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

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The Stroton cobalt drill bits featured a round shank with a low-profile stepped split point. They performed smoothly with or without center-punch starter guides. Unlike the more exaggerated pilot-style stepped points found on the DeWalt and Milwaukee bits that we tested, this design only stepped up a total of about 0.5 millimeters above the shoulders of the bit point, despite having more steps. Only use cobalt bits for drilling holes in metal, as the bits are too powerful for wood and other materials. 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. 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? Step drill bits offer the advantage of fast, clean precision drilling into thin metals without changing bits. Each of this set of three cobalt step drill bits is designed and engineered to drill up to 1,000 holes into 14-gauge steel. They feature a rapid strike tip for faster starting, elongated dual flutes to reduce heat buildup, and smaller step gradients for smoother drilling.

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. 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. Counterbore. Counterbore drill bits create holes that allow the head of a fastener to sit below the material’s surface. Unlike countersink bits, which create an angled hole for fasteners with angled heads, counterbore drill bits create a larger hole at a shallower depth. A counterbored hole creates a flat ridge on which the head of the fastener can rest. Tool Steel with Tungsten Carbide Tips– TCT provides a longer working life for the bit while allowing for a more stable and solid tip and enabling it to withstand more rigorous drilling applications. Cobalt drill bits consist of steel with a small percentage of cobalt—the higher the percentage of cobalt, the more heat-resistant and durable the drill bits will be. The amount of cobalt in a drill bit varies. An M35-grade cobalt bit contains 5 percent cobalt, while an M42-grade cobalt bit contains 8 percent. The higher the grade, the more expensive the bit. Tip PointDon’t throw away dull drill bits. Instead, sharpen them with a grinder to restore their sharp edges. 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. 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.

Carbon Steel– This material provides a drill bit with better durability and hardness, therefore increasing the life of the bit. Carbon steel can withstand higher temperatures and is more suitable for harder materials. M42 cobalt drill bits, which have 8 percent cobalt, are the hardest drill bits available. Why Trust Bob Vila 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. Drill bits are cutting tools that are used to remove material in a piece to create a circular hole. Having the right size and the right type of bit is key in ensuring the highest standard of work and ensuring that you can drill with confidence and accuracy. Learn more in our drill bit sets guide. 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.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.

There aren’t many materials strong enough to put holes in hardened steel. For that kind of strength, the only answer is cobalt alloy drill bits. 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.

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Titanium drill bits are durable and will hold up much longer than standard high-speed steel drill bits, but they are not as strong as cobalt alloy, which will drill through hard metals, including titanium. Q. What are the hardest drill bits? 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.) 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.