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Drilling into stainless steel is one of the toughest jobs you can hand a drill bit. The metal is hard, it work-hardens if you overheat it, and a standard bit will just skate across the surface or dull after a few holes. The right bit for this job needs specific cobalt content, a sharp point that won’t wander, and the heat resistance to survive the friction. This guide breaks down seven sets that actually handle stainless, explained in plain terms so you know exactly which one to reach for.
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.
Every pick here uses 5% cobalt HSS steel (high-speed steel with cobalt for heat resistance) and a 135-degree split point (a tip shape that bites into metal without wandering), so you get a bit for drilling stainless steel that stays sharp instead of dulling fast like a basic hardware store bit.
Quick Picks
- Drill America 15 Piece M42 Cobalt Drill Bit Set — Professional Grade
- WildBossy M35 Cobalt Drill Bit Set 20PCS — Best All-Rounder
- RCINDUS 15PCS 1/4″ Cobalt Drill Bit Set — Best Value
- LU&MN M35 Jobber Drill Bits 1/4″ 10-Piece — Compact Performer
- BECOLLO 11/32 Inch Cobalt Drill Bit Set, 5-Piece — Large-Diameter Value
- STROTON Cobalt Drill Bit Set — Budget-Friendly Start
How To Choose The Best Bit For Drilling Stainless Steel
Stainless steel is abrasive and generates heat fast. If you pick a standard high-speed steel bit, you will likely end up with a dull tip and a ruined workpiece. Here is what matters when you are shopping specifically for stainless.
Cobalt Content — The 5% Rule
The material that makes a bit suitable for stainless is cobalt added to the steel. A 5% cobalt content (often labeled M35) is the baseline for handling hard metals. The cobalt lets the bit stay hard even as friction heats the tip, so it keeps cutting instead of annealing (softening) mid-hole.
The Split Point Matters More Than Coating
A 135-degree split point is a standard feature on every bit in this list. Instead of a flat tip that wanders, the split point has a chisel edge that bites immediately. This means you do not need to center-punch as hard or fight the bit skating across a polished stainless surface.
Quick Comparison
| Model | Best For | Material | Number of Pieces | Size Range | Amazon |
|---|---|---|---|---|---|
| Drill America M42 Cobalt Set | Heavy-duty professional use | M42 (8%) Cobalt | 15 | 1/16″ – 1/2″ | $88.01Amazon |
| MACXCOIP Metric 25Pcs M35 Set | Metric-sized precision work | M35 (5%) Cobalt | 25 | 1.0mm – 13.0mm | $65.98Amazon |
| WildBossy M35 20Pcs Set | Wide fractional range in one case | M35 (5%) Cobalt | 20 | 1/16″ – 1/2″ | $27.99Amazon |
| RCINDUS 15Pcs 1/4″ Cobalt Set | Multiple 1/4″ bits for bulk drilling | M35 (5%) Cobalt | 15 | 1/4″ (all same) | $20.99Amazon |
| LU&MN M35 1/4″ 10-Piece Set | Small batch of tough 1/4″ bits | M35 (5%) Cobalt | 10 | 1/4″ (all same) | $19.99Amazon |
| BECOLLO 11/32″ Cobalt 5-Piece Set | Large-diameter holes in plate steel | M35 (5%) Cobalt | 5 | 11/32″ (all same) | $17.99Amazon |
| STROTON Cobalt 13-Piece Set | Entry-level price, solid performance | M35 (5%) Cobalt | 13 | 1/16″ – 1/4″ | Amazon |
In-Depth Reviews
1. Drill America 15 Piece M42 Cobalt Drill Bit Set (1/16″ – 1/2″)
$88.01as of Jul 15, 3:45 PMThe over-engineered set that handles Inconel and titanium without flinching.
This is the only set in the lineup made with M42 cobalt steel, which contains 8% cobalt — higher than the 5% in M35 bits. That extra cobalt gives it higher “red hardness,” meaning it stays hard at higher temperatures , according to the manufacturer. The 135-degree split point is standard, but the material is what makes this a different class of tool. It is manufactured to National Aerospace Standard 907, so it is built for demanding shops, not light DIY.
Buyers report that these bits throw nice chips and last a long time when used with cutting oil on a drill press. One reviewer noted accidentally ruining a 5/32″ bit by leaving a hammer drill in hammer mode, and Drill America still sent a free replacement despite having no formal warranty — a rare level of support. The set includes 15 sizes from 1/16″ to 1/2″ in 32nds increments, stored in a round metal case. The catch is the higher upfront cost and the fact that the smaller bits can arrive with a chipped tip, as one buyer mentioned.
The Tough-Metal Edge
- 8% cobalt (M42) handles high-tensile materials like Inconel and titanium
- Speeds up to 30% greater than standard HSS
- Manufactured to NAS 907 standard
- Owners mention excellent durability and chip formation
Watch For
- Premium price — the highest in this guide
- Smaller bits can arrive with chipped tips
- No formal manufacturer warranty
Reach for it if: you regularly drill hardened stainless, titanium, or aerospace alloys and need a bit that keeps cutting without degrading.
Look elsewhere if: you only need occasional holes in thin stainless and want a more budget-friendly set without the premium cost.
2. WildBossy M35 Cobalt Drill Bit Set 20PCS (1/16″-1/2″)
$27.99as of Jul 15, 3:45 PMA 20-piece bridge set that covers almost every fractional size you will ever grab for.
This set runs from 1/16″ all the way up to 1/2″, including duplicates of the smaller sizes (two each of 1/16″ through 1/8″). The bits are M35 cobalt steel with a titanium surface finish and a three-flat shank that prevents the bit from spinning in the chuck. One owner reported these went “right through” thin stainless steel without hesitation, and another reported drilling out snapped taps and studs in turbo housings. The 135-degree split point is present for self-centering.
Unlike the RCINDUS set below which focuses on a single 1/4″ size in bulk, this gives you a broad range. Customers note that around half the set cut well, but a few bits in one reviewer’s kit were dull or snapped early — a sign of some quality variance at this price tier. The 15.2-ounce weight feels substantial in the hand.
Broad Coverage
- 20 bits from 1/16″ to 1/2″ — the widest fractional range in the list
- Three-flat shank prevents chuck slippage
- Buyers confirm it cuts thin stainless well
Inconsistent Bits
- Some users report dull bits or snapping on the first use
- Quality control seems uneven across the set
Grab it if: you want a single set that covers most fractional sizes from tiny to half-inch without buying individual bits.
skip it if: you need guaranteed consistency on a critical job — inspect each bit before use.
3. RCINDUS 15PCS 1/4″ Cobalt Drill Bit Set
$20.99as of Jul 15, 3:45 PMFifteen identical 1/4″ bits that cost less than three singles from a big box store.
This is an unusual set: all 15 bits are the same size — 1/4″ in diameter, 6.35mm. That makes it a terrible general-purpose set but a brilliant choice if you need to drill a high volume of 1/4″ holes in stainless. The bits are M35 cobalt steel with a 135-degree split point and the manufacturer says diameter accuracy is controlled within -0.03mm. One customer observed each bit handled about 25 stripped screw heads before dulling, outperforming a single Milwaukee bit that cost on its own.
The obvious trade-off is that you only get one size. But at this price, having 15 copies means you can burn through bits without worrying about cost — a real advantage when drilling through hardened steel where a single bit might not finish a job. Directly operated factory means you skip a middleman markup.
High-Volume Specialist
- 15 bits all 1/4″ — ideal for bulk drilling of one size
- Reviewers point out outlasting premium single bits
- Diameter accuracy within -0.03mm
One-Trick Pony
- No size variety — only 1/4″ bits
- Will not help if you need a different diameter
Buy it when: your project calls for a lot of 1/4″ holes in hard metal — think drilling out bolts or mass-producing pilot holes.
Do not get it if: you need a range of sizes or only drill a few holes now and then.
4. LU&MN M35 Jobber Drill Bits 1/4″ 10-Piece Set
$19.99as of Jul 15, 3:45 PMTen sharp 1/4″ bits that one buyer used to drill all 8 holes in a John Deere bucket without dulling.
Like the RCINDUS set above, these are all 1/4″ bits, but this is a smaller 10-pack. They are M35 cobalt steel (a cobalt alloy that resists heat) with a titanium nitride finish (a coating that reduces friction) and a fully ground flute (a smooth groove that clears metal chips), so the bit stays cool and cuts cleanly. One buyer reports drilling 8 holes in a John Deere bucket to attach hooks and D-ring brackets using a single bit — and it was just as sharp on the eighth hole as the first. Another reviewer said they “cut right through stainless” as long as you avoid overheating, which is the standard rule for stainless work.
The difference between this and the RCINDUS set is that the LU&MN bits have a titanium nitride coating, which gives extra lubricity (less friction). One buyer did report the smallest bit broke after a minute, so they are not indestructible. If you want 10 copies of 1/4″ rather than 15, this is a solid alternative.
Sharp and Rugged
- Titanium nitride coating reduces friction
- Buyers confirm they stay sharp through multiple holes in hard metal
- Good value for 10 bits of the same size
Watch The Smallest Bit
- One user highlighted the smallest bit broke within a minute
- Only one size — 1/4″
Choose this if: you want 10 sharp 1/4″ cobalt bits with a friction-reducing coating and do not mind a slightly smaller pack than the RCINDUS set.
Pass if: you need a few more bits for the money — the 15-pack from RCINDUS gives you more for only a small bump in cost.
5. MACXCOIP Metric 25Pcs M35 Cobalt Drill Bit Set (1.0mm-13.0mm)
$65.98as of Jul 15, 3:45 PMThe only metric set here — 25 sizes from 1mm to 13mm in 0.5mm steps.
If you work in metric, this set is a rare find. It includes every half-millimeter size from 1mm through 13mm, which covers most common tap drill sizes and precision holes. The bits are M35 cobalt steel with a 135-degree split point for self-centering. A former CNC machinist who reviewed the set called them “good quality cobalt drills.” The drill case has indexed slots so you can put each bit back in its correct spot. It weighs 1 pound, so it has a solid feel, and the metal storage box keeps everything organized.
The main limitation is that the highest cobalt content here is M35, not M42, so it is not ideal for extreme aerospace alloys. One reviewer had a bit slip in the chuck and damage the shank, suggesting the steel may not be the toughest available. This set is for metric-focused work on stainless, cast iron, and softer metals.
Comprehensive Metric Range
- 25 bits from 1mm to 13mm in 0.5mm increments
- Indexed metal storage case
- Former machinist reviewer confirmed good quality
Not For Extreme Hardness
- M35 (5%) cobalt — less heat resistance than M42
- One shopper added shank damage from chuck slippage
Get it if: you work in metric and need a full range of sizes for stainless and cast iron, from tiny precision holes up to 13mm.
Look elsewhere if: you work in fractional inches or need the extreme hardness of M42 cobalt for high-tensile alloys.
6. BECOLLO 11/32 Inch Cobalt Drill Bit Set, 5-Piece
$17.99as of Jul 15, 3:45 PMFive identical 11/32″ bits that one buyer used to drill 11 holes through thick plate steel without issue.
This is a focused set: five bits, all 11/32″ (8.57mm). The standout review tells the story best — a buyer needed 12 holes through thick plate steel. An alternate brand with a piloting tip took 2 bits to complete one hole. When they switched to these BECOLLO bits, they said “Wow, 11 holes with these 3 bits, no problem!!!” That kind of real-world endurance is rare. Another reviewer used them to drill through leaf springs on an F150 (hardened steel) and confirmed they worked with slow speed and plenty of oil.
The catch: one reviewer could not get them to penetrate hardened steel, and another said they tend to “walk” slightly when starting a hole — recommending a center punch first. These are not for general drilling, they are a 5-pack of 11/32″ for specific demanding jobs on plate steel or thick metal.
Tough On Plate Steel
- Shoppers say drilling 11+ holes through thick plate steel with one bit
- 5 bits of the same size — good for punishing jobs
- 135-degree split point for self-centering
Not For Tiny Holes
- Only one size — 11/32″
- Some users found they walk without a center punch
Reach for these when: you need to drill a series of 11/32″ holes in thick plate steel or leaf springs — the endurance is real.
Skip if: you need a variety of sizes or work primarily with thin sheet metal.
7. STROTON Cobalt Drill Bit Set (1/16-1/4 Inch, 13PCS)
See price on AmazonThe lowest-cost entry into real 5% cobalt bits, but you get what you pay for in range.
This 13-piece set from STROTON covers 1/16″ to 1/4″ in 1/64″ increments — a decent starter range for small holes in stainless. The manufacturer claims their bits come from their own cobalt mine and deliver “3X heat, wear and chip resistance.” The 135-degree split point and fully ground process are standard. One buyer specifically noted successful drilling on 10.9 hardened steel bolts, recommending that you use oil, slow speed, firm pressure, straight alignment, and clear chips to prevent overheating.
The limitation: the upper size stops at 1/4″, so you cannot drill larger holes with this set. Compared to the WildBossy set which goes to 1/2″, this is noticeably more restricted. For light-duty stainless work or as a backup kit, the price is tough to top. The plastic case is compact at 7 x 3 x 0.69 inches. If you need to drill holes wider than 1/4″, skip this set and go with the WildBossy instead.
Accessible Cobalt
- Real 5% cobalt at a very accessible price
- 13 increments from 1/16″ to 1/4″
- Buyers confirm it works on hardened steel bolts with proper technique
Limited Range
- Maximum size is only 1/4″
- Not as broad as larger sets in this guide
Consider this if: you are on a tight budget but still need real cobalt bits for small holes in stainless — it is the cheapest way to get started.
Move up if: you need sizes larger than 1/4″ or prefer a set with more bits and a broader range.
Understanding the Specs
M35 vs M42 Cobalt Steel
The “M” stands for molybdenum high-speed steel. M35 contains 5% cobalt, which is the minimum needed to drill stainless steel effectively. M42 contains 8% cobalt and offers higher red hardness — meaning it stays hard at higher temperatures — so it can run faster and last longer on tough materials like Inconel and titanium. For most stainless steel work, M35 is sufficient. For repeated heavy use on hardened alloys, M42 is worth the jump.
135-Degree Split Point
Instead of a flat chisel edge that pushes sideways (causing the bit to “walk” across the surface), a split point has a second cutting edge ground into the tip. This lets the bit bite into the metal immediately without a separate center punch. Almost every cobalt bit for stainless has this feature, and it is non-negotiable for getting a clean start on hard, polished surfaces.
FAQ
Can I drill stainless steel with a regular HSS bit?
What speed should I use for drilling stainless steel?
Do I need cutting oil for stainless steel?
What does 135-degree split point mean?
Is M35 cobalt better than titanium-coated bits for stainless?
How long will a cobalt drill bit last in stainless steel?
Will these bits work in a hand drill or only a drill press?
What is the difference between jobber length and stub length?
Can I use cobalt bits on wood or plastic?
How do I stop the bit from walking on stainless steel?
Final Thoughts: The Verdict
For most buyers, the best bit for drilling stainless steel is the WildBossy M35 20-Piece Set because it covers the widest fractional range at a reasonable cost with solid performance on thin stainless. If you need maximum hardness for aerospace alloys or high-volume professional work, upgrade to the Drill America M42 15-Piece Set. And if you only drill 1/4″ holes in bulk, the RCINDUS 15-Piece 1/4″ Set gives you the most bang per bit.
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 July 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.
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