The grindstone is still employed for sharpening metal-cutting tools, but it has been in a great measure displaced by emery or carborundum grinding wheels.

Many types of tool-grinding machines are now common among machine-shop equipment. One of the smallest consists of an encased electric motor whose shaft carries a small grinding wheel on each end, with adjustable rests at the side and edge of each wheel for steadying work held in the hand. This small machine is usually mounted on a bench.

Another type much used is the heavy wheel, motor driven, mounted on a closed base and partly covered by a hood.

A machine shop sometimes has machines other than tool-grinding machines especially designed and built for very accurate circular or flat grinding, but this degree of accuracy is not required in the usual run of machine-shop work.