A grinding tool is a basic hand or stationary tool that uses an abrasive to form or sharpen materials. In some cases, the same physical tool may be used to smooth material and would be called a sanding tool, although there are devices used only for shaping or for smoothing.
The most basic grinding tool is a block of abrasive against which the work is rubbed. Alternatively, the stone may be equipped with a handle and rubbed across the work. Stones can also be used, with due regard to safety, on work rotating in a lathe.
Hones for knife sharpening may either use a bonded abrasive, such as carborundum or diamond, or may be made of metal harder than that of the knife. Hones are typically used late in the sharpening process, as much to straighten the edge as to reform it.
There is a very wide range of handheld power tools that spin an abrasive stone or disk to be applied to the work. The smallest resemble dental drills, and can be used for very fine detail; they are often called Dremel tools after a major manufacturer. These tools may also be mounted in router, drill press, or other bases.
Higher-capacity tools have considerable torque and can quickly remove metal.
A common shop tool is the bench grinder, the most common type of which has a horizontal axle, with a motor in the center, with grinding wheels mounted at either end of the axle. The work is sometimes simply handheld, but there is commonly at least a rest for the work, and there may be a precision holder so a piece can be ground at a specific angle (e.g., for sharpening twist drill bits).