

The moisture level at roughly 28–30% at which cell walls are fully saturated but free water has left the cavities. Above it timber does not shrink; below it movement begins.

The stable moisture level timber reaches when it exchanges water vapour with the surrounding air until neither gains nor loses moisture. It depends on air temperature and relative humidity in the workshop or room.

Controlled drying of stacked timber in a heated chamber where temperature, humidity and airflow follow a schedule. It brings moisture down quickly to a target level while limiting checking, case hardening and collapse.

A drying defect where the outer shell of a board dries and sets while the core stays wet, leaving locked-in stresses. When resawn, the board cups or splits because the stress is released.

Distortion in which a board's cross-section curves across its width, concave on one face and convex on the other. It results from unequal moisture loss between the two faces or from tension wood.

Contraction of timber measured along the growth rings as it dries. It is roughly twice radial shrinkage, which is why flat-sawn boards move more in width than quarter-sawn ones.

Boards cut so the growth rings meet the wide face at a steep angle, giving narrow growth-ring stripes. It shrinks less in width, resists cupping and shows attractive figure such as ray fleck in oak.

Contraction of timber measured across the growth rings, from pith towards bark. It is smaller than tangential shrinkage, so quarter-sawn stock stays flatter and holds its width better.

A separation between growth layers, running along the grain, often near the pith or at a ring boundary. It weakens the piece and may open visibly after machining or drying.

A section of branch embedded in the trunk where grain direction changes sharply around it. Dead knots loosen and drop out; live knots are sound but harder to work and can blunt edges.

The predominant alignment of wood fibres along a piece. Planing, jointing and sanding with the grain gives clean surfaces; working against it tears the fibres and raises fuzz.

An engineered panel of fine wood fibres bonded with resin and pressed to a uniform density. It machines and finishes smoothly with no grain, but swells badly when wet and holds screws poorly at edges.

A panel made from wood chips and resin pressed into a sheet. It is cheap and flat but weak at edges and vulnerable to moisture, so it is normally faced with veneer or laminate and edge-banded.

A drawing method showing a three-dimensional object as separate flat views, usually front, plan and side, arranged on one sheet. First-angle and third-angle arrangements place the views differently.

A layout where each view is placed on the side of the object from which it is seen, with the plan above the front view. It is the standard arrangement in many workshop drawings and uses the truncated-cone symbol.

A drawing that imagines the object cut by a plane and shows the exposed interior, with cut material hatched. It reveals hidden construction such as joints, mortises and internal fittings.

A table listing every component of a job with its finished sizes, quantity, material and grain direction. It drives timber ordering, machining set-ups and assembly sequence in the workshop.

A drawing in which all dimensions are reduced or enlarged by a stated ratio, such as 1:5 or 1:10. It allows full-size checking of proportions and joint details before cutting timber.

Rough, splintered fibres left where a cutter exits the wood, common when planing or routing against the grain or at the end of a board. A backing piece or climb-cut strategy reduces it.

A violent throw-back of the workpiece towards the operator when a saw blade or cutter grabs the timber. It is prevented by correct riving knife and guard settings, sharp teeth and steady feed.

A shaped wooden or plastic aid used to feed narrow or short stock past a blade or cutter while keeping hands clear. It is mandatory practice on circular saws, spindle moulders and planers.

A fixed plate mounted directly behind a circular saw blade, following its curve, that stops the kerf closing and pinching the blade. It must be aligned and set close to the blade for effective protection.

Setting infeed and outfeed tables or fences so they are flat, parallel and coplanar within tolerance. Poor alignment causes snipe, tapered cuts and inaccurate jointing even with sharp cutters.

A shallow dip cut at the start or end of a board passed through a planer or thicknesser, caused by the workpiece tipping as it leaves or enters the cutter or by misaligned tables.

Positioning and locking the guide fence of a saw, router table or spindle moulder at the required distance and angle. The fence must be parallel to the blade or cutter and rigid under load.

The combination of hood, pressure pads, hold-downs and ring guard that encloses the cutter block on a spindle moulder. Correct setting keeps hands away from the tool and controls the workpiece.

A joint where a projecting tongue (tenon) on one member fits a matching rectangular cavity (mortise) in another. It is strong in both compression and racking and is the backbone of frame construction.

A small extra extension on a tenon, or a short shoulder, that fills the end of the mortise and resists twisting. It also increases gluing area and stiffens the joint under racking loads.

A square-ended groove cut across a member to receive the end or edge of another, as in shelving and drawer runners. It gives a strong, self-locating seat and is often combined with a screw or dowel.

Two or more cylindrical wooden pins glued into matching bored holes to align and strengthen a butt or edge joint. Accurate hole spacing and depth control decide the joint's strength and squareness.

The order in which successively finer abrasive grades are used, for example 80, 120 then 180, each removing the scratches of the previous one. Skipping a grade leaves marks that show under finish.

The lifting of wood fibres that occurs when water-based liquid touches the surface, leaving it rough after drying. Damping and lightly sanding before finishing prevents a fuzzy final coat.

A fast-drying coat applied before the main finish to stiffen surface fibres so they sand off cleanly. It reduces absorption differences, builds a smooth base and lowers the number of topcoats needed.

The maximum period after adhesive is spread during which parts may still be brought together and positioned before the glue starts to set or skin over. It falls as workshop temperature rises.

The force applied to hold glued parts together until the adhesive cures. Too little leaves gaps and weak glue lines; too much squeezes out adhesive and starves the joint.

Setting the work surface so the operator's forearms are roughly level and the back stays straight for the task. Precision work sits higher, heavy planing lower, to reduce fatigue and strain.

A dust extraction system that captures chips and fine dust at the machine hood before it reaches the operator's breathing zone. Duct size, airflow and filter condition determine its effectiveness.

The maximum permitted airborne concentration of wood dust over a working period, set because hardwood dust is a recognised carcinogen. Compliance requires extraction, housekeeping and sometimes respiratory protection.

Items worn by the operator such as safety glasses, hearing protection, dust mask and safety footwear. It is the last line of defence, used after guarding, extraction and other controls are in place.

The permitted range of variation around a nominal dimension within which a component is accepted. Realistic tolerances reflect machine capability and joint design without wasting time on unnecessary precision.

Checking components and finished furniture against specification at defined stages, such as after machining and before packing. Records of measured results allow faults to be traced and corrected.

An itemised schedule of materials, hardware and labour needed for a job, with quantities and unit costs. Multiplied out, it gives the estimate used to price the work and order stock.