A mounting arbor is used for inserting in openings (12) of workpieces (13) and for frictionally holding the workpieces (13) by means of radial expansion. In order to provide mounting arbors which are not subjected to any wear or malfunctions caused by particles which collect in gaps and openings of the mounting arbor (10), a resilient sleeve (20) forms an outer surface (11) of the mounting arbor (10). The resilient sleeve (20) can be elastically expanded by means of radially acting forces (Fig. 1). <IMAGE>
