SOLAS Wood Manufacturing & Finishing key terms

The orientation of wood fibers along the length of a board. Cuts, planing, and sanding follow it to avoid tear-out, and fasteners or joints are usually aligned with it for strength.

Rough, splintered fibers pulled from a surface when a cutter works against the grain. It is reduced by cutting with the grain, using sharp tooling, and taking lighter passes.

Loss of material at the exit edge of a cut, common when drilling or routing across grain. A backer board or reduced feed rate at the exit side limits it.

A condition where wood fibers run out near the end of a part, leaving little lengthwise strength. It causes weak joints and breakage and should be avoided when laying out components.

Splitting wood along the grain, deliberately or accidentally. In hand work it is used to produce thin stock; in service it describes a failure where a fastener or load splits the member lengthwise.

The gradual emergence of grain fibers at a surface because the board was sawn at a slight angle to the true grain. It makes planing and sanding difficult and weakens thin parts.

A routing or machining pass where cutter rotation matches the feed direction, pulling the work into the tool. It gives cleaner edges on some materials but demands rigid setups and controlled feed.

A sacrificial piece clamped behind or beneath the work to support fibers at the exit of a cut. It prevents chip-out when drilling or routing through a component.

The width of material removed by a saw blade or cutter. It must be allowed for in cut lists and layout, and it determines whether offcuts remain usable for narrow parts.

A schedule of every component with its dimensions, quantity, material, and grain orientation. It drives stock selection and cutting sequence and is checked against the drawing before machining begins.

The mass of water in wood expressed as a percentage of its oven-dry mass. It governs shrinkage, swelling, gluing, and finishing, so stock is conditioned to the service environment before assembly.

The moisture level wood settles at when held in air of a given temperature and relative humidity. It predicts whether a finished part will shrink or swell in its final location.

Controlled drying of lumber in a heated, humidified chamber following a schedule. It reaches a target moisture content faster than air drying and relieves stresses when the schedule is correct.

A drying defect where the outer shell of lumber is set in tension while the core is in compression. Boards may cup or split when resawn, and stress relief is needed before machining.

Dimensional change in wood as moisture content rises or falls, greatest across the width and least along the length. Design allows for it through panel orientation, slotted fasteners, and floating tops.

A warp where a board's edges rise or fall relative to its center because one face absorbs or loses moisture faster than the other. It is corrected by jointing or avoided by even drying and sealing.

A construction where a solid panel floats in grooves in a surrounding frame. The grooves allow seasonal movement while the frame holds the panel flat and hides its edges.

A panel with beveled or shaped edges that sit in a frame's groove, giving a decorative fielded face. The bevel is machined before assembly and the panel is left free to move.

The vertical (stile) and horizontal (rail) members of a framed door or panel assembly. Their joints, usually mortise-and-tenon or cope-and-stick, locate the floating panel.

A joint where a projecting tenon on one member fits a matching cavity, the mortise, in another. Glue faces on the tenon cheeks and shoulders give strong resistance to racking.

A flat-bottomed groove cut across the grain, usually to house a shelf or panel. Its width is matched to the mating part and its depth leaves enough material for strength.

A step or shoulder cut along the edge of a member, also called a rabbet. It is used to house a back panel or to form an overlapping joint, and is cut with a router or dado set.

Assembling joints and components without adhesive to check fit, square, and alignment. Problems are corrected before glue is applied, when adjustments are still easy and clean.

The planned order in which parts are joined, working from the inside out. It prevents trapping subassemblies and ensures clamping access and square checking at each stage.

The particle size designation of coated abrasive, where lower numbers cut coarser and higher numbers polish finer. Sanding progresses through grits to remove scratches from the previous step.

The ordered progression of grits used on a surface, each removing the scratches left by the previous one. Skipping grits leaves deep marks that show through thin finishes.

Polishing wood or finish by friction heat or very fine abrasive, producing a sheen. Over-burnishing before staining can seal the surface and cause uneven color take-up.

A thin coating applied before finish coats to limit absorption and raise grain for sanding. It evens stain take-up and can improve adhesion between incompatible coats.

A fast-drying sealer formulated to be sanded easily after it stiffens the surface fibers. It is used to build a smooth base before topcoats, not as a durable finish itself.

A pigmented or dye-based product that changes wood color without forming a thick film. Even application and controlled wet time prevent lap marks and blotching on absorbent species.

Uneven stain absorption that leaves patchy dark and light areas, common on open-pored species. A washcoat or gel stain slows absorption and evens the color.

A very thin coat of sealer applied before staining to partially seal porous areas. It reduces blotching and controls how deeply pigment penetrates the surface.

The final protective layer of finish exposed to wear and moisture. It is chosen for durability and sheen and applied over compatible sealer or build coats.

A liquid's resistance to flow, which determines how a finish sprays, brushes, or levels. It is adjusted with thinner or by temperature and measured with a flow cup.

Atomized finish that misses the workpiece and dries as dust on surrounding surfaces. It causes gritty texture if it lands on wet coats and is controlled by spray technique and booth airflow.

A stippled surface texture resembling citrus skin, caused by finish failing to flow out. High viscosity, low pressure, or excessive air movement are common causes.

The interval allowed between coats for solvent to evaporate before the next application. Too short an interval traps solvent and causes blushing, runs, or poor adhesion.

A milky white haze in a clear finish caused by moisture trapped as solvent evaporates quickly. High humidity, cold surfaces, or short flash-off promote it.