Abstract: Apparatus for mounting a rotatable component on a rotating shaft using a non-machined torque transmitting intermediate hub member is disclosed. The hub member makes torque transmitting contact with the drive shaft and transmits that torque to the rotatable component through frictional contact at a taper on the drive shaft and at a recessed shoulder of the hub as well as by an external key on the hub periphery and a matching cut-out formed in the rotatable member. There is also a keyway and key between the drive shaft and hub for accurate alignment in assembly and disassembly. A plurality of narrow longitudinally extending rib members are integral with and are supported on the other peripheral surface of the hub member whereby the rotatable member when it is seated against the shoulder on the hub member for the first time mechanically distorts the rib members from their original shape to provide a secure but releasable fit between the hub member and the rotatable component.