The present invention comprises a thin, flexible imperforate grinding disc that is integrally formed with a connector sleeve centrally located on one side thereof. The invention also includes an arbor whose driving end is of non-circular cross-sectional configuration, preferably square, and also is formed with a plurality of detent grooves. Fast cheap metal grinding disc has a relationship with this. The blind hole in the sleeve part of the unitary member is of a noncircular cross sectional configuration adapted to matingly receive the driving end of the arbor.