cobalt drill bits are the only answer. These powerful drill bits for cast iron, aluminum, and even stainless steel are made ...

We learned a lot by sharpening 100 dull drill bits, including carbon steel, high-speed steel, titanium-coated, and cobalt options. Some of the sharpeners were less expensive and others were easier ...

"I have been using Dewalt bits for a few years now and ... The 14-piece DeWalt Assorted Cobalt alloy steel Jobber length Twist Drill Bit Set received similar negative reviews, with one user ...