Abstract: A side trimmer knife having a cylindrical body with a pair of exposed faces and a cutting edge at the periphery of at least one face, with the body being defined by a pair of juxtaposed cylindrical disks of hardened steel. The disks are held in rigidly aligned relation by a plurality of cap screws extended through aligned openings in each of the disks, with the openings tapering outwardly toward an exposed face of the knife body. The head and nut for each cap screw are also tapered to fit in the tapered openings to forcibly draw the disks toward each other and maintain their lock with the disks after repeated grinding of the faces of the body for the purpose of renewing the peripheral cutting edge.