Two Bits for the Price of One! Aanraku brings you Twofers - superior quality, low-cost grinding bits. Bead Stacker bits are used to shape the ends of your beads so they fit close together when strung. Use the Flat Topped bit to remove flanges and even out glass bead ends, allowing for more uniform stacking and aligning of beads. The Cone Topped bit slightly indents the bead hole ends to provide a better fit with jewelry spacers. No more wire or string showing on your finished projects!