A rotary drum filter apparatus comprising a rotary drum, a plurality of axial, parallel slots spaced circumferentially around the drum, a filter cloth positioned peripherally around the drum and portions thereof extending into each of the axial slots, flexible metal means inserted into each of the slots over the portion of the filter cloth extending into the slots and caulking means for holding each of the metal means and each of said portions of said filter cloth in a locked position in their respective axial slots. The metal means may comprise a stranded metal cable wherein caulking means are unnecessary.