Abstract: A device for abrading and finishing excess cured filler material from a bullnose outside cornerbead connected between immediately adjacent sheets of drywall. The device includes an elongated rigid body having a generally concave-shaped central longitudinal portion which preferably replaceably receives a sheet of somewhat compressible open fibrous adhesive material which is preferably substantially coextensive with, and arcuately formed to match the bullnose cornerbead convex contour, by the central longitudinal portion. In the preferred embodiment, a guide rail extends along either longitudinal margin of the central longitudinal portion which, in cooperation with the abrasive layer mateingly engaged against the bullnose cornerbead, substantially match the outside angle between the adjacent drywall sheets.