Harlingen 7 Piece 9/16-15/16 X 1" Cutting Depth HSS Annular Cutters Harlingen annular cutters are hollow drill bits with sharp edges, designed to drill large, precise holes in various materials, including hardened steel, mild steel, and stainless steel (up to 35 HRC). High speed steel with a bright finish. Excellent wear resistance. Weldon shank - 3/4" shank diameter. Compared to standard twist drill bits, annular cutters drill larger holes more quickly and with less effort. They also deliver a smoother finish than hole saws. As the cutter rotates, it removes material in a ring shape, leaving a solid core at the center. This process results in clean holes with minimal burring. Set includes 6 annular cutters: 9/16", 5/8", 11/16", 13/16", 7/8" & 15/16"(1" cutting depth), 1 center punch & a fitted carrying case.