Abstract: This invention relates to a cutting mechanism and its method of operation in "cutting side-lock" portions from "green state" roofing tiles. The tiles are manufactured in a conventional concrete roofing tile making plant in which mortar fed to a hopper extruder (18) of conventional design is formed as a continuous ribbon (26) on a series of pallets (P) conveyed beneath the hopper extruder (18). The ribbon (26) is thereafter cut by a knife (3) into discrete tiles (T) on said pallets (P) with a "side-lock" portion of each tile being blanked out by extension portions (32) (34) of the knife (30). The blanked out portions are thereafter removed from the remainder of the tiles by a blade 90 of removal means 14 such that no damage is caused to the tiles (T) and little or not detritus remains on the tile or the conveyors of the tile making plant.