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The best drill bits for stainless steel need more than a hard-looking finish. Common stainless grades can work-harden when a dull bit rubs instead of cutting, so the better choices are cobalt or other manufacturer-documented hard-metal bits paired with correct speed, feed, lubrication, and rigid workholding.
For a compact set, the Bosch CO14B is the strongest all-around pick here. For broader fractional coverage, the Bosch CO21B, DEWALT DWA1269, IRWIN 3018002, Drill America D/A29J-CO-PC, and Chicago-Latrobe 57850 give more sizes for fabrication work.
We did not perform original drilling tests. No hole-count, cutting-speed, heat, or bit-life scores are invented. Manufacturer specifications and current/exact product identities are used.
Quick Picks
- Best compact M42 set: Bosch CO14B — 14-piece M42 cobalt.
- Best larger Bosch set: Bosch CO21B — 21-piece M42 cobalt.
- Best mainstream DEWALT 14-piece set: DWA1240.
- Best DEWALT 29-piece fractional set: DWA1269.
- Best traditional 29-piece M35 set: IRWIN 3018002.
- Best Milwaukee 29-piece set: 48-89-2332 RED HELIX.
- Best M42 industrial value: Drill America D/A29J-CO-PC.
- Best compact Milwaukee RED HELIX set: 48-89-2331.
- Best very large M42 index: Viking/Norseman 69280, 115-piece.
- Best premium USA-made 29-piece set: Chicago-Latrobe 57850.
How We Chose Drill Bits for Stainless Steel
- Material: cobalt-alloy HSS or manufacturer-documented hard-metal construction was prioritized.
- Point geometry: 135° split/Pilot Point-style designs can reduce walking and improve starting control.
- Heat resistance: important because stainless drilling generates substantial heat.
- Chip evacuation: flute geometry matters for reducing rubbing and recutting chips.
- Size coverage: compact sets suit repair work; 29-piece and 115-piece indexes suit fabrication shops.
- Exact product identity: model number and Amazon ASIN had to match before a direct link was added.
Quick Comparison
| Product | Price | Type / Count | Exact ASIN | Best Fit |
|---|---|---|---|---|
| Bosch CO14B | — | M42 cobalt / 14 pc | B07Q9HNTBH | Compact stainless set |
| Bosch CO21B | — | M42 cobalt / 21 pc | B07Q64LTFB | Broader Bosch coverage |
| DEWALT DWA1240 | — | Cobalt / 14 pc | B015J5HU4Y | Mainstream fractional set |
| DEWALT DWA1269 | — | Cobalt / 29 pc | B015J5HVAC | Full fractional index |
| IRWIN 3018002 | — | M35 cobalt / 29 pc | B000BO9JMK | Traditional shop use |
| Milwaukee 48-89-2332 | — | RED HELIX cobalt / 29 pc | B073R8T8QH | Milwaukee hard-metal users |
| Drill America D/A29J-CO-PC | — | M42 cobalt / 29 pc | B00B0326OE | Industrial M42 value |
| Milwaukee 48-89-2331 | — | RED HELIX cobalt / 15 pc | B017POPUTE | Compact Milwaukee set |
| Viking/Norseman 69280 | — | M42 cobalt / 115 pc | B01CHJEVSI | Large professional index |
| Chicago-Latrobe 57850 | — | Cobalt / 29 pc | B000LDIR5Q | Premium industrial set |
1. Bosch CO14B — Best Compact M42 Cobalt Set
Bosch identifies the CO14B as a 14-piece M42 cobalt set for hard materials including stainless steel. The set uses 135° split-point geometry and a three-flat shank on larger sizes.
- Best for: Best Compact M42 Cobalt Set where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: Bosch CO14B fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • M42 cobalt construction • Compact 14-piece set • 135° split point • Manufacturer-documented stainless use | • Less size coverage than 21/29-piece sets |
Bosch specifications | Amazon — Bosch CO14B (ASIN B07Q9HNTBH)
2. Bosch CO21B — Best Larger Bosch M42 Set
The CO21B expands Bosch’s M42 cobalt line to 21 pieces and is intended for hard materials including stainless steel, cast iron, and titanium.
- Best for: Best Larger Bosch M42 Set where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: Bosch CO21B fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • M42 cobalt • 21-piece coverage • 135° split point • Three-flat shank on larger sizes | • Still not a complete 1/64-increment 29-piece index |
Bosch specifications | Amazon — Bosch CO21B (ASIN B07Q64LTFB)
3. DEWALT DWA1240 — Best Mainstream 14-Piece DEWALT Set
DEWALT’s DWA1240 uses cobalt alloy steel and PILOT POINT geometry and is designed for stainless steel and other hard metals.
- Best for: Best Mainstream 14-Piece DEWALT Set where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: DEWALT DWA1240 fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • 14-piece compact kit • Cobalt alloy steel • PILOT POINT starting control • Explicit stainless-steel application | • Smaller assortment than a full index |
DEWALT specifications | Amazon — DWA1240 (ASIN B015J5HU4Y)
4. DEWALT DWA1269 — Best DEWALT 29-Piece Fractional Index
The DWA1269 is a 29-piece cobalt drill-bit set covering a full fractional range and was built for hard metals including stainless steel. DEWALT now marks this model discontinued, so availability can vary, but the exact Amazon listing is still identifiable by ASIN.
- Best for: Best DEWALT 29-Piece Fractional Index where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: DEWALT DWA1269 fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • 29-piece fractional coverage • Cobalt construction • 135° point geometry • Designed for stainless steel | • Discontinued by DEWALT • Availability may fluctuate |
DEWALT archived specifications | Amazon — DWA1269 (ASIN B015J5HVAC)
5. IRWIN 3018002 — Best Traditional 29-Piece M35 Set
The 3018002 is a 29-piece M35 cobalt set spanning 1/16 through 1/2 in. in 1/64 in. increments. It is a classic shop index for repeated metal fabrication.
- Best for: Best Traditional 29-Piece M35 Set where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: IRWIN 3018002 fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • M35 5% cobalt • 29-piece full fractional index • 135° split point • Metal storage case | • Large set for occasional users |
Amazon — IRWIN 3018002 (ASIN B000BO9JMK)
6. Milwaukee 48-89-2332 — Best Milwaukee 29-Piece RED HELIX Set
The 48-89-2332 is a 29-piece cobalt RED HELIX set. Milwaukee’s RED HELIX line is designed around hard-metal drilling, rapid chip removal, and reduced heat buildup.
- Best for: Best Milwaukee 29-Piece RED HELIX Set where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: Milwaukee 48-89-2332 fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • 29-piece set • Cobalt construction • RED HELIX flute design • Hard-metal application focus | • Large kit if only a few diameters are needed |
Amazon — Milwaukee 48-89-2332 (ASIN B073R8T8QH)
7. Drill America D/A29J-CO-PC — Best M42 Industrial Value
The Drill America D/A29J-CO-PC is a 29-piece M42 cobalt jobber set from 1/16 through 1/2 in. by 1/64 increments. It uses 135° split-point geometry and a gold-oxide finish.
- Best for: Best M42 Industrial Value where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: Drill America D/A29J-CO-PC fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • M42 cobalt • 29-piece full fractional coverage • 135° split point • Industrial-style round case | • Round case is less compact than smaller kits |
Amazon — D/A29J-CO-PC (ASIN B00B0326OE)
8. Milwaukee 48-89-2331 — Best Compact Milwaukee RED HELIX Set
The 48-89-2331 is a 15-piece cobalt RED HELIX kit with 135° split-point geometry and variable-helix chip evacuation. Milwaukee now lists this exact model as no longer available from the manufacturer, so check the Amazon listing carefully before buying.
- Best for: Best Compact Milwaukee RED HELIX Set where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: Milwaukee 48-89-2331 fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • Compact 15-piece set • Cobalt construction • 135° split point • RED HELIX chip-removal design | • Discontinued by Milwaukee • Availability can vary |
Milwaukee archived specifications | Amazon — Milwaukee 48-89-2331 (ASIN B017POPUTE)
9. Viking/Norseman 69280 — Best Large M42 Cobalt Index
Norseman’s 69280 D-115 is a 115-piece M42 cobalt NAS 907J set covering fractional, letter, and numbered sizes. It is far more complete than most DIY users need, but it suits professional shops that want one large indexed set.
- Best for: Best Large M42 Cobalt Index where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: Viking/Norseman 69280 fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • M42 cobalt • 115-piece coverage • Fractional + letter + number sizes • Professional shop format | • Expensive • Overkill for occasional drilling |
Amazon — Viking/Norseman 69280 (ASIN B01CHJEVSI)
10. Chicago-Latrobe 57850 — Best Premium USA-Made 29-Piece Set
The Chicago-Latrobe 57850 is a 29-piece cobalt jobber-length set from 1/16 through 1/2 in. by 1/64 increments. It uses 135° split points and a gold-oxide/straw finish and is aimed at demanding hard-material drilling.
- Best for: Best Premium USA-Made 29-Piece Set where cobalt grade, point geometry, chip evacuation, and size coverage match the fabrication work.
- Why we picked it: Chicago-Latrobe 57850 fills a distinct stainless workflow based on alloy grade, point design, set coverage, case format, and whether it suits maintenance or repeated fabrication.
- Key strengths: heat-resistant cobalt construction, controlled starting geometry, useful fractional coverage, and a design that supports chip-making rather than surface rubbing.
- Important limitations: even premium cobalt bits can fail quickly if stainless work-hardens from rubbing, excessive RPM, weak feed, poor lubrication, or unstable workholding.
- What to check before buying: M35 vs M42 alloy, point geometry, diameter range, shank/chuck fit, replacement-bit availability, stainless grade, drill speed/feed, lubricant, and drill-press vs hand-drill rigidity.
- Who should buy it: fabricators and maintenance users drilling stainless often enough to benefit from cobalt heat resistance and controlled point geometry.
- Who should skip it: users whose main work is masonry, wood, tile, step-drilling thin sheet, or hardened material better served by another bit type/process.
| ✅ Pros | ❌ Cons |
|---|---|
| • Cobalt steel • 29-piece full fractional index • 135° split point • Industrial metal index case | • Premium price • Heavy-duty shop-oriented set |
Amazon — Chicago-Latrobe 57850 (ASIN B000LDIR5Q)
How to Avoid Work Hardening
The bit should produce chips instead of polishing the surface. Use a sharp bit, rigid workholding, appropriate cutting speed, and enough controlled feed for the edge to cut. If the bit squeals or rubs without making chips, stop and correct the setup.
Speed: Do Not Use One Universal RPM
Correct RPM depends on stainless grade, drill diameter, bit material, machine rigidity, and lubrication. Use the bit manufacturer’s recommendations or a machining chart for the exact diameter and alloy.
Lubrication and Chip Control
Use a suitable cutting fluid when recommended. Lubrication can reduce heat and wear, but it cannot compensate for a dull edge or inadequate feed. Clear chips safely.
Hand Drill vs. Drill Press
A hand drill can work for moderate holes with secure clamping. A drill press provides better alignment, rigidity, and feed control for repeated or larger holes.
Cobalt vs. Titanium-Coated HSS
Cobalt HSS contains cobalt in the tool alloy. Titanium-nitride-style products are coated. A coating label by itself does not make general-purpose HSS equivalent to a cobalt bit for repeated stainless drilling.
Manufacturer References
- Bosch Tools, DEWALT, and Milwaukee Tool — cobalt drill-bit alloy, point geometry, set contents, and hard-metal application specifications.
- IRWIN, Drill America, and Norseman — cobalt jobber-set and industrial index specifications.
FAQ
What bit material is best for stainless steel?
Cobalt HSS is a practical common choice for repeated stainless work because it retains hardness at elevated temperature better than ordinary HSS.
Should I drill stainless slowly?
Usually at lower surface speeds than softer metals, but exact RPM depends on diameter, bit material, and stainless grade.
Why does the bit only polish the surface?
Rubbing, a dull edge, or incorrect speed/feed can generate heat and work-harden the spot. Stop and correct the setup.
Who Should Buy Which Drill-Bit Set?
- Compact maintenance kit: Bosch CO14B or DEWALT DWA1240.
- More M42 sizes: Bosch CO21B.
- Full 29-piece fabrication index: IRWIN 3018002, Drill America D/A29J-CO-PC, DEWALT DWA1269, or Chicago-Latrobe 57850.
- Milwaukee consumable ecosystem: 48-89-2332/2331.
- Large professional index: Viking/Norseman 69280.
Included Contents, Replacement Bits, and Ownership Cost
Set count matters less than useful diameter coverage. Verify the exact fractional/metric range, storage index, and whether worn common sizes can be replaced individually. A premium 29-piece index can cost less long term than replacing several small sets if fabrication work routinely uses many diameters.
Who Should Skip These Sets?
Skip general cobalt twist-drill sets when the work is primarily sheet-metal step holes, masonry, wood, glass/tile, or very hard material requiring carbide/machine-tool processes. Use the tooling designed for the actual material and hole geometry.
Warranty, Value, and Availability
Drill bits are consumables, so manufacturer warranty policies may not cover normal edge wear. Compare current availability, replacement-bit access, alloy grade, usable sizes, and case quality rather than relying on temporary retailer ratings or discounts.
Alternatives and Related Tool Engineers Guides
For heat-treated material rather than stainless, use Tool Engineers’ hardened-steel drill-bit guide. For general metal drilling, use the broader metal guide so stainless-specific work-hardening advice does not distort the product choice.
Related Tool Engineers Guides
For technique, see How to Drill Stainless Steel. For material selection, see Cobalt vs Titanium Drill Bit and What Are Cobalt Drill Bits Used For?.
Final Verdict
The Bosch CO14B is the best compact documented M42 cobalt set in this roundup. For a full fractional index, choose among the DEWALT DWA1269, IRWIN 3018002, Drill America D/A29J-CO-PC, or Chicago-Latrobe 57850 based on budget and shop requirements.
