Woodworking Definition: Kerf

Close up detail of circular saw
Cultura/James Shilton Getty Images

The term  KERF is used to describe the thickness of the cut a woodworking saw blade makes in the stock it is cutting. It is also sometimes used to describe the thickness of the blade itself; you may see the packaging of a circular saw blade or table saw blade listing its kerf width

Factors Determining Width of a Kerf

The kerf (the width of a saw cut) is determined by the width of the blade itself, by the "set" of the teeth (the angle away from vertical by which the teeth are attached to the blade), and the wobble of the blade.

Coarse construction blades often have heavy carbide teeth welded onto a stainless steel blade with a pronounced angled set that allows for quick but rough cutting. These are normally used for framing carpentry work. 

For fine woodworking, thinner blades with many teeth with little or no angled set to the teeth. Often the teeth are not added onto the blade but are integrally shaped into the metal of the blade itself. This makes for a very smooth cut, and an economical cut--since little wood is wasted through wide saw kerfs. This can be a notable factor when working with very expensive woods. 

A saw blade out of alignment will wobble while cutting, and this can increase the width of the kerf by a notable amount. For efficiency of cutting and economical use of wood, always make sure your saw blades are properly aligned.