10 Best Drill Bits For Drilling Hardened Steel in 2026

The 5% cobalt alloy in these bits is the key feature for tackling hardened steel. It withstands the extreme heat generated when drilling tough materials, preventing the premature softening that ruins lesser bits. This makes the IRWIN set a reliable, durable choice for a workshop that regularly encounters stainless steel, alloy steel, or other hardened metals. The comprehensive size range in 1/64-inch increments means you’ll likely have the exact bit you need without compromise.

Its case is over a foot long, so it takes up more bench or drawer space than many other kits. For comparison, the Drill America M42 Cobalt set comes in a case that is significantly smaller in every dimension. The IRWIN set’s heavy-duty web construction is noted for added strength, which contributes to durability during use.

A set manufactured to Aerospace Standard 907 is built for serious, repeated use in demanding materials. The M42 cobalt composition delivers high red hardness, which means you can push these bits about 30% faster than standard M2 steel without losing their edge. That’s a tangible time-saver when you’re facing a stack of stainless steel or titanium plates. This set is for the metalworker or fabricator who needs predictable, high-performance drilling and can’t afford bit failure mid-job.

Gold oxide acts as a lubricant and resists wear, so the bits can handle tougher materials without degrading quickly. M42 cobalt alloy is effective for drilling tough, high tensile strength materials like stainless steel, Inconel, and titanium. Manufactured to Aerospace Standard 907, this set displays high red hardness, permitting speeds up to 30% greater than conventional M2 high speed steel for demanding metalwork.

An 8% cobalt M42 alloy gives these bits their high-performance edge. This lets you push into tough materials like stainless steel and titanium without the tip immediately failing from heat. The thick web-helix design adds the stability needed for those demanding applications. This Bosch set is a solid choice for the metalworker who needs durability and heat resistance from a trusted brand without a premium investment.

Owner feedback confirms these bits deliver solid performance, but notes they can wear out more quickly if you’re drilling into work-hardened steel or skipping the cutting fluid. For the user tackling a steady diet of the hardest alloys, they’re a reliable workhorse. If your primary need is drilling hardened steel in bulk, the larger Drill America M42 Cobalt set offers a greater number of bits in a similar material.

A hex-shank design rated for impact drivers means these bits are built to handle the high torque and jarring action of modern cordless tools without slipping or breaking. The titanium nitride coating isn’t just for show; it significantly reduces friction, which keeps heat down and extends bit life when you’re pushing through heavy-gauge or high-carbon steel. This set is a natural fit for anyone who primarily uses an impact driver or high-torque drill for metal fabrication, automotive work, or heavy-duty fastening where precise starting is critical.

This nine-piece Bosch set is designed for heavy-gauge and high-carbon steel, so it targets a specific range of tough materials rather than every possible metal. Its titanium nitride coating reduces friction, which helps when using higher-torque impact drivers. The bits are impact-rated for that extra torque, making them a focused choice for common steel tasks rather than a comprehensive workshop collection.

The bullet point tip design enhances centering performance and reduces deviation during drilling, making it easier to start holes accurately. These bits are built with M35 cobalt material and a TiAlN coating, which provide a hardness of up to 70HRC to minimize wear. This combination can handle a variety of materials like copper, aluminum, iron, common alloys, wood, and plastic. This set is a solid choice for a mechanic or fabricator who values precision and needs a reliable set for mixed-metal tasks.

With 20 pieces covering 14 specifications, including duplicates for commonly used sizes, this set covers most usage needs. It is a more compact offering than the 29-piece Drill America M42 set, making it better suited for a focused toolbox than a comprehensive shop inventory. The materials and tip are right for the listed materials, but if your projects demand a complete size progression, you’ll find the selection here more limited.

A stepped tip that doesn’t require a pilot hole makes starting a hole in hardened steel quicker and more direct, saving setup time. The stubby mechanics length is the key feature here. Its reduced flex makes it far less prone to snapping when you’re applying the high side pressure needed in a confined corner or against an obstruction. This set is built for the mechanic or fabricator who needs to drill out a broken bolt in a recessed flange or add a hole in a tight engine bay. In such spaces, a standard-length bit would chatter and break.

The trade-off for that compact, break-resistant design is reach. You won’t be drilling through a deep block or a thick sandwich of materials with these. Compared to a full-length 29-piece set, you’re exchanging versatility in depth for supreme durability and control in cramped quarters. Just remember the manufacturer’s clear directive: you must use oil lubrication when drilling metal with these bits to manage heat and protect that premium M35 cobalt edge.

With 115 pieces covering fractional, letter, and number sizes, this set provides the specific bit needed for precise holes in metalworking tasks. The M35 cobalt alloy is specified for drilling hardened metals like stainless steel, and its 135° split point is designed to prevent walking on curved surfaces. An indexed metal case organizes all the included sizes.

The complete set weighs 7.5 pounds, which some users may find substantial for transport. A 29-piece set in a round case, listed at 2.2 pounds, offers a lighter alternative for the same fractional size range. The HIDOTOL case measures 13.5 inches long, requiring more storage space than some other kits.

The RCINDUS M35 Cobalt Drill Bit Pack contains twenty identical 1/8-inch bits, which allows for continuous work on projects requiring many holes of the same size without stopping to sharpen a single bit. Its M35 alloy includes five percent cobalt for hardness that can drill materials like stainless steel and cast iron. A 135-degree split point on each bit is designed to prevent walking on hard surfaces, so it starts drilling exactly where you place it.

The limitation is clear: you only get one size. For a comprehensive set covering a range of diameters, you’d need to look at a larger 29-piece set. But if your work consistently calls for a 1/8-inch hole in stainless or cast iron, this pack delivers a lot of capable drill bits for the money. They are all held in a convenient case to keep them from rolling away.

The five multi-range step bits are the core advantage here, letting you drill a wide variety of hole sizes from 1/8 inch up to 1-3/8 inches without swapping tools. That makes this COMOWARE set a serious time-saver for anyone working with sheet metal, ductwork, or electrical panels where you need stepped or clean holes in thin stock. The M35 cobalt construction provides the necessary heat resistance for pushing through hardened steel, and the self-starting split point helps keep the bit from skating off a curved surface. This is a pragmatic choice for a fabricator or mechanic who values a streamlined kit over a comprehensive array of individual bits.

This is a set of step drill bits, so it’s designed for versatility across diameters rather than for deep, single-diameter holes. The bits excel at thin materials like sheet metal, and the included ranges are generous, but the set doesn’t include any standard fractional bits below 1/8 inch. It’s a focused solution. If your work involves a lot of pilot holes or tapping holes in thick steel, you’ll likely need to supplement this kit with a separate set of small-diameter cobalt bits.

The inclusion of three M35 cobalt step bits, five countersink bits, a hex adapter, and an automatic center punch makes this a uniquely comprehensive kit for specific metalworking tasks. It’s built for the fabricator or electrician who frequently needs to create clean, burr-free holes in sheet metal and then immediately finish them with a countersink. The M35 cobalt construction and titanium coating are the right materials for pushing through hardened steel without rapid dulling, while the anti-slip hex shank and clear markings provide the control needed for precise work.

The trade-off is scope. This is a specialized hole-enlargement and finishing kit, not a foundational drill bit set. You’ll still need a separate set of standard twist bits, like the IRWIN M35 Cobalt Drill Bit Set, to establish your initial pilot holes in tough materials. For a user whose projects consistently involve installing conduit, creating wiring pass-throughs, or working with electrical boxes, however, having every tool for that workflow in one organized case is a significant efficiency gain.