An adjustable stroke mechanism has a housing with a central axis and a wall enclosing a cavity. At least one counterweight is movably disposed within the cavity. A mounting assembly is disposed within the cavity. The mounting assembly has a workpiece attachment mechanism. A stroke adjustor couples the at least one counterweight with the mounting assembly. The stroke adjustor enables the counterweight and mounting assembly to move with respect to one another such that a distance between the counterweight and the mounting assembly is variably adjusted which, in turn, variably adjusts a stroke radius of the workpiece attachment mechanism with respect to the central axis of the housing.