tearout

Tearout is the tearing or splintering of wood fibers that occurs when cutting, planing, routing, or drilling wood. It produces rough, uneven surfaces where fibers are torn away rather than cleanly planed or cut, and can complicate finishing. Tearout is more likely when working against the grain, on end grain, or with highly figured, dense, or brittle woods, and it is worsened by dull tools, aggressive cuts, or insufficient support for the workpiece.

Causes of tearout include grain direction (cutting across the grain tends to lift fibers), wood species and structure (softwoods and woods with interlocked grain tear out more easily), tool condition (dull or chipped cutting edges increase tearing), cutting parameters (depth of cut and feed rate), and lack of backing or proper support during machining. The phenomenon can occur in various operations, including planing, routing, chiseling, drilling, and slicing veneers.

Prevention focuses on technique and tooling. Use sharp, appropriate cutters and select tools suited to the wood type; plan or route with the grain when possible and provide adequate support behind the cut (such as a sacrificial backer or fence); take lighter passes or multiple shallow cuts to minimize fiber tearing; consider scoring or pre-cutting where appropriate. While some methods vary by tool and wood species, the general goal is to minimize the disturbance of fibers at the surface.

Repair and finishing options include light sanding to blend torn areas, filling with wood filler or sanding dust mixed with binder, or replacing the affected portion of the workpiece in severe cases. Tearout is a common quality concern in woodworking and is often addressed through technique, tooling, and stock selection.