covington bead mill parts Bead Mill Covington Bead Mill Lapidary Mart Covington Bead Mill The Bead Mill makes beads from 5/16 to 3/4 in diameter The 4 1/2 x 1/2 aluminum head has a 3/8 recessed ring in the ceiling which provides a trough for the beads to follow Milling action is achieved by rotating the chamber while the head controls the beads location