DEWALT Cobalt Alloy Steel Drill Bit Set with Pilot Point, 14-Piece (DWA1240)

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Bob Vila has been America’s Handyman since 1979. As the host of beloved and groundbreaking TV series including “This Old House” and “Bob Vila’s Home Again,” he popularized and became synonymous with “do-it-yourself” home improvement. HSS (High-Speed Steel)– HSS can withstand higher temperatures without compromising the hardness of the bit and is able to cut faster with more accuracy and efficiency. The Irwin M35 drill bits performed well before and after sharpening—in fact, the bit had barely dulled after the first three holes. With or without a center punch to premark the hole locations, these bits drilled smooth, clean holes. Also, the split point was easy to line up at the proper angle to sharpen on the grinder. Twist– The most common type of drill bit and ideal for drilling wood, plastic, and metals. They are generally made from HSS and are suited to general household DIY tasks, as well as professional applications like maintenance and engineering.

The raised center point didn’t get in the way when we sharpened the edges of the bit point, but sharpening the center of the point was more challenging. However, we found that these durable bits, housed within their well-built hard plastic case, would make a great addition to a workshop.Machinists, mechanics, DIYers, and crafters value cobalt bits for their ability to drill hard materials and because they can be resharpened. We spent 12 hours testing these drill bit sets. First, we used a drill press to evaluate them for drilling ability in aluminum, cast iron, and stainless steel. Then we resharpened them before performing a second round of drilling tests. (For most products, we used a drill press for each set of holes; however, for two products, we used a drill press and a cordless drill, as noted above.) Cobalt Steel– The cobalt content increases the strength of the bit and aids in the resistance to heat and friction, so it can be used for more stubborn materials.

Read on to find out more about our shopping considerations and testing process. This guide will help you find the best cobalt drill bits for turning metal into Swiss cheese. The Milwaukee cobalt drill bit set exceeded our expectations in the stainless steel drilling test. While most of the other bits did a pretty good job, the Milwaukee bits bit into the stainless steel noticeably faster. The slightly elevated point, which is shorter and narrower than DeWalt’s, seemed to find a sweet spot that then allowed the rest of the cutting edge to follow. The kit includes #1, #4, and #9 step bits. The #1 bit drills from ⅛-inch to ½-inch holes, with step increments of 1/32 inch. The #4 bit makes holes 3/16 inch to ⅞ inch, in 1/16-inch increments. The #9 bit drills ⅞- to 1⅛-inch holes in 1/16-inch increments.M42 cobalt drill bits, which have 8 percent cobalt, are the hardest drill bits available. Why Trust Bob Vila Working with the Drill America M42 drill bit was almost an identical experience to working with the Irwin drill bit set, but this set is made of tougher metal and provides easier access to all of the bits at once. Both sets offer the same size assortment, the same round shank, and 135-degree split-point construction. Drill America’s bits remained noticeably sharper after the first three test holes, so we drilled a second set of three holes before sharpening. Sharpening took slightly longer, but the split point made it easy to align them with the grinder. Don’t throw away dull drill bits. Instead, sharpen them with a grinder to restore their sharp edges.

There are four types of cobalt drill bits, with each type serving a specific purpose. Understanding the right application for each bit type is essential. After drilling the first round of test holes (or after the second round for some harder drill bits), we sharpened the ⅜-inch bits with a bench grinder. We held the cutting edge to the wheel for 5 seconds on each cutting edge, once on the coarse grinding wheel and once on the fine wheel, making sure to maintain the 135-degree original tip angle. To evaluate how well the bits responded to resharpening, we drilled another round of three test holes for each bit in the scrap steel.Still wondering if cobalt bits are the best tool for the job? Read on for answers to the most common questions about cobalt drill bits. Q. Can cobalt drill bits be sharpened? It takes a tough bit to drill through hard metals like steel and bronze, but drill bits like these from Stroton are up to the task. Stroton uses what it calls a three-step design with this drill bit. Borrowing from step-bit technology, the tip of the bit is composed of three separate steps that help drive the bit through hard metals. This 19-piece metric set features sizes ranging from 1 millimeter to 10 millimeters. Drilling through steel, cast iron, and other metals produces tiny shards that can end up in skin or eyes, so make sure to wear protective gloves and safety glasses when working with cobalt drill bits.