10 Best Bits To Drill Through Steel in 2026

The M35 cobalt composition and TiAlN coating are what make this set stand out for drilling hardened steel. That coating handles temperatures up to 1472°F, which directly translates to less friction and a longer-lasting edge when you’re pushing through stainless or alloy. The innovative triple-flute geometry on most bits isn’t just for show, it clears chips about 40% faster to keep everything cooler and gives you a cleaner, more accurate hole. For a pro or serious DIYer facing a variety of tough metals, this 21-piece set hits the sweet spot of material science and practical design, justifying its position as a top contender.

Designed for standard depth-of-cut applications, this set is optimized for typical drilling tasks rather than extreme plunges. Its triple-flute geometry improves chip ejection by about 40% for cooler operation and provides superior hole roundness. The smallest bits, from 1/16″ through 7/64″, use a two-flute design for delicate work, while sizes 3/32″ and up feature the performance triple-flute design.

With 29 pieces ranging from 1/16″ to 1/2″, this set provides a comprehensive solution for anyone who regularly drills into steel and other metals. It’s the ideal core set for a workshop or service truck where you need to tackle a variety of hole sizes in steel plate, angle iron, or tubing. Our research and owner feedback confirm these are reliable, go-to bits for metal drilling with a cordless tool.

Its case measures roughly ten inches long and weighs nearly three pounds, making it a larger kit than more compact options like the 14-piece Bosch CO14B. For a technician making service calls or a DIYer with limited storage, that footprint is a real consideration. While the expert guide highlights these bits for general steel, drilling exclusively in hardened materials may require a more specialized product.

An 8% cobalt M42 alloy means these bits can take the heat when you’re pushing through stainless steel or cast iron, which is exactly what you need for tough jobs. The surface-hardened tip bites into hardened materials that would dull standard bits, making this set a solid choice for the metalworker tackling a mix of projects from fabrication to repair. It’s built for the user who needs durability without stepping into the premium price tier.

While the Bosch CO14B set handles hardened steel well, owner feedback suggests it can wear more quickly if you’re consistently drilling work-hardened material without proper lubrication. Compared to a set like the Bosch CO21 with its three-flat shank for better grip in chucks, this 14-piece kit is a more straightforward, jobber-length option. It delivers core value for general metal drilling, but for the heaviest, most abrasive applications, you might find yourself reaching for a cutting fluid bottle more often.

Impact-rated for use in 1/4-inch hex drivers, these bits are built to handle the high torque of an impact driver. Their titanium nitride coating is stated to last 2.5 times longer than non-coated bits when working through tough materials. A 135-degree split point geometry is included for faster starts and reduced walking on surfaces. This set is designed for drilling ferrous metal, wood, plastic, non-ferrous metal, cast iron, and stainless steel.

The trade-off for that impact-ready design is a more focused selection. With 14 pieces, you have a solid range for common tasks, but you won’t have the extensive sizing options of a 29-piece set like the Milwaukee Red Helix Cobalt. It’s a compact, purpose-built kit. For drilling exclusively with a drill press or corded drill, a dedicated cobalt set like the Bosch CO21 might offer more metal-specific geometry. For blending power tool versatility with metal penetration, this Makita set fills a specific niche.

Irwin’s 29-piece set covers a wide range from 1/16-inch to 1/2-inch in small increments, which means you’re likely to have the exact size needed for most common tasks. A 135-degree split-point tip is designed to start drilling immediately with less force and to eliminate walking across the work surface. Premium high-speed steel is specified to withstand extended drilling in tough materials, and a black and gold oxide finish provides corrosion resistance.

The trade-off is material. High-speed steel is less heat-resistant than the cobalt alloy in sets like the Bosch CO21, so it will dull quicker under sustained, heavy use in tough metals. For drilling a few holes in angle iron or sheet metal, however, this Irwin set gets the job done without fuss. The organized metal case is a nice touch that keeps your shop bench tidy, even if it adds a bit of heft to your toolbox.

Designed for very high drilling temperatures, this Bosch set tackles stainless steel and other hard materials effectively. Its cobalt construction resists softening under heat, a key advantage for fabricators or serious DIYers working with tough alloys. The no-skate split-point tip provides accurate starts without walking, which is crucial on curved or hard surfaces. You get a practical range of 21 sizes in a case, covering tasks from pilot holes to half-inch clearance.

Research mentions these bits can wear out more quickly when used on work-hardened steel without cutting fluid. Compared to standard high-speed drill bits, Bosch states these cobalt bits provide four times longer life and are built for higher temperatures. The set includes more bits and a wider size range than some competing cobalt sets like the Spyder Mach Blue, offering value for the money.

The 5% cobalt alloy composition is the headline here, giving these bits the extra heat and abrasion resistance needed for repeated drilling in tough steels without losing their edge. This makes the set a reliable, long-lasting choice for a shop that regularly tackles fabrication, metalworking, or automotive projects. The full run of 1/64-inch increments from 1/16 to 1/2 inch means you’ll almost always have the exact size bit for a tap drill or clearance hole, eliminating compromises.

The trade-off is in the footprint. The case is over a foot long and wide, which demands a dedicated drawer or shelf space in your toolbox. For a more compact, job-site-friendly cobalt set that still handles steel, the Bosch CO21 with its three-flat shank is worth a look, though it offers fewer pieces. If your work is predominantly with wood or plastic, the cobalt here is overkill, and a standard high-speed steel set would be more practical.

The 135-degree stepped point is the standout feature here. That geometry bites into steel and acrylic with less walking and pressure, so you’ll spend less time center-punching and more time making chips. Combined with the gold oxide cobalt construction, these bits start easier and reduce heat compared to standard drill bits. This set is for the fabricator or serious DIYer who needs a reliable, comprehensive range of sizes. It handles creating new holes or cleaning up existing ones in tough materials, with the convenience of a dedicated storage case.

You trade some versatility for that specialized performance. The jobber length is fine for most tasks, but it won’t handle deep structural steel like an aircraft-length bit would. And while the three-flat shank is excellent for grip on the larger sizes, you’re back to a standard round shank on bits 11/64″ and smaller. If your work is exclusively in stainless or hardened steel, these are a mainstay. For a more durable but brittle option at a higher price per bit, the research mentions Drill America Carbide bits.

Titanium nitride coating extends the life of the drill bits, offering a step up from basic coatings. The pilot point geometry starts on contact for cleaner holes, which helps keep the bit from skidding when you begin a drill. With a 29-piece range up to 1/2 inch in a tough case, this set organizes a wide spread of sizes for varied tasks.

The coating is a surface treatment, so the underlying high-speed steel is exposed once it wears. Other products like the Crosstar M35 Cobalt set use solid cobalt alloy, which is a different material construction. For general drilling where clean hole starts and organized storage are priorities, the DEWALT set’s design focuses on those features.

The black oxide coating provides a good layer of rust protection for a workshop environment, and the 3-flats shank gives you a solid mechanical grip in the chuck. For the DIYer or generalist who needs to drill through steel occasionally but also works with wood and plastic, this 29-piece HSS set covers a lot of ground with a sensible, durable design. It’s a reliable workhorse for mixed-material tasks.

This 29-piece set uses high-speed steel, a material also found in the similarly-sized Irwin set. For applications involving frequent drilling in harder metals, other listed products like the Bosch CO21 set specify cobalt construction for stainless steel and cast iron. The DEWALT set’s tapered web design aims for durability and resisting breakage under typical use conditions.