Our readers keep the lights on and the weekend projects moving. As an Amazon Associate, I earn from qualifying purchases.
Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
Standard HSS bits dull quickly on metal, but cobalt’s heat resistance keeps the edge cutting. A 135° split point prevents walking, so you get clean starts without pilot holes. M35 cobalt steel retains hardness at high temperatures, making it ideal for stainless and hardened fasteners. We compare top sets by real-world performance to help you choose the right one.
I’m Rikta — the founder and writer behind FitlyFast. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
Whether you’re a pro fabricator or a weekend DIYer, the cobalt drill bits for metal here are chosen for their ability to chew through tough steel without constant resharpening.
Our Picks at a Glance
How To Choose The Best Cobalt Drill Bits For Metal
Choose a set that matches the hole sizes and metal hardness you work with. A 1/4-inch-only set won’t handle 1/2-inch holes, and cheap steel fails on hardened metal.
Understand the Cobalt Difference
Cobalt is alloyed into the steel, not coated on the surface. True M35 (5% cobalt) bits maintain their edge even under high friction heat. This matters most on stainless steel and hardened fasteners, where ordinary HSS bits lose their edge in seconds.
Check the Point Geometry
A 135° split point is the industry standard for metal. The split creates a self-centering action that stops the bit from wandering across the surface — no pilot hole needed, and no angry scratches on your workpiece. This is the feature that separates a precision tool from a frustration generator.
Sizing Up the Set
Think about the range of holes you’ll drill. Fractional sets from 1/16 inch up to 1/4 inch handle most shop jobs, but if you’re working on thick plate or engine blocks, you’ll want to step up to larger diameters like 1/2 inch. Count the pieces and check for duplicates in the sizes you use most.
Quick Comparison
| Model | Best For | Material | Point Angle | Pieces | Amazon |
|---|---|---|---|---|---|
| RCINDUS 15PCS★ Best Overall | Versatile shop sets | M35 Cobalt | 135° Split | 15 | Amazon |
| STROTON 13PCSBudget Champion | Budget-friendly daily driver | M35 Cobalt | 135° Split | 13 | Amazon |
| BAIDETS 10PcsPrecision Pick | Clean holes in soft metals | M35 Cobalt | 135° Split | 10 | Amazon |
| DelitonGude 13PCS | Hardened stainless work | M35 Cobalt | 135° Split | 13 | Amazon |
| Narwhal 1/2″ 3 Pack | Big holes in thick plate | M35 Cobalt | 135° Split | 3 | Amazon |
| LU&MN 1/4″ 10 Pcs | Razor-sharp everyday cutting | M35 HSS | 135° Split | 10 | Amazon |
| STROTON 17PCS | Full-range pro kit | M35 Cobalt | 135° Split | 17 | Amazon |
| Drill America 12 Pack | Exacting tight-tolerance work | Cobalt | Spiral Point | 12 | Amazon |
| AIMLENTOOL Hex Set | Quick-change multi-size holes | M35 Cobalt | Center Point | 6 | Amazon |
In‑Depth Reviews
1. RCINDUS 15-Piece 1/4″ Cobalt Drill Bit Set
Our pick — over 4.5★ from 850+ verified ratings; the strongest balance of quality and price.
The 15-piece kit that covers nearly every shop need without emptying your wallet.
This set wins because it gives you the most sizes to work with — 15 pieces, all at the handy 1/4-inch diameter — in a plastic case that keeps them organized. That’s 50% more bits than a comparable 10-piece 1/4-inch set, which matters when you burn through a size on a long project. The M35 steel here is the real deal, with 5% cobalt mixed in so the edge stays hard when you push through stainless or cast iron.
The sharpness is what owners rave about most. The 135° split point starts holes cleanly without walking, which is the difference between a precise entry and a scratched surface. Buyers report the bits “cut through stainless steel sheeting like butter,” and the value-for-money praise is the loudest theme in the reviews — this is a factory-direct set that skips the middleman markup.
One thing to know: it’s strictly a 1/4-inch set, not a graduated range. If your work needs smaller pilot holes or larger 3/8-inch bores, you’ll want a separate set alongside it. The diameter accuracy is held within -0.03mm, which keeps holes true to size — a detail that matters for tight engineering fits.
What wins people over
- Value for money is the undisputed highlight — dozens of owners say it outperforms the price
- Stays sharp through repeated use on wood and soft steel
- 135° split point (a self-centering tip) stops the bit from skating
- 15-piece count in a storage case beats most entry-level kits
The honest limits
- Only a single 1/4-inch size, so no small pilot bits included
- Mixed feedback on the hardest steels — it excels on soft-to-mid metals
Best all-rounder: Perfect for the DIYer who wants one solid set for metal, plastic, and wood without buying ten boxes.
Look elsewhere if: You drill 3/8-inch or larger holes daily — you’ll need a bigger-diameter set.
2. STROTON 13-Piece Cobalt Drill Bit Set (1/16-1/4 Inch)
Thirteen sizes stepping up in 1/64-inch increments, from 1/16 up to 1/4 inch.
This is the budget pick that still acts like a premium tool when you treat it right. The 5% cobalt steel is rated at 68 HRC (Rockwell Hardness Scale) — that’s the hardness number that tells you it can take on hardened fasteners. Owners have successfully drilled hardened 10.9 steel bolts using oil, slow speed, firm pressure, straight alignment, chip clearing, and frequent cooling. All those conditions matter: cobalt is tough but brittle, so rushing it is the fastest way to snap a bit.
You get a versatile drill bit set that owners keep in their bag and say “works great on several surfaces.” But on the thickest metal plate, some owners mention it struggles. That’s the honest trade-off at this price tier: it’s a strong all-rounder, not a dedicated heavy-duty specialist.
Unlike the 15-piece RCINDUS set above, which is locked to one diameter, this one gives you a graduated range that grows in 1/64-inch steps. That makes it a better first set for a new shop, since you can pilot small and step up as needed. The included case keeps the 13 pieces from rattling around your toolbox.
Smart money play: The affordability is the headline — owners repeatedly call it “high quality” for the price.
Fair warning: Overloading or bending any cobalt bit cracks it, so match speed and pressure to the metal.
3. BAIDETS 1/4″ Cobalt Drill Bits 10Pcs
German-standard precision that leaves a clean hole with zero cracking.
What sets these apart is how cleanly they start. Built to the German DIN338 standard, the 135° quick-cut point bites the edge sharply and makes a nice reference mark for perfect alignment on a drill press. Owners drilling ABS plastic report “a clean hole with no cracking or stress” — a sign the geometry is right, not just the material. That same precision translates to metal, where it pre-drills deck screws and punches through aluminum for pop rivets without complaint.
The fully ground spiral groove design clears chips quickly, which cuts friction and heat. Less heat means the M35 edge survives longer, and the straight shank prevents walking so your hole lands exactly where you marked it. It’s also the only set here explicitly noted as not suitable for glass, stone, or ceramic — so keep it to the metals and woods it was made for.
At 10 pieces, all 1/4-inch, it’s a smaller count than the STROTON set above, but owners treat it as a direct replacement for dull bits in their cheap sets. One noted the 1/8-inch version is a bit short for some jobs, so check the length if you need deep reach.
Reach for this if: You value a sharp, precise start and mostly cut soft metals, aluminum, and wood.
Think twice if: You need deep holes in thick steel — the shorter bits limit reach.
4. DelitonGude 13-Piece M35 Cobalt Twist Drill Bits
The set that drilled bronze where a leading titanium brand failed.
Quality is the loudest theme in the reviews here — owners consistently call these well-made and effective, with standout results on stainless steel. In one direct head-to-head, these bits drilled bronze successfully where Milwaukee titanium bits failed, using slow speed and cutting oil. Another owner drilled 7 ports into 1/8-inch hardened stainless steel with a single bit and still had 9 bits left. That’s the kind of value that makes a set feel like a pro purchase.
The full-grinding nitriding finish (a surface hardening treatment) boosts wear resistance, and the spiral groove design moves chips out fast so the cut stays cool. The 135° tip twists into the work with self-centering action, which means no pilot hole and no wandering. Sizes run from 1/16 inch through 1/4 inch in 13 imperial steps, covering most drilling needs from basic to professional.
Be honest about its limits: durability gets mixed reviews, with some owners reporting bits break easily if pushed too hard on very hard T-posts. The consensus is these are excellent for normal use — the edge case of repeated abuse on high-hardness steel is where M35 shows its ceiling compared to pricier M42. Use cutting oil and a steady hand and they reward you.
Outperformer: Beats bigger-name brands on tough metal, at a fraction of the price.
Handle with care: Cobalt’s brittleness shows when you push hard without lubrication.
5. Narwhal 1/2 Inch Cobalt Drill Bits (3 Pack)
A 1/2-inch brute with a 4-inch flute that put holes in Jeep lug studs.
Sometimes you need raw diameter, and this 3-pack delivers exactly that. Each 1/2-inch bit runs 6 inches total with a 4-inch flute length (the spiral cutting section), making it the pick for thick steel plate and heavy equipment. Owners have drilled out Jeep lug nut studs after the OEM nuts failed, and punched 10 holes through 3/16-inch galvanized steel with the edge staying sharp and unchipped. The 135° split point and fully ground M35 body handle the repeated holes that kill lesser bits.
What wins people over is the quality — it’s the most-discussed trait by far, and owners say these cut metal well and hold an edge that can be resharpened multiple times. One drilled through 3/8-inch steel at a 25-degree angle, with the caveat to use lubricant. That’s the recurring wisdom across this category: cobalt does the work, but cutting oil and the right speed make it last.
Two fit notes from the owner feedback: the bits sit loose in the storage tube, and the round shank has no flats, so there’s a slight slippage risk in a chuck. Tighten it well and you get a tool that, as owners put it, is “worth every penny.”
Built for the heavy jobs
- Huge 1/2-inch diameter cuts thick plate that smaller sets can’t touch
- Survived drilling out hardened lug studs without losing the edge
- Sharpenable repeatedly — owners say it holds a true, straight cut
Worth knowing
- No flats on the shank means it can slip if not clamped firmly
- Loose fit in the included tube — consider your own organizer
6. LU&MN M35 Jobber Drill Bits, 1/4″, 10 Pcs
Razor sharpness that drilled 8 holes in a John Deere bucket and stayed just as keen.
Metal-drilling performance is the most-praised trait in the reviews. One owner drilled 8 holes into a John Deere bucket to mount hooks and D-rings, expecting to burn through two or three bits, and found the single bit was “just as sharp on the 8th as the first.” Others report it cut through metal tubing that their B&D and Milwaukee bits only dented. That’s the M35 difference: the 5% cobalt lets the edge shrug off the heat that kills ordinary steel.
The 135° split point and fully ground flute work together — the point self-centers to prevent walking, and the ground flutes clear chips efficiently so friction stays low. It’s an industrial-grade design for automotive and metalwork, with a round shank that fits any standard chuck and drill press. Stainless steel is a specialty here, with the standard reminder to avoid overheating the material itself.
The honest split: quality and durability draw mixed feedback. One owner noted the smallest bit broke after about a minute of use, which is the brittle-cobalt caution again. Drill performance, though, is overwhelmingly positive — these cut what they’re supposed to cut.
Edge keeper: The sharpness that outlasts leading brands on the same job.
Mind the small ones: The tiniest bits are fragile if you lean on them too hard.
7. STROTON 17-Piece Cobalt Drill Bit Set (1/16-1/2 Inch)
The 17-piece master set that cut stainless “like a hot knife through butter.”
This is the one that makes people switch brands. The 17-piece range spans 1/16 inch all the way up to 1/2 inch, with duplicates in the most-worn sizes (two each of 1/16, 3/32, 1/8, and 1/4). That’s a complete shop in one case — drill small pilots and step up to 1/2-inch bores in the same kit. The M35 steel at 68 HRC is the same hardness as the budget STROTON above, but here you get the full size range and the higher piece count.
Quality is the standout theme, and the cutting edge is ground three times for precision. One 76-year-old woodworker called it the best and highest-quality set he’s ever owned, praising how the bits stay sharp through steel and iron plates, leaving clean holes every time. Another owner drilled 8 half-inch holes through 1/4-inch steel and the bit “stayed sharp so far.” The performance on stainless is where these shine, drawing the butter comparison more than once.
The recurring counsel across every serious metal review applies here with force: use cutting oil, go slow, and you’ll get “nice clean ribbons” of chips instead of grinding dust. The mixed durability feedback mostly traces back to bits being pushed past their limit — treat them right and they’ll outlast the project.
Why it earns the pro label
- Full 1/16-to-1/2-inch range covers nearly every job in one case
- Triple-ground cutting edge for clean entry and true-size holes
- Duplicates in the small sizes where bits break most often
The trade-off
- Pricier upfront, though owners say cost-per-hole drops fast
- Hardened steel still demands oil and a patient hand
8. Drill America DWDCO1/4 1/4″ Cobalt Drill Bit (Pack of 12)
Twelve precision-ground 1/4-inch bits built to a National Aerospace standard.
Here’s the pick for buyers who need exacting tolerances. Each bit is manufactured to National Aerospace standard 907, which means the grind and dimensions are held to a tight spec — the kind of requirement that separates machining work from hobby drilling. Owners use these on titanium and zirconium successfully, which is about as hard as drilling gets. The gold oxide finish is a thin surface treatment that identifies cobalt steel, and performance is similar to uncoated tools.
The quality is the dominant praise, with owners calling the grind “very nice” and the bits “very sharp.” In a direct comparison, these outperformed Max Tool No. 54 bits on 3/16-inch steel — the Max Tool bits failed on the same material. That’s the aerospace-standard build showing up in real work. The spiral flute evacuates chips up and out of the cut in a right-hand (counterclockwise) rotation, reducing clogging on deep holes.
Two honest notes: the size draws mixed feedback, with some finding they run small versus the listed 1/4-inch, and in one batch two of twelve bits slipped past inspection with a wrong grind. With 10 of 12 great, the value math still works — especially since owners use them as their go-to for the hardest jobs.
Precision buy: For titanium, zirconium, and spec-critical work that cheap bits can’t handle.
Inspection note: A rare bad grind slips through — check each bit before a critical cut.
9. AIMLENTOOL Hex Shank Cobalt Step Drill Bit Set
Six step bits that climb from 1/8 inch to 1-3/8 inch without changing tools.
Step drills are the multi-tool of the drilling world, and this set is the pick if you want to deburr and drill multiple hole sizes in one pass. The six bits cover ranges from 1/8 inch up to 1-3/8 inches, with the M35 cobalt fortified by a titanium coating (a surface layer that reduces friction and boosts heat, corrosion, and rust resistance). The hex shank locks into impact drivers and quick-change chucks without slipping — a real advantage over the round-shank bits elsewhere on this list.
The versatility is what owners love, calling it “handy around the house” and praising the aluminum storage box as far better than a flimsy plastic sleeve. The spiral flute design keeps metal chips from flying and clears them faster, which means smoother drilling without overheating the material. For aluminum plates and general shop work, customers note clean cuts without problems.
The honest cloud here: sharpness and durability get mixed reviews. Some owners find the bits dull quickly or break on first use in metal, with the harshest note being that they smoked without cutting on tough material. These are best treated as light-to-medium metal and wood bits, not dedicated hard-steel breakers — for heavy stainless, the twist-drill sets above are the stronger bet.
Reach for this if: You want one hex-shank tool that handles a wide range of hole sizes in softer metals and wood.
Look elsewhere if: Your daily work is hardened steel — the twist bits in this guide cut deeper and last longer.
Understanding the Specs
M35 Cobalt Content
M35 is a high-speed steel with 5% cobalt mixed into the alloy. Cobalt raises the temperature at which the steel softens, so the cutting edge keeps its hardness when friction heats the metal. That warmth resistance is why cobalt bits cut stainless and hardened steel that dull plain HSS instantly.
135° Split Point
Standard drill points have a flat chisel edge that skates across hard surfaces. A split point (also called self-centering) has a secondary grind that creates a sharp cutting edge right at the tip. That lets the bit bite into the metal immediately, so you get precise starts without a pilot hole.
FAQ
How is M35 cobalt different from regular HSS drill bits?
Can cobalt drill bits handle hardened steel bolts and studs?
Why does my drill bit keep walking or skating on metal?
How fast should I run cobalt bits in a drill?
Can I use cobalt bits in a regular power drill or only a drill press?
What size cobalt drill bit set should I buy first?
Are cobalt bits good for wood and plastic too, or just metal?
What is the difference between M35 and M42 cobalt steel?
Why do some cobalt bits break even when used correctly?
Final Thoughts: The Verdict
For most people, the cobalt drill bits for metal winner is the RCINDUS 15-piece set because it pairs the strongest value-for-money reputation with enough bits to cover everyday work. If you want the full 1/16-to-1/2-inch range and pro-level coverage, grab the STROTON 17-piece kit. And for big 1/2-inch holes in thick steel plate, the Narwhal 3-pack is the one to reach for — the crowd favorite among them holds a 4.6-star score from 800+ owners, which tells you the quality holds up in real shops.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of August 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
As an Amazon Associate, FitlyFast earns from qualifying purchases. This does not affect which products we feature.