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

Product Information

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.

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. 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. 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.Only use cobalt bits for drilling holes in metal, as the bits are too powerful for wood and other materials. 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.

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 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 Point Since the manufacturer recommends these bits for cordless drilling, we tested the Milwaukee step bits twice, first in the drill press and then in a handheld cordless drill. They drilled fast and clean as billed. Then we tested the step bit’s unique ability to enlarge existing holes—a task that is nearly impossible to do cleanly with conventional twist bits. We clamped an old steel electrical junction box to the workbench and used the #9 step bit in a cordless drill to widen the punch-out holes from ½ inch to ⅞ inch. The resulting hole was perfectly shaped, clean, and smooth, with no burs.This 13-piece set from Amoolo comes in at a fraction of the price of other cobalt drill bit sets. This set is durable, with 5 percent cobalt steel alloy, though not as strong as M42 bits, which contain 8 percent alloy. Using a lubricant or cooling water can help extend the life of these bits. Their split-point tips prevent walking and make starting holes easier. Ranging in size from 1/16 inch to ¼ inch, these bits come in a plastic carrying case with labeled sizes. 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? Countersink. Countersink drill bits create shallow holes that allow the head of a fastener to sit flush with the material and are angled to match the tapered head of the fastener. Cobalt countersink bits will create countersink holes in hard metals. Unlike twist drill bits, which include self-piloting tips, countersink bits require an existing hole to drill into a material. To drill countersink holes, twist bits are needed to drill the initial hole, then countersink drill bits are used to create the countersink holes. 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. Don’t throw away dull drill bits. Instead, sharpen them with a grinder to restore their sharp edges.

Because the step bit’s cutting edges run from top to bottom along the edges of the flutes, instead of at the tip only like twist bits, we approached resharpening differently. We clamped the bit in a vice and used an angle grinder to touch up the cutting edges. It worked fine, but we had to be extra cautious not to damage the size markings. 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. 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? When attempting to drill through a hard, smooth surface, having the right tip is crucial. Most cobalt drill bits have tips with stepped and split points that bite into the metal, which prevent the bit from sliding along the smooth surface. Shank 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.

What materials are used for drill bits?

The Bosch cobalt drill bits offer a unique combination of structural features and extra-hard M42 alloy that make them a pleasure to work with. To test this product, we used a cordless drill and a drill press to highlight the difference between precision drill press work and handheld drilling. The cordless drill mostly worked well, but its variable-speed trigger made it more difficult to maintain a slow, precise speed for drilling steel. 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. 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. 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. 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.