A means and method of installing emitters in irrigation tubing, wherein a core assembly dimensioned for ready insertion in a thinwall irrigation tube is provided with internal rollers which are confronted by fixed external rollers positioned to function through the walls of the irrigation tube so as to retain the core assembly in a fixed position as the tubing is moved between the internal and external rollers; the core assembly including an anvil periodically engaged by an external radially movable cutting tool to form in the irrigation tube a series of emitter receiving perforations; the core assembly also including a fork member for spacing the perforated wall of the irrigation tube from the opposite wall thereof to facilitate reception of emitters forced therein by an external mandrel; the anvil and fork and their respective cutting tool and mandrel adapted to be spaced at preselected distances depending on the required emitter spacing.