It is the amount of material, chip width, taken out of a piece of material that is being machined usually associated with a saw, though other tools will have kerf. In a saw it is determine by the type of saw teeth , the pitch, and set of the teeth.
The origin of the word is English according to the Woodright on Public TV.
Also how good the machine is. Kerf is used interchangeably (and technically incorrectly) with the width of the tool. A wobbly saw blade has the same width but a larger kerf.
Kerf loss is why you can’t cut two 4 foot pieces out of an 8 foot sheet. Take 0.150” out of the middle for the width of the cut (kerf.)
Incidentally a reduction in kerf of 0.003” can be worth $50,000 a year to a big saw mill.
The term kerf is also applied to various flame cutting processes such as laser, plasma, or oxy-fuel cutting. Along with the kerf of a cut there is also bevel which is taper generated by the process. Bevel is very apparent in plasma cutting. Some people use the term kerf incorrectly as a replacement for bevel.
