Abstract: A brush holder mechanism for electric motors, especially the fractional horsepower commutator-equipped motors of workshop power tools. In order to prevent failure of the tool due to jamming of the carbon brushes in their holders, the brush holder according to the invention provides that the brush holder casing in which the carbon brush moves has smooth, flat and uninterrupted interior surfaces and the casing is constructed of a single piece of metal or a single piece of metal on which a continuous cover plate is attached. The integral construction of the casing insures that the casing is not deformed during manufacture or assembly, in particular by the bending of parts of the casing into fastening tabs and the like. In the brush holder according to the invention, the fastening means are integral with the cover plate or the casing. In other embodiments, the casing is held in a receiver by clamps and screws.