Accessory support plates for a magnet base drill

In combination, a portable drill unit having an electromagnetic base for magnetically adhering the drill to a magnetic support, said base having a bottom wall and a pair of opposite side walls, a pair of plates formed of magnetic material, means for mounting said plates on the side walls of said base for vertical adjustment thereon, said plates having lower edge portions and being adjustable on said base so that said lower edge portions project downwardly below said bottom wall of said base, and means for rendering at least the central portion of said bottom wall and said plates magnetic when the electromagnet is energized, whereby, when said base is mounted on a convex magnetic support surface, said plates can be extended downwardly to a position wherein the lower edge portions thereof engage portions of said support surface at locations spaced laterally outwardly on opposite sides from the central portion of said base to thereby magnetically adhere the drill on said support in a stable position when the electromagnet is energized.