Woodworking terms glossary

Board foot (BF)

A volume equal to 144 cubic inches, traditionally represented by a board 1 inch thick, 12 inches wide, and 12 inches long. In imperial units, board feet = thickness in inches × width in inches × length in feet ÷ 12. Use the Board Foot Calculator for mixed sizes and quantities.

Square foot

A measure of area equal to a 12-by-12-inch surface. It does not include thickness. A square foot of 1-inch material contains one board foot; the same area at 2 inches thick contains two board feet.

4/4, 5/4, 6/4, and 8/4

Quarter-inch rough hardwood thickness categories. Four-quarter is nominally 1 inch, five-quarter is 1.25 inches, six-quarter is 1.5 inches, and eight-quarter is 2 inches before final surfacing. Actual finished yield varies. See the Hardwood Thickness Guide.

Rough lumber

Wood that has not been fully surfaced to flat, parallel faces and straight edges. Rough dimensions may be used for hardwood billing, while finished parts are smaller after milling.

Nominal dimension

A trade size or product name rather than an exact current measurement. A nominal 2×4 commonly measures about 1.5 by 3.5 inches after surfacing. Read Rough vs. Actual Lumber Dimensions.

Actual dimension

The physical measurement of a board or part at the time it is measured. Actual size controls joinery and fit, but it may not be the dimension a supplier uses to tally rough hardwood.

S2S, S3S, and S4S

Common surfacing descriptions. S2S generally means two faces surfaced; S3S adds one straight edge; S4S means both faces and both edges are surfaced. Exact seller practices and tolerances can vary.

Waste factor

An allowance added to theoretical material needs for defects, cutting geometry, kerf, milling loss, test pieces, and selection. It is not a universal percentage. See the Lumber Waste Factor Guide.

Kerf

The material removed by a saw cut. Blade tooth geometry, setup, and cut quality determine actual kerf. A cutting diagram must reserve this width between neighboring parts.

Yield

The useful parts or material obtained from purchased stock. Yield depends on board dimensions, defects, grain requirements, milling, moisture, and cut-list geometry—not only total volume.

Clear gap

The open distance from the edge of one item to the edge of the next. The equal-spacing and board-and-batten calculators report clear gaps separately from on-center spacing.

On-center (OC) spacing

The distance from the centerline of one repeated item to the centerline of the next. When item widths are equal, on-center spacing equals one clear gap plus one item width.

Flush-end layout

A repeated layout in which the first item begins at one boundary and the last item finishes at the other. The remaining space is divided by one fewer than the item count. Explore it with the Equal Spacing Calculator.

Equal outer gaps

A centered layout where the open space at both ends equals every interior gap. The remaining space is divided by one more than the item count.

Overlay door

A cabinet door that covers part of the face frame or frameless cabinet edge. Door size is generally the opening size plus overlay at both opposing edges. Hinge specifications control valid overlay.

Inset door

A cabinet door fitted within the opening. Its finished size is the opening minus clearances at the edges. Opening squareness and seasonal wood movement are especially important.

Reveal

The visible gap or exposed margin around or between cabinet doors and drawer fronts. In a paired-door calculation, the center reveal is subtracted before the covered width is divided between the doors.

Rail and stile

Frame components used in a frame-and-panel door. Stiles normally run vertically for the full door height; rails run horizontally between them. Joinery style determines rail cut length.

Cope-and-stick

A rail-and-stile joinery system where a shaped rail end mates with a matching stile profile. Groove depth and cutter geometry affect both rail length and center-panel size.

Center panel

The panel captured by the rails and stiles of a frame-and-panel door. Plywood and MDF are relatively stable; solid wood needs appropriate room to move across the grain.

Side clearance

The space required between a drawer box and its mounting surfaces for slide hardware. Some specifications state clearance per side; others state total clearance or use a model-specific formula.

Applied bottom

A drawer bottom attached beneath the box rather than inserted into grooves. Its setback can hide the edge or suit the fastening method, but it must remain compatible with the slide system.

Captured bottom

A drawer bottom fitted into grooves in the box parts. Panel dimensions include groove engagement. Actual groove and panel thickness should be tested before cutting a batch.

Groove depth

The distance a panel or tongue enters a mating groove. It is not always the same as the cutter's advertised radius or nominal profile size; verify a test joint.

Face frame

A frame attached to the front of a cabinet box. Its opening can differ from the interior slide spacing, so drawer measurements must follow the hardware mounting surfaces.

Frameless cabinet

A cabinet construction without a separate front face frame. Doors and slides typically reference the cabinet sides, but edge banding, fillers, and hardware plates still affect final dimensions.

Racking and square

Racking is distortion that turns a rectangle into a parallelogram. Compare diagonals to check square: equal diagonals indicate a rectangular assembly when opposing sides are equal. A perfectly sized door or drawer can still bind in a racked opening.

Wood movement

Dimensional change caused by moisture variation, primarily across the grain. Construction must allow solid-wood panels, doors, and wide parts to expand and contract without splitting or binding.