Kerf

Kerf is the width of the slot a saw blade leaves behind as it cuts — the "width of the cut" itself, not just how thick the blade looks sitting still. A typical table saw blade runs a kerf between 1/8" (3.2mm) for full-kerf and around 3/32" (2.4mm) for thin-kerf.

Why It Matters

Kerf matters the moment your cuts need to add up to something specific. Forget to account for it across several cuts from one board and your final piece comes up short — every cut quietly confiscates a sliver of material that ends up in neither resulting piece, like a small toll booth your board didn't know it was driving through.

This is especially important for joinery like box joints and dovetails, where the joint's fit depends on the kerf matching the spacing of the pins and tails, and for the Plywood Sheet Optimizer-style cutlist planning, where kerf has to be subtracted between every cut on a sheet.

Thin-Kerf vs. Full-Kerf Blades

Thin-kerf blades remove less material per cut, which means less waste and less resistance for underpowered saws, but they can be more prone to flexing or wandering in very hard or thick stock. Full-kerf blades tend to run more stably but waste more material and demand more power from the saw's motor.