This invention provides a slitter assembly with automated adjustment of slitter elements that allows for driven rotation of elements on the associated drive shaft during operation while enabling the elements to be moved freely along the drive shaft during setup and subsequently secured to the shaft free of lateral movement. This ensures that adjustment of the slitter elements is accurate, repeatable and reliable. In an illustrative embodiment, the slitter elements each comprise a pair of coaxial members including a blade member and a locking member. The blade member contains a slitter blade and overlies the locking member which is nested therewith. The locking member directly engages the drive shaft surface with a wedge assembly structure. The members are spring-loaded with respect to each other so that the two surfaces are normally biased to cam together and exert a hoop stress on the drive shaft.