A chisel is a cutting tool, with the most common types used for wood, and specialized forms with uses in metalworking and masonry. The simplest form is a flat, fairly thick piece of steel, with one end ground into a cutting edge. There is only one sharp edge on a woodworking chisel; the back is perfectly flat. Metal and brick chisels may have two edges.
At the other end may be a wooden or plastic handle, or, in some cases, a flat metal surface. For most woodworking uses, energy is applied, with a soft-faced hammer (i.e., mallet), to the end opposite the edge, although the chisel may be pushed by hand for some delicate work. Some chisels are intended to be pressed against material spinning in a lathe, and thus need only enough pressure to guide them.
There are relatively few directly powered equivalents to chisels, at least in woodworking. A router (tool) often is used for similar work with less effort and often greater precision.
Power chisels, however, are used on metal and masonry.
Categorizing wood chisels
Wood chisels are grouped by the intensity of work, the length of the blade, the shape of the cutting edge and the shape of the blade.
The lightest-duty chisels, which are either guided by hand or by gentle tapping with a light hammer, are called paring chisels. Medium-duty wood chisels are called firmer chisels, while those intended for the heaviest work are called mortise or framing chisels. In general, the angle of the bevel of the cutting edge is shallowest, perhaps 15 degrees, on a paring chisel, and up to 25 degrees on framing chisels.
Chisels need to be kept sharp, but proper sharpening takes considerable skill.
Woodworking chisels typically have a blade between 2 and 4 inches wide, although they can be quite narrow. Any blade wider than 2 inches is termed a slick, and intended for shallow removal of material. Note that a [[plane (tool)] is, in many respects, a chisel inside a more controllable mount, and may be appropriate for removing large amounts of material.
Blades are usually flat, but can be curved, and are then called gouge chisels or simply gouges.
Short clisels, less than 3 1/4 inches, are called butt; chisels between 5 and 6 inches are pocket, while those 8 to 10 inches are mill chisels.