Tearout

Tearout is what happens when a cutting edge — a plane iron, router bit, saw blade, drill bit, doesn't discriminate — catches wood fibers and rips them out rather than shearing them clean. It shows up most reliably when you cut against the grain, work figured or curly stock, or reach for a tool that's overdue for sharpening.

Common Causes

• Cutting against the grain — see Grain for how fiber direction affects this.
• Dull cutting edges — a sharp edge shears fibers; a dull one tends to tear and push them instead.
• Too aggressive a cut — a heavy pass with a hand plane or a fast feed rate with a router increases the chance of lifting fibers before they can be sheared cleanly.
• Exit-side blowout — on through-cuts (drilling, routing, table saw cuts), fibers on the far side of the workpiece often have no support left underneath them and can chip out as the cutter exits.

How to Reduce It

• Take lighter cuts, especially in figured or reversing-grain stock.
• Keep tools sharp — this is consistently the single biggest factor.
• Use a backer board or sacrificial scrap behind the workpiece to support fibers on the exit side of a cut.
• On table saws and routers, a zero-clearance insert or baseplate reduces support-related blowout right at the cut line.
• For hand tools, a tighter mouth opening (on a hand plane) or a higher cutting angle can help tame reversing or figured grain.