Abstract: An improved cutter assembly adapted for use with a rotary edger comprising a circular spool for storing peripherally thereon a plurality of plastic filaments, such spool being receivable within a circular retainer which in turn is provided with a plurality of radially extending peripheral openings formed to direct the corresponding filaments to the exterior of the retainer. The spool and the retainer are secured for rotation on the mounting arbor of the rotary device, the retainer furthermore including an exteriorly directed peripheral groove around the circumference thereof arranged to include the filament openings. The spool itself includes a plurality of filament securing openings to facilitate assembly. In an alternative embodiment, the exterior face of the spool is cut out with a plurality of radial notches through which the filaments are passed to permit insertion of the spool into the retainer.