Abstract: A slotter head having slotter knives which are carried by the slotter head and are adjusted circumferentially with respect to one another simply by manually operating a handle which functions to release a locking mechanism. With the locking mechanism released, one of the slotter knives can be adjusted circumferentially with respect to the other knife simply by manually rotating an annular plate to which it is removably affixed. Thereafter, the handle is again manipulated to cause the locking mechanism to lock the rotatably adjustable annular plate carrying the slotter knife to position the slotter knife in a fixed position with respect to the other slotter knife.