a disposable cut - off wheel for mounting on a rotatable threaded spindle which may be used with a power tool . the cut - off wheel includes a central aperture which contains a threaded nut having a flange at one end non - removably secured thereto without the aid of adhesives in such a manner that the cut - off wheel is placed in compression when it is operably secured upon the spindle under operational loads . the nut is secured to the cut - off wheel by upsetting one end of the nut causing it to protrude outwardly over the rear surface of the cut - off wheel or into engagement with the aperture . a generally inverted cup shaped supporting flange is carried by the spindle for engaging the outer surface of the cut - off wheel during operation of the cut - off wheel . a plastic washer like insert member is received within and carried by the supporting flange and provides a bearing between the lip of the supporting flange and the cut - off wheel .