Abstract: An attachment for use with a high speed mini-grinder which helps persons laying tile to undercut baseboards and door trim adjacent to a tiled surface for insertion thereunder of the edge of each perimeter tile so as to eliminate grout lines which would otherwise be required around the edge of the tiled surface. The attachment comprises a cutting blade with negative hook, an outwardly biased telescoping blade guard to cover the cutting blade at all times except when in use, a frame that is vertically adjustable for making cuts of different heights to accommodate tiles of different thickness, countersunk screws to connect the cutting blade to mounting bracket attached to the mini-grinder, and an adjustable depth stop for setting the maximum depth of the cut made into a baseboard or door trim. Applications may include, but are not limited to, use in cutting door trim including door jambs, door casings, and door stops, as well as base molding preparatory to the laying of floor tile.