Most people buy a twist drill set once, assume it will handle anything, and then discover the hard way that a wood bit dulls in three holes through steel. If you have been reading spec sheets wondering which alloy actually matters, the short answer is simpler than the marketing: for most metalwork, an M35 or M42 cobalt set with a 135 degree split point and a three-flat shank covers nearly everything a workshop sees. The details below are where the real differences sit, and they are bigger than most people expect.
That is why the best drill bit sets for metal are not all built the same. Two sets can both print “cobalt” on the case and behave completely differently on stainless steel, because one is 5% cobalt and the other is 8%, and because one has a split point while the other has a conventional point that walks across the workpiece. We looked at ten sets that cover the range from a 13-piece budget add-on to a 29-piece professional shop set, and sorted them by the metal you are most likely to actually drill.
A quick note on power tools: bit choice and machine choice go together, and a rigid machine changes what a bit can survive. If your work involves bigger holes or repeat production, our guide to drill presses for home workshops is worth a look. For handheld-only work, the cordless setups in our cordless drill combo kit roundup pair well with the mid-size cobalt sets below.
Top 3 Picks: Best Drill Bit Sets for Metal (October 2026)
These three cover the widest range of real jobs. The Bosch CO14 is the safest single purchase, the CO21B is the one to reach for when stainless and heat are the problem, and the HURRICANE set is the volume pick when you want every common size in one box.
Bosch CO14 Cobalt 14-Pc Set
- Cobalt HSS jobber bits
- Split-point no-skate tip
- Three-flat shank 3/16 in and up
- 1/16-1/2 in range
Bosch CO21B M42 21-Pc Set
- 8% cobalt M42 alloy
- Surface-hardened tip
- Thick web-helix design
- Case included
HURRICANE 99-Pc Titanium-Coated Set
- 99 pieces with heavy duplicates
- 135 degree self-centering point
- 1/16-3/8 in sizes
- Divided storage case
Best Drill Bit Sets for Metal in 2026
Every set below appears in this table with its alloy, point design, shank and the metal it handles best. The full reviews follow in the same order.
| Product | Specifications | Action |
|---|---|---|
| Bosch CO14 14 pc. Cobalt Metal Drill Bit Set |
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Check Latest Price |
| Bosch CO21B 21-Piece Cobalt M42 Set with Case |
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 STROTON Metric M42 8% Cobalt Set 1-10mm 19pcs |
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| HURRICANE 99-Piece Titanium-Coated HSS Twist Drill Set |
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 DEWALT DWA1240 14-Piece Cobalt Alloy Steel Set |
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 MACXCOIP 13-Piece M35 Cobalt HSS Jobber Set 1/16-1/4 in |
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 IRWIN 29-Piece M35 Cobalt Alloy Steel Set 3018002 |
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 Drill America DWD29J-CO-PC 29-Piece M35 Cobalt Set |
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 WildBossy 20-Piece M35 Cobalt Jobber Set 1/16-1/2 in |
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 LingGan 13-Piece M35 Metric Cobalt Set 1.5-6.5mm |
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How We Picked These 10 Sets
Every set here has to state its alloy grade in writing, not just show a colour. M35 is 5% cobalt and M42 is 8%, and a set that never names its grade tells you nothing you can verify later.
From there we weighted four things: point design, shank type, whether the size range matches the sizes people break most often, and whether the case keeps the set organised. We also pulled review volume and the complaints buyers repeat, because a set with a large owner base tells you far more about failure modes than a set with fifty reviews. Where reviews conflict with the listing, we flagged the conflict rather than repeating the claim.
1. Bosch CO14 14 pc. Cobalt Metal Drill Bit Set – Best Overall for Stainless and Mild Steel
Bosch CO14 14 pc. Cobalt Metal Drill Bit Set
Cobalt HSS jobber bits
135 degree split-point tip
Three-flat shank 3/16 in and up
1/16-1/2 in range
14 pieces
Pros
- Cobalt construction holds a point over repeated use
- Split-point tip starts without skating
- Three-flat shank grips larger bits
- Clean cuts in aluminum mild steel and 316 stainless
Cons
- Drilling speed is average rather than exceptional
- Dulls quickly on very hard or highly abrasive steels
That is the set we keep coming back to. The CO14 combines a split-point tip, a three-flat shank on everything from 3/16 inch upward, and a 135 degree cutting angle, which solves the two complaints we hear most: the bit skating on the start, and the bit spinning in the chuck under load. It runs from 1/16 inch to 1/2 inch with duplicates of the common fractions, so the sizes that snap most often have a spare.
Owners report clean, fast cuts in aluminum, mild steel and 316 stainless, and the set has a strong following for automotive bolt and fastener removal, where a split point earns its place because you cannot always centre the bit on a stripped head. The bits are built for very high drilling temperatures, which is the specification line that matters when pushing through stainless.
The honest limitation is heat resistance on the hardest steels. This is a cobalt set, not a carbide one, and buyers drilling case-hardened or heavily abrasive material report that the bits dull faster than they hoped. On very hard stock the surface-hardened tips in the Bosch M42 set at number two are the better tool.
Drilling speed is the other thing reviewers mention as merely average rather than exceptional. That is a function of the 14 piece range being modest, not of the metallurgy, and it is the trade-off for a set that stays sharp in ordinary workshop steel without a lot of attention.
What the 14-piece size range means for real jobs
With duplicates of the common fractions included, this set is built around the sizes that actually break. If you are stepping up to 5/8 inch or larger, you will need to source those separately, and the three-flat shank advantage is worth paying up for when you do.
For anyone who drills into stainless regularly, the split-point start removes the need for a centre punch on most work. That single feature saves more ruined workpieces than any coating on the list.
Where it falls short of the heavy-duty sets
If your work is mostly hardened or case-hardened steel, the alloy here will not keep pace. The CO14 is built for the broad middle of the metal spectrum, and the number two set exists for the harder end of it.
It is also a 14-piece box. If you want every fraction between 1/16 and 1/2 in, the 29-piece sets at numbers seven and eight give you considerably more reach for the same job.
2. BOSCH CO21B 21-Piece Cobalt M42 Set – Best for Stainless Steel and Heat
BOSCH CO21B 21-Piece Assorted Set with Included Case Cobalt M42 Metal Drill Bit with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, Light-Gauge Metal, Aluminum
M42 alloy with 8% cobalt
Surface-hardened tip
Thick web-helix design
Split point 1/8 in and up
21 pieces with case
Pros
- M42 alloy holds an edge on stainless cast iron titanium
- Thick web-helix resists flex and breakage
- Split point removes need for centre punching
- Storage case included
Cons
- Dulls on extremely hard case-hardened steel
- Needs slow speed and cutting fluid to shine
This is the alloy upgrade that answers the most-asked question on this topic. M42 contains 8% cobalt against 5% in M35, and the manufacturer claims roughly ten times the life of standard bits. The practical version of that claim is that the edge survives the heat build-up that comes with stainless steel and cast iron, where a standard cobalt set starts to glaze over.
The construction details are as deliberate as the alloy. A thick web-helix design resists the torsional flex that snaps bits on hard stock, a surface-hardened tip is ground to penetrate abrasive material, and split points on everything 1/8 inch and up plus three-flat shanks on 3/16 inch and up cover both the start and the grip problems. Users report cutting through thick steel plate in under a minute per hole with cutting fluid.
Buyers are specific about the operating envelope. This set wants low speed and cutting fluid, and it wants both. Run it fast and dry and you are back to the dulling the extra cobalt was meant to solve, which is a common disappointment in reviews of nearly every premium set.
The other recurring note is that the bits can still burn out on very hard or case-hardened steel. More cobalt means more heat resistance and more brittleness at the same time, so this is a real trade-off rather than a straight upgrade in every direction.
Choosing between the two Bosch sets
The CO21B is the one to buy if stainless, cast iron or titanium is a regular part of your work. The CO14 is the one to buy if you mostly drill mild steel and aluminium and want the set to stay sharp with less fuss.
The size range also differs. This set runs from 1/16 inch through 1/2 inch with duplicates, which is a wider spread than the CO14 at the upper end of the common workshop sizes.
What to watch when using it
Slow speed plus cutting fluid is not optional here; it is how the alloy is meant to be used. Without both, you will hear complaints about dulling that are really technique complaints.
Because 8% cobalt is harder than 5%, feed it steadily rather than leaning on it. A sudden change of direction on a thick plate is where the harder alloy is most likely to snap.
3. STROTON Metric M42 8% Cobalt Set 1-10mm 19pcs – Best for Hardened Steel
Metric M42 8% Cobalt Twist Drill Bits Set for Stainless Steel and Hard Metal (1mm-10mm/19pcs)
M42 steel rated 68-70 HRC
19 pieces 1-10 mm
0.5 mm increments
135 degree split point
Straight shank
Pros
- 8% cobalt cuts hardened steel and stainless cleanly
- Full metric coverage in 0.5 mm steps
- Stepped cutting edge survives high-tensile bolts
- Manufacturer lifetime replacement warranty
Cons
- Smaller sizes can snap on hardened steel
- Size markings are small and hard to read
- Case latch is flimsy
This is the only set in the group that publishes a hardness figure: 68-70 HRC. That number separates a real M42 claim from a marketing one, and it also shows where the limit sits. Owners use it on hardened steel and stainless and report that the stepped cutting edge holds up against high-tensile bolts that would walk a lesser set.
The 19 pieces cover 1 mm to 10 mm in 0.5 mm increments, filling the gap between the coarse fractional sets and the small metric set at number ten. A three-step cutting geometry lifts long chips rather than grinding with a blunt edge, the straight shank fits standard chucks, and the manufacturer lifetime replacement warranty is repeatedly singled out as the reason to buy this over a generic set.
Brittleness is the trade-off with 8% cobalt, and this is where it shows. Buyers working hardened steel report that the smallest diameters can snap, exactly the failure pattern a cobalt brittleness warning predicts. Size markings are also described as small and hard to read at a glance, which costs time when you are hunting for one specific bit.
The case is another recurring complaint: the latch is flimsy, so treat it as transport protection rather than a home for loose bits.
What the 0.5 mm increments actually solve
Metric work rarely lands on a convenient size. Half-millimetre steps from 1 mm to 10 mm mean you can hit a fastener clearance diameter directly instead of stepping up and tearing out the hole edge.
For anyone working in a shop that mixes metric fasteners with fractional stock, that range is the reason to own this set rather than a larger fractional one.
Where the hardness rating gets tested
The 68-70 HRC figure is a real edge-retention claim, not a toughness claim. On the smallest diameters in the set, it means a snap is more likely than a slow dull-down.
If your work is mostly large-diameter hardened work, take the larger sizes from this set and the smaller pilot sizes from a metric M35 set at number ten.
4. HURRICANE 99-Piece Titanium-Coated HSS Set – Best Value for Wood, Plastic and Soft Metal
99 Pieces Titanium Twist Drill Bit Set, 135° Tip High Speed Steel, Size from 1/16″ up to 3/8″, Ideal Drilling in Wood/Cast Iron/Aluminum Alloy/Plastic/Fiberglass, with Hard Storage by HURRICANE
99 pieces 1/16-3/8 in
Titanium-coated high speed steel
135 degree point
Divided plastic case
Pros
- Huge quantity with heavy duplication in small sizes
- Duplicates in the sizes that break most
- Sharp out of the box with good chip clearing
- Case with dividers keeps sizes sorted
Cons
- Not a cobalt set so it is a step below on stainless and hardened metal
- Small bits break relatively quickly under heavy use
- Size range stops at 3/8 inch
Be clear about what this is. It is a high speed steel set with a titanium coating, not a cobalt set, and no amount of gold-coloured surface treatment changes that. What it is, however, is the best filler for ordinary drilling in a home shop: wood, plastic, aluminium, mild steel, cast iron and fiberglass.
The 99 pieces are distributed sensibly, with 16 of the 1/16 inch, 16 of the 5/64 inch, 15 of the 3/32 inch, 10 of the 7/64 inch, 10 of the 1/8 inch and smaller counts beyond that. The tiny bits that snap on a first mistake are effectively disposable, and a 135 degree point self-centres and penetrates with less pressure than a conventional point. The titanium coating reduces rusting and heat build-up, and the case has top and bottom dividers.
Buyers treat it as a bulk general-purpose set and judge it on that basis: strong value, sharp on arrival, and never short of a replacement for a broken bit. The same 99-piece configuration is also offered in larger 230 and 276-piece variants if you want the same approach with more coverage.
Where it is a step below is on the harder end of metals. Because the core is HSS rather than cobalt, it dulls on stainless and hardened steel where a cobalt set would keep going, and the smallest bits break relatively quickly under heavy use in metal.
When a 99-piece set beats a 13-piece set
Size coverage is the whole argument. If you work across wood, plastic, sheet metal and light fabrication in the same week, a set with duplicates in every small fraction removes the most common annoyance in a metal shop, which is running out of the size you need.
You give up the larger sizes, because the range stops at 3/8 inch. Anything above that comes from a cobalt set in this roundup.
What the titanium coating does
The coating resists rusting and reduces heat build-up on the cutting edge. It is a surface treatment, not an alloy upgrade, so it improves what a high speed steel bit can do without changing what it fundamentally is.
Keep this set in the drawer for general work and put your stainless and hardened drilling on a cobalt set with a stated grade.
5. DEWALT DWA1240 14-Piece Cobalt Alloy Steel Set – Best for Sheet Metal and Stud Drilling
DEWALT Cobalt Alloy Steel Drill Bit Set with Pilot Point, 14-Piece (DWA1240)
Cobalt alloy steel
Pilot point on larger diameters
135 degree spiral flute
Clear-lid case with clip latch
14 pieces
Pros
- Stays sharp through long shop sessions
- Cuts clean round holes in sheet metal and studs
- Clear-lid case with a clip latch
- Bits connect to ToughCase storage
Cons
- Pilot point appears on larger sizes only
- Smaller bits clog when drilling deep holes
- Fractional sizes only with no metric coverage
Where the Bosch sets lead with the split point, this one leads with the pilot point, and that difference matters most on thin material. A pilot point pushes the bit into the surface before the cutting lips engage, so on sheet metal it starts without the skating you get from a conventional point. Users report clean round holes in mild steel, stainless and sheet metal without forcing the drill.
The cobalt alloy steel holds its edge through long sessions, which is why this shows up in furniture assembly, HVAC and general shop work where the same sizes get used day after day. The storage is the part we like best: a patented bit-bar design inside a clear-lid case with a clip latch, and it connects to ToughCase storage so it shares a box with your other bits rather than becoming one more loose case.
The pilot point is on the larger diameters only, and the smallest bits are conventional. On thin-gauge material where you are drilling by eye, that is worth knowing before you blame yourself for a walked start.
Chip clearing in the small sizes is another recurring complaint, along with the absence of any metric coverage and no 1/2 inch size in the set. The case plastic feels less robust under heavy shop use than the metal-trimmed cases on the professional sets.
Why the pilot point suits sheet metal
A pilot point is a mechanical starting aid, not a cutting geometry change. It engages the workpiece before the full cutting lips do, which is what stops a slick thin surface from skating sideways and marking it.
For anyone drilling holes in sheet metal for hardware, that is a better use of a set than a larger range of sizes you will rarely touch.
What to check before you buy
Confirm the sizes match your work. This set is SAE fractional only, so if you work in metric you will need a different box entirely, not a supplement.
It also stops below 1/2 inch. If your project needs larger holes, the 29-piece sets at numbers seven and eight cover the range without a second purchase.
6. MACXCOIP 13-Piece M35 Cobalt HSS Jobber Set – Best Budget Backup Set
MACXCOIP 13Pcs(1/16″-1/4″) Cobalt Drill Bit Set M35 HSS Jobber Length
M35 cobalt HSS
1/16-1/4 in fractional sizes
135 degree self-centering point
Indexed storage case
13 pieces
Pros
- A cobalt set without a name-brand premium
- Larger bits cut mild steel and stainless readily
- Self-centering tip reduces walking on thin stock
- Indexed case keeps sizes labelled
Cons
- Smallest bits skate or snap on stainless
- Case is cheap and does not latch securely
- Case size labelling can be misleading
This set exists for a specific job: having a spare cobalt set that lives in the van or the toolbox drawer. Thirteen pieces from 1/16 inch to 1/4 inch, M35 cobalt HSS, a 135 degree self-centering spear point and a fully hardened and polished cutting edge. Owners use the larger bits to drill out broken screws and stripped fasteners, which is arguably the most common reason a workshop ends up drilling into hardened material in the first place.
It is worth knowing that this brand sells the same core set in 10, 21, 29, 115 and 234-piece configurations, so the 13-piece box is the smallest of the family rather than a unique product. The index case has size labels, which matters when you are hunting for 11/64 inch in a drawer.
The honest limitation is the small end of the range. Buyers consistently report that the smallest bits do not bite into stainless and will skate or snap, and some report bits failing to cut the very metal the set was bought for. That is the expected behaviour of a budget cobalt set rather than a defect, but it is why we do not rate it higher.
The case is the most common complaint across reviews: cheap plastic that does not latch securely, and labelling that can be misleading. Treat it as a carrier rather than a storage system.
Where a budget cobalt set earns its place
A generalist who does not know what metal is coming next still needs a cobalt set. This is the smallest cobalt box in the roundup, and the 1/16 to 1/4 inch range covers the sizes most likely to be needed for fasteners, brackets and hardware.
For broken-fastener work the larger bits are genuinely useful, because extracting a snapped bolt means drilling through hardened material and then working the bit sideways, which is where chip clearing matters more than alloy grade.
Why the small bits disappoint
A 1/16 inch cobalt bit has very little metal behind the cutting lips. On soft stock it is fine; on stainless it lacks the cross-section to survive the twisting load, and it will skate first and snap second.
Buy a set with more of those small sizes if the small sizes are what you actually work in, and accept that the alloy claim says nothing about the diameter.
7. IRWIN 29-Piece M35 Cobalt Alloy Steel Set – Best for 1/64 Inch Increment Coverage
IRWIN Drill Bit Set, M35 Cobalt Alloy Steel Steel, 29-Piece (3018002)
5% cobalt alloy steel
29 pieces 1/16-1/2 in
1/64 in increments
135 degree split point
Heavy duty web
Pros
- 5% cobalt for heat and abrasion resistance
- Full 1/64 in increments from 1/16 to 1/2 in
- Heavy duty web construction on hard alloy steel
- Split point minimizes walking
Cons
- Charges a premium over comparable 29-piece sets
- Case storage is required to keep the range organised
The reason to buy this set over another 29-piece box is the increments. Twenty-nine pieces from 1/16 inch to 1/2 inch in 1/64 inch steps gives you every fractional size in the common range, with nothing skipped. If you work to a drawing that specifies 23/64 inch rather than 7/32 inch, this is the set that has it, and IRWIN also builds a five-piece version of the same bits for reverse-direction work.
Construction is the second argument. A heavy duty web adds material at the exact spot where bits fail, the neck of the bit just behind the flutes, and owners credit that with durability on hard alloy steel. The 135 degree split point handles the start, and the case keeps 29 sizes from becoming 29 loose bits.
The reviews are enthusiastic about the alloy and the range, and the single recurring drawback is cost. It sits at the top of this group, and owners who rate it that way generally describe it as a professional-grade set bought once rather than a routine purchase.
It is also not the strongest choice for extreme heat. This is 5% cobalt M35, so for stainless work under sustained load the 8% M42 set at number two has more headroom.
Why the heavy duty web matters
Web thickness is the difference between a bit that dulls and a bit that snaps. A thicker web resists the flex that happens when a bit is fed off-centre or when a workpiece springs back as the hole breaks through.
That makes this a better set for hand drilling on hard alloy steel than a comparable set with a standard web, where the same mistake costs you a snapped bit instead of a bent one you can still use.
What you give up compared with the cheaper 29-piece sets
You pay more for the same piece count and roughly the same size span, so the justification is the alloy, the web and the 1/64 inch completeness. If you only need 1/32 inch steps, the value case for a premium set is much weaker.
We would pair it with a second, general-purpose set for rough work, which is the two-set strategy people in forums recommend and which suits the quality gap here.
8. Drill America DWD29J-CO-PC 29-Piece M35 Cobalt Set – Best for Drill Press Work
Drill America – DWD29J-CO-PC 29 Piece M35 Cobalt Drill Bit Set in Round Case (1/16″ – 1/2″ X 64ths), DWDCO Series
M35 cobalt jobber bits
Gold oxide finish
135 degree self-centering split point
1/16-1/2 in in 1/64 in steps
Round case
Pros
- Cobalt steel outlasts HSS on hard materials
- Gold oxide finish cuts friction and heat
- Split point works without a pilot hole
- Meets ANSI specifications
Cons
- Higher cost than comparable 29-piece cobalt sets
- Best suited to a drill press and steady feed rather than hand drilling
This is the set for a rigid machine. The round case holds all 29 jobber-length bits from 1/16 inch to 1/2 inch in 1/64 inch steps, and the bits are built to ANSI specification, which matters if you are producing repeatable holes rather than one-off work. Feedback consistently centres on durability: cobalt steel plus a gold oxide finish gives longer tool life and less heat on the cutting edge.
The chip behaviour is the underrated part. The 135 degree self-centering split point penetrates hard material without a pilot hole and produces small chips, so the flutes stay clear through a deep hole. On a drill press with a steady feed, that is the difference between a bit that evacuates swarf and one that binds.
Two limitations are named directly by owners. The first is cost relative to other 29-piece cobalt sets of the same piece count. The second is suitability: reviewers describe it as best suited to a drill press and steady feed rather than hand drilling, because a rigid setup is what lets the cobalt alloy stay intact.
If your work is handheld and intermittent, this set asks more of your technique than its position in the range suggests, and one of the mid-size sets would suit you better.
What a drill press changes about bit selection
A rigid machine removes the flex that snaps cobalt bits, so you can run a harder alloy and a lower speed without the punishment a handheld drill delivers. It also lets you peck and retract, which clears chips far more reliably than feeding straight through.
That is why the same bits behave differently in a press and in a cordless drill, and why a set described as press-oriented feels disappointing when handheld. Our benchtop drill press picks for hobbyists are worth pairing with this set if you are setting one up.
Why ANSI specification is worth noticing
ANSI specification means the diameter and geometry meet a published standard, so a bit from this set and a bit from another set cut the same hole. That matters when the hole has to fit a fastener to tolerance.
For decorative or one-off drilling it is irrelevant, which is another reason to think about your actual work before choosing between sets at the same tier.
9. WildBossy 20-Piece M35 Cobalt Jobber Set – Best for Broken Fastener Removal
M35 Cobalt Drill Bit Set 20PCS(1/16″-1/2″) High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal with Index Storage Case
M35 cobalt steel with molybdenum
20 pieces 1/16-1/2 in
Three-flat shank
135 degree split point
Titanium surface finish
Pros
- Cuts mild and hardened steel cleanly on a drill press
- Well regarded for snapped bolts studs and taps
- Three-flat shank gives reliable chuck grip
- Compact index case with common fractions
Cons
- Brittle and can snap if pushed aggressively
- Case is lighter duty than ideal
- Hardness falls short on very hard tempered steel
The defining feature is molybdenum in the M35 alloy, which the manufacturer rates to 67 Rockwell, plus a titanium surface finish on a 135 degree split point and a three-flat shank. In practice buyers single out one job above all others: extracting snapped bolts, studs and taps, where the sequence is a pilot hole, then successive step-ups in diameter, then a final bit at the fastener size.
That sequence punishes bits. Stepping up while the bit is still centred puts a lateral load on the web, the condition that snaps an 8% cobalt bit and merely dulls a 5% one. The three-flat shank helps because it resists the bit rotating in the chuck as you apply that sideways force.
The complaints are honest ones. Bits are brittle and can snap if pushed aggressively or run at high speed in a hand drill, the case is lighter duty than ideal, and buyers report performance on tempered steel falling well short of the advertised Rockwell rating. We read that last point as a general caution about hardness claims on tempered material rather than a defect specific to this set.
The titanium surface finish and edge retention also vary with use, which is normal for a coated bit and worth remembering when a coated set appears to lose its bite before a bare one does.
How to drill out a broken fastener without snapping bits
Step up in small increments rather than jumping straight to the fastener diameter, and back the bit out to clear chips every few passes. Each reduction in step size lowers the sideways load on the web.
Keep the drill in straight and let the bit cut rather than pressing. On a press this is where the 67 Rockwell claim earns its keep, and in a handheld drill it is where the brittleness bites.
What the three-flat shank changes
Three flats on the shank give the chuck jaws something to grip that resists rotation under load. On a standard round shank, a bit under heavy feed can slip in the jaws, which chews both the bit and the chuck.
It matters most in exactly the broken-fastener scenario above, where you are deliberately loading the bit sideways.
10. LingGan 13-Piece M35 Metric Cobalt Set 1.5-6.5mm – Best for Small Metric Diameters
Metric Cobalt Drill Bits Set 1.5-6.5mm 13PCS, M35 high speed steel, high hardness straight shank drill, mechanical or hand drill for drilling, suitable for stainless steel, iron, copper and aluminum.
5% cobalt M35 HSS-CO
13 metric sizes 1.5-6.5 mm
Straight shank
0.13 kg
Pros
- Full metric coverage in a compact box
- Clean accurate holes in stainless aluminum copper
- Effective for removing seized exhaust bolts
- Works in hand drills and drill presses
Cons
- Cobalt brittleness snaps small bits at high speed
- Thin plastic case with a damaged cover
- Needs oil and slow speed for good results
Thirteen metric sizes from 1.5 mm to 6.5 mm in 5% cobalt M35 HSS-CO, and that is the entire proposition. Metric fasteners cluster in that range, so a small metric cobalt set covers sizes a fractional set simply does not have. The straight shank fits standard chucks, and the same bits work in a hand drill or a press.
Buyers find them sharp and accurate, and several report repeated drilling through thin stainless and removing long-worn exhaust bolts, which is demanding work for 1.5 to 6.5 mm diameters. The gold-coloured finish is cosmetic rather than protective, and the listing does not claim a coating benefit, which we would rather see than a colour used as a proxy for one. For the same reason, this set is not framed here as the budget pick; the MACXCOIP at number six fills that role.
The warnings are consistent across reviews. Cobalt is brittle, so pushing hard or running fast snaps the small bits, and some bits will not start a hole in thin stainless without a centre mark. The case is thin plastic and a cover can arrive damaged, so inspect it before you rely on it.
Buyers also flag that oil and slow speed are required for good results. On this set that is not a quality complaint, it is the operating instruction.
Filling the gap between fractional and metric sets
Fractional sets and metric sets are not substitutes. A 5/16 inch bit and a 8 mm bit are not the same hole, and a set that stops at 1/4 inch leaves you improvising on anything larger in metric.
This set covers the small end of metric properly. For larger metric work, the 1 mm to 10 mm set at number three is the one to pair with it.
When a straight point is the right choice
A straight point does not self-centre, so it relies on the centre mark. On a flat, marked, small-diameter hole in sheet or plate, that is entirely adequate and it cuts cleanly.
The failure mode is thin stainless, where the bit can skate before it bites. Mark it properly and keep the speed down, and the brittleness warning applies to any small cobalt bit rather than this set alone.
How to Choose a Metal Drill Bit Set
Three specs decide whether a set works on metal: the alloy, the point geometry, and the shank. Everything else on the box is secondary, and the marketing is mostly secondary too.
Material: choose the alloy before the brand
Pick M35 cobalt for general metal, M42 cobalt for stainless and heat, and carbide only in a rigid machine shop.
M35 is 5% cobalt and M42 is 8%, and that single difference decides how much heat the cutting edge survives before it glazes. Plain high speed steel is fine for aluminium, mild steel, wood and plastic, and it is the wrong tool for stainless or anything hardened. Carbide will cut harder material than cobalt, but it is brittle and needs a rigid setup, so a handheld drill that flexes will shatter it. If a listing never states a grade, treat the colour as decoration.
Point angle: 118 degree versus 135 degree split point
A 135 degree split point self-centres and needs no pilot hole, while a 118 degree conventional point bites harder but walks.
The 135 degree point has two cutting lips that cut at the same time, which produces two small chips instead of one large one, keeps the flutes clear, and pushes the bit into the workpiece without wandering. A 118 degree point has a shallower chisel edge that scrapes rather than shears, so it cuts faster on a machine that can hold it steady and needs a centre mark or a pilot hole in a hand drill. A pilot point sits between the two: it engages the surface before the full lips do, which is why it works well on sheet metal.
Shank: why three-flat beats round, and the reduced-shank trap
Three-flat shanks stop the bit spinning in the chuck under load, and every shank must be at least as thick as the bit can be gripped.
A round shank works fine until you load the bit sideways, at which point the jaws slip and you damage both. Three flats give the jaws purchase and resist rotation. The trap to avoid is the reduced shank, where a set lists a 1/4 inch shank across the board and then includes bits that cut 3/8 inch and larger. Those large bits cannot be held properly in a standard chuck, and the larger sizes in the set are effectively unusable without a suitable holder. Check the shank diameter against the largest bit you actually need.
Coating: what the colour does and does not tell you
Colour indicates a surface coating, not an alloy, and a gold bit can be ordinary high speed steel underneath.
Titanium coatings reduce friction, rust and heat build-up on the cutting edge, and black oxide and gold oxide do similar work at a lower level. All of them are surface treatments. They improve what the core material can do and they do not turn HSS into M42, which is why a 99-piece titanium-coated HSS set and an M42 cobalt set look broadly similar in a drawer and behave nothing alike. Judge the core alloy first and treat the finish as a bonus.
Case and size range: what actually matters
A set that does not state its largest bit, or its increment between sizes, is asking you to guess.
Check three numbers before buying: the smallest size, the largest size, and the increment. Increments of 1/64 inch give you every common fraction, which matters on drawing work, while 1/32 inch steps leave gaps. On the case, an index layout with size labels and a real latch beats a flat tray, because loose bits in a tray are lost bits. A case that connects to a modular storage system is a bonus, not a requirement.
Why Metal Drill Bits Snap at the Web
The web is the flat section of steel directly behind the cutting lips, and it is the thinnest, most highly stressed part of the bit. It is also where almost every metal drilling failure happens.
Five causes account for nearly all of it. First, feeding too hard, which bends the bit and puts the load on the web instead of the lips. Second, drilling off-centre, so the bit works against the side of the hole. Third, excessive speed, which generates heat faster than the edge can dissipate. Fourth, a hardened exit face at the bottom of a deep hole, where the bit punches into harder material than it started in. Fifth, chip packing, where clogged flutes lock the bit and the whole torque goes into the web.
The mitigations follow directly. Use a three-flat shank and a keyed chuck so the bit cannot slip. Reduce speed and let the bit cut instead of being pushed. Centre carefully and back the exit face with wood, or step-drill through it. Clear chips by retracting every few passes in deeper holes. And use a thicker web, which is why the IRWIN and Bosch M42 sets in this roundup tend to survive abuse that snaps lighter sets.
Speed, Lubrication and Drilling Steel Without Ruining Bits
Speed matters more than any other variable, and the rule is simple: bigger bits turn slower. For mild steel, roughly 1000 RPM at 1/16 inch falling toward 150 RPM at 1/2 inch. For stainless, drop by about a third. For aluminium, you can run faster and keep the bit cool with a little cutting fluid or even plain water, which works because the metal is soft and heat is not the failure mode.
On hardened steel, drop further still. Below a few hundred RPM the cutting lips stay loaded instead of rubbing, which is the difference between a hole and a polished dimple.
The sequence that works most reliably: centre punch the workpiece, use a split point and skip the pilot hole entirely if your bit has one, start at low speed, add cutting oil, and feed steadily rather than leaning on the bit. For deep holes, retract every quarter inch to clear chips. And when you break through a thick plate, back the exit with a sacrificial piece of wood, because that hardened face is what destroys otherwise good bits.
One safety note worth repeating: no loose gloves near a spinning bit, eye protection always, and clamp the workpiece rather than holding it. A magnetic drill press is a good way to keep both hands free and the work rigid, and our magnetic drill press roundup covers the options for metalwork away from a bench.
Frequently Asked Questions
What drill bit works best on metal?
An M35 or M42 cobalt bit with a 135 degree split point is the best general choice for metal. M35 is 5% cobalt and handles mild steel, aluminium and cast iron well. M42 is 8% cobalt and handles stainless steel, heat and abrasive material better. The split point self-centres, so it starts without skating and needs no pilot hole.
What is a high-quality metal drill bit set?
A high-quality set states its alloy grade in writing, uses a 135 degree split point, fits three-flat shanks on the larger bits, lists its smallest and largest sizes with the increment between them, and stores the bits in an indexed case with labels. Sets that only describe themselves as heavy duty or show a gold colour are telling you nothing verifiable.
Is titanium or cobalt better for drilling steel?
They are not alternatives, because titanium is a coating and cobalt is part of the core alloy. Cobalt determines how much heat and wear the cutting edge survives, so it decides whether the bit can drill stainless or hardened steel. A titanium coating adds surface hardness, rust resistance and lower friction, and it makes an HSS bit better without making it a cobalt bit.
Which brand of cobalt drill bits is the best?
The answer depends on the job rather than the brand. Bosch is the strongest all-round choice, with the CO14 as a balanced generalist and the CO21B M42 for stainless. Drill America suits drill press work with ANSI-spec construction. IRWIN offers the most complete 1/64 inch fractional range. STROTON and Drill America cover metric work in 8% and 5% cobalt.
Are cobalt drill bits good for stainless steel?
Yes, and 8% cobalt is meaningfully better than 5% on stainless because stainless work generates sustained heat at the cutting lip. The Bosch CO21B and the STROTON M42 set are both 8% cobalt. Both need slow speed and cutting fluid, and both are more brittle than a 5% set, so feed them steadily rather than forcing them.
Is there a drill bit stronger than cobalt?
Tungsten carbide is harder than cobalt and will cut harder material, but it is brittle and needs a rigid setup. A handheld drill flexes enough under load to shatter a carbide bit, which is why most people who try carbide in a hand drill conclude it is worse. For handheld work, moving from 5% to 8% cobalt is the safer upgrade.
Why won’t my drill bit go through metal?
The usual causes are running too fast, feeding too hard, using a wood or general-purpose bit, drilling off-centre, or letting chips pack the flutes. Metal generates far more heat than wood, so a bit that is dull rather than broken is usually a speed problem. Drop the speed, add cutting oil, centre the workpiece and retract periodically to clear chips.
Final Verdict: The Best Drill Bit Sets for Metal in 2026
The Bosch CO14 remains our pick as the best drill bit set for metal overall, because a split point, a three-flat shank and cobalt construction solve the two problems that ruin most workshop drilling. Buy the Bosch CO21B instead if stainless and heat are your normal workload, the STROTON set for hardened steel in metric, and the HURRICANE 99-piece box for volume general-purpose work.
Whatever you choose, judge it on three things: the stated alloy, the point geometry and the shank. Ignore the colour. Our router bit set guide covers the woodworking side of the same question.