In one aspect of the present disclosure, a rotary sifter is disclosed that includes a body assembly, a drive mechanism, and a base assembly supporting the body assembly and the drive mechanism. The body assembly includes a housing, a screen frame assembly that is positioned within the housing, and a rotor assembly mounted for rotation within the screen frame assembly. The drive mechanism is in mechanical cooperation with the rotor assembly to rotate the rotor assembly, and is axially fixed in relation to the housing, the screen frame assembly, and the rotor assembly. The base assembly includes a guide rail system that is configured and dimensioned to permit longitudinal movement of the rotor assembly and the screen frame assembly in relation to the housing and the drive mechanism to allow for removal of the rotor assembly and the screen frame assembly from the housing.