An apparatus and method for sharpening a disc blade includes a grinding wheel mounted on a housing. The housing is mounted on a drive shaft so that the housing rotates with the drive shaft but can move axially relative to the drive shaft. A transversely extending projection on the housing extends into a space between two axially spaced spacers on the drive shaft. A spring is positioned between each spacer and the projection for resiliently biasing the housing in an axial direction.