What is a Kerf?

A kerf refers to the groove or slit made by the blade of a cutting tool, most commonly a saw blade, as it cuts through a piece of material. More specifically, the word can refer to the width of this cut. This measurement is usually printed on saw blade packaging or on the saw blade itself. In the case of a saw, the kerf is always wider than the blade itself, because the saw's teeth flare somewhat in order to be able to work their way through various materials. Different kinds of blades produce cuts of different widths, and it is important to be aware of this when working on a project, because the amount of material removed by the blade affects the accuracy of measurements made.

For saws, one can choose a thin kerf blade or a wide kerf blade. Each has advantages and disadvantages and is suited to different materials and kinds of projects. Blades producing wider cuts are stronger and more resilient. They can withstand repeated sharpening better than the narrower cutting blades and can make deeper cuts in thicker materials. Table saws usually have a wider kerf saw blade because they are made to be strong and versatile enough for both cutting across the grain and cutting with the grain.

A thinner kerf makes a smoother cut, producing less sawdust and noise. Less sanding of the cut surfaces is usually required because of the smoothness of the cut. One common use for thin kerf blades is for cutting materials that tend to splinter and chip, for example, particle board, plywood, and laminate. The smoother cuts produced by these blades are preferable for these materials.

Hand-held circular saws commonly have blades that make narrower cuts than table saws. Blades making narrower cuts use less energy to cut through material, making these blades more suitable for hand-held saws than the wider cutting blades used by more powerful, stationary table saws. Very narrow cuts can be made with an ultra thin kerf saw blade, which can produce a cut about the width of a dime. It is important to allow for the width of the cut when working on a project, otherwise measurements made will not be accurate. The best way to do this is to first cut a test piece to see how much material is removed on either side of the cut and allow for this when taking measurements.