10 Best Cobalt Drill Bits in 2026

Research indicates M35 cobalt offers an attractive balance of price and performance for general steel drilling with a cordless tool. The Milwaukee Red Helix Cobalt Drill Bits are noted for excellent success in that role, becoming a go-to choice for metal drilling. For a professional or serious DIYer needing reliable performance on steel and hard metals, this comprehensive 29-piece set delivers right from its case. Owner feedback consistently ranks these bits above other major brands for this specific task.

You do trade some compactness for that comprehensive 29-piece range; the case is substantial, measuring 9.9 inches long and weighing 2.9 pounds. For most workshop metalwork, however, this set has everything you need for standard hole sizes in steel and hard metals.

The Bosch CO14B set’s 8% cobalt M42 alloy and surface-hardened tip are engineered for the high heat and abrasion of drilling hardened steel. That’s the core reason it’s a standout for pros and serious DIYers who regularly tackle stainless steel, cast iron, or titanium. The thick web-helix design adds rigidity, so the bit is less likely to wander or snap under pressure. This set is built for durability in the toughest materials, not for light-duty shop work.

The trade-off is in the bit count and, according to research, ultimate longevity against the very best. You get a solid 14-piece range from 1/16″ to 1/2″, which covers most common metalworking tasks. However, if you need a more extensive size selection, the 29-piece Milwaukee Red Helix set offers more than double the pieces. For the money, Bosch delivers excellent value with its premium M42 material in a practical, durable package for hardened steel.

The standout feature is the 135-degree stepped split point, which bites into material instantly to prevent walking, especially on curved surfaces like pipe. It is designed for enlarging existing holes or drilling tough alloys like stainless steel. Research mentions highlight Drill America’s cobalt bits as a top choice for hardened metal. The gold oxide finish adds a layer of lubricity, and the sizes from 1/16-inch to 1/2-inch in 64th increments mean you’ll almost always have the exact bit.

A trade-off exists in the shank design. Bits 11/64-inch and smaller have a round shank, while larger sizes feature a 3-flat shank to prevent spinning in the chuck. You lose that anti-spin security for the smallest, most fragile bits. For general heavy metal drilling and hole enlarging, however, Drill America’s stepped point remains an advantage.

This 29-piece set includes every size from 1/16″ to 1/2″ in precise 1/64″ increments. That completeness means you’ll almost never be stuck using a bit that’s slightly too large or small for a precise tap or clearance hole. Combined with the M35 cobalt construction and a wear-resistant gold oxide finish, it creates a foundational set for a workshop that regularly tackles stainless steel or hardened metals. It suits the mechanic or fabricator who needs the right bit on hand for any fastener or project detail.

Weighing 2.2 pounds, the complete set is better suited for a stationary shop than for carrying to every job site. For a lighter cobalt option, the 14-piece DEWALT kit weighs 0.8 pounds. The Drill America set provides a full sequence of sizes intended for shop use where portability is less critical.

Covering a full range from the smallest 1/16″ size up to 1/2″ in 1/64-inch increments, this 29-piece set gives you a tool for just about any metal drilling job in the shop. The 5% cobalt alloy and heavy-duty web construction mean these bits can handle the heat and abuse of drilling into hardened steel without immediately dulling. For a hobbyist or a pro looking for a quality index set to use with a handheld drill, this is a solid, affordable foundation that won’t leave you searching for the right size.

The bits use an M35 cobalt alloy, which research mentions as notably less expensive than the M42 grade used in some premium sets. This makes the set a solid choice if you’re looking to save money or need a quality index set for use with handheld drills. The trade-off is that M35 alloy does not have the same level of heat resistance as M42.

The triple-flute geometry is the standout feature here. It is designed to eject chips about 40% more effectively than a standard two-flute bit, which means less heat buildup and a cleaner, rounder hole when working through stainless steel or hardened alloys up to 60 HRC. Combined with the heat-defying TiAlN coating and a non-slip three-flat shank, the design caters to the metalworker who values a precise finish. It also handles the torque of an impact driver without slipping.

One limitation is that the very smallest bits in the set revert to a two-flute design, so you don’t get the triple-flute benefits on your finest work. For a shop that constantly drills deep holes or needs maximum bit count, the 21-piece set might feel lean compared to something like the 29-piece Drill America M35 Cobalt set. However, if your priority is cleaner, faster, and more accurate drilling in tough materials at common depths, this set’s engineered geometry delivers a distinct advantage.

A pack of twenty identical 1/8-inch M35 cobalt bits is built for a specific, high-volume task. This is for the fabricator or metalworker who goes through a lot of the same size, whether for repeated hole patterns, production work, or simply keeping spares on hand to avoid downtime. The 5% cobalt content and 135-degree split-point tip mean these bits are formulated to tackle stainless steel and cast iron without walking. Having so many on deck means you can swap in a fresh one without stopping the job, making it a straightforward solution for a straightforward need.

Its focus is depth in one size, not breadth. You won’t be drilling a pilot hole or a clearance hole with this pack alone. For a comprehensive workshop kit, you’d need to pair this with other sizes or look to a full set like the Drill America M35 Cobalt Drill Bit Set. That set offers a complete range from 1/16-inch to 1/2-inch. The RCINDUS pack excels not as a general-purpose set, but as a specialized, bulk refill for the most commonly used bit in your arsenal.

This set’s standout feature is its connectable, bit-bar storage system, which lets you organize and access bits exactly how you want. For a tradesperson or serious DIYer whose drill index lives in a packed toolbox or job-site cart, that intelligent, compact design is a serious space-saver. The clear lid and secure clip mean you can find what you need instantly without bits spilling out. It’s a smart pick for anyone who values a tidy, modular kit that fits inside a larger system.

Research comparing various cobalt bits notes one brand’s model drilled over three times more holes than the best cobalt bit from DeWalt, though the tested DeWalt bit was not this specific set. With 14 pieces, this collection offers fewer sizes than larger 29-piece kits, such as the Milwaukee Red Helix. This means you’re choosing a compact, organized storage system rather than maximum bit life or the widest range of diameters.

A 15-piece set covering 1/16″ to 3/8″ hits the sweet spot for the occasional metalworker or dedicated DIYer. The M35 cobalt construction and 135-degree split point deliver the precise, walk-free drilling needed for stainless steel or hardened metal, but the limited count and size range keep the focus on common tasks. This is the kit you pull out for assembling a bracket, modifying a tool, or tackling a short list of holes, not for a full-day fabrication job.

The GMTOOLS set offers a focused selection of fifteen bits, prioritizing the most frequently used sizes over a comprehensive range. This makes for a compact and typically more affordable kit compared to larger sets like the 29-piece IRWIN M35. For drilling tasks in hardened metal or cast iron around a home workshop, this concentrated set keeps the most useful sizes within easy reach.

A 19-piece metric set spanning 1mm to 10mm means you have the right size for everything from fine metalwork to general fabrication without skipping half-millimeter increments. This makes it a natural fit for anyone working with metric fasteners or machinery, where that precise sizing eliminates guesswork and sloppy fits. The M35 steel with 5% cobalt is formulated to bite into hardened materials like stainless steel, so you can push it harder without immediately blunting the tip.

One consideration is the range; if your projects routinely call for holes larger than 10mm, you’ll need a supplemental set. For those focused solely on imperial measurements, a set like the Drill America M35 Cobalt would be a more direct match. Yet for the metric workshop, this NewShark collection delivers a logically organized foundation of durable bits that cover the vast majority of common drilling tasks in tough materials.