Abstract: Power drivers are commonly used in production to tighten fasteners such as nuts and bolts. The socket which engages the fastener is normally coupled to the drive shaft of the power driver by a square male end on the drive shaft and a complementary square female connector on the socket. These components are not produced to close tolerances and as a result there is substantial play permitting misalignment of the rotational axes of the drive shaft and the socket and some rotational freedom between the drive shaft and the socket. In accordance with the invention an anti-vibration adaptor is provided comprising a sleeve containing a cylinder of resilient material which surrounds a portion of the drive shaft and a portion of the socket, including the point of coupling, sufficiently closely to minimize misalignment of the rotational axes of the drive shaft and the socket and reduce rotational freedom.