Apexx Core Bits Apexx 5/8″-11 thread Long-lasting vacuum brazed core bits for marble and porcelain tile. They offer clean and chip-free holes and can be used wet or dry. Available in the following sizes: 1/2″, 3/4″, 1″, 1-1/4″, 1-3/8″, 1-1/2″, 1-3/4″, 2″, and 3″