Abstract: A toolholder for use in shaping the blade of a screwdriver with a grinder having a grinding wheel and a guiding surface parallel to the axis of the wheel, the toolholder including a pair of blocks adapted to clamp the shank of the screwdriver between them, each block providing a guiding surface angularly related to the shank and disposed oppositely of the other block; clamps spaced along the axis to draw the block onto the shank and selectively adjustable to bring the guided surfaces into normal relation with a plane normal to the axis; and a pair of projections on the blocks bearing indicia indicating the relative spacing of their ends when the guided surfaces are in such normal relation, the toolholder being guided by engagement of one of the guided surfaces with the guiding surface to shape one side of the blade and being invertible with the screwdriver for guidance of the toolholder by engagement of the other of the guided surfaces by the guiding surface to shape the other side of the blade.