Diamond Core Drill Bits Dry Slotted for effortless performance in dry coring. The steel core is built with a ribbed surface to reduce friction as it spins through all types of building materials. The diamond core drill bits high performance diamond segments are laser welded to the barrel giving outstanding safe user operation. Available in several sizes, these cores will outstrip in terms of speed and durability. A variety of adaptors and centering drills are available for a range of drilling machines. Select dropdown to view sizes.