Soft Facing Brick, Concrete Blocks, Hard Sandstone, Coarse Sandstone, Soft Slate, Breeze Block & Lignacite Blocks. Our 172mm diamond core drills have been manufactured to a high standard to withstand the huge stresses involved when core drilling into general masonry building materials. Our diamond core drill bits offer excellent drilling speeds and lifetime when used with most core drill machines due to their high diamond concentration, high-quality barrels, back ends and 10mm segment height.