An adaptor for a powered surgical instrument includes a casing, a cam drum, a first linear driver, and a second linear driver. The cam drum defines and is translatable along a longitudinal axis of the adaptor between a retracted position and an advanced position. The cam drum is being supported for rotation about the longitudinal axis. The cam drum defines first and second radial cam grooves about an outer surface thereof. The first cam groove defines a first profile and the second cam groove defines a second profile. The first linear driver includes a first cam follower disposed in the first cam groove and the second linear driver includes a second cam follower disposed in the second cam groove. The first and second linear drivers are supported for movement between advanced and retracted positions in response to rotation of the cam drum.