side

In timber manufacturing, to side a piece of wood means to machine its edges and faces flat and parallel to a target thickness or width. This is distinct from edging, which narrows the stock along the grain. Siding removes material from the sides of a board or rib, the long faces running the length of the grain, using a planer, moulder, or similar face machinery. The goal is to produce stock of consistent cross-section suitable for furniture, structural work, or further processing.

The operation typically follows initial roughing or breakdown. A log or cant passes through a bandsaw or circular saw to yield rough boards of approximate width. These rough boards then move to a four-square moulder or thickness planer where all four faces are worked in sequence. The infeed and outfeed rollers apply pressure while the cutterhead removes shavings, usually between 2 and 6 millimetres per pass, until the board reaches target dimensions. Hardwoods and kiln-dried softwoods respond differently; moisture content below 20 percent improves surface finish and reduces tearout.

Why side matters in the workflow

Inconsistent sided stock causes problems downstream. Furniture makers cannot produce uniform joints if rails or stiles vary in thickness by even a few hundredths of an inch. Structural timbers that are not squared waste material and compromise load capacity. Siding also removes surface defects like saw marks and bark remnants, revealing the true quality of the wood beneath. This is why many mills side to both a target thickness and width, producing what is called four-square stock.

The term comes directly from the geometry: you are working the sides (faces) of the timber, as opposed to the ends or edges. In historical hand-tool practice, a woodworker would use a jointer plane or jack plane to true the sides of a beam or board to consistent thickness. Modern mills have automated this with powered machinery, but the vocabulary persists. Related terms include facing, which works one face flat, and edging, which machines the narrower edges.

Common defects in siding include chipping and tearout when grain runs unfavorably, snipe (a shallow gouge at the board's end as it leaves the moulder), and wavy surfaces if the infeed rollers are worn or misaligned. Temperature swings in the workshop can cause boards to cup or twist after siding, so moisture management is essential. Mills that side to very tight tolerances, such as plus or minus 1/32 inch, typically use double-sided or four-square moulders with servo-controlled feed systems.