Drilling into stainless steel is a battle against hardness, heat, and a wandering bit that skates across the surface instead of biting in. The wrong drill bit either dulls in seconds, snaps under pressure, or leaves a ragged, oversized hole that ruins the work piece. This category demands bits engineered with specific cobalt content, a precise point geometry, and a rigid shank design to maintain concentricity under the high torque required to penetrate work-hardening alloys.
I’m Mo Maruf — the founder and writer behind The Tools Trunk. I analyze cobalt alloy percentages, split-point angles, and flute geometries across dozens of twist drill sets to separate the bits that actually cut stainless from those that just spin and squeal.
After evaluating material composition, tip design, and real-world drilling performance, this guide ranks the most reliable sets to buy right now for the drill for stainless steel that will handle hardened alloys without constant replacement.
How To Choose The Best Drill For Stainless Steel
Stainless steel work-hardens as you cut, meaning a dull bit or incorrect feed rate will glaze the surface and make subsequent drilling exponentially harder. The right drill bit selection comes down to three interdependent factors: the steel alloy of the bit itself, the point geometry that initiates the cut, and the number of flutes that clear the hot chips away from the cutting zone.
Cobalt Content and Steel Grade
Standard high-speed steel (HSS) bits lack the red hardness to withstand the frictional heat generated when drilling stainless. Look for M35 cobalt steel, which contains 5% cobalt, or M42 with 8% cobalt. The cobalt addition allows the cutting edge to retain hardness at elevated temperatures, preventing the rapid blunting that occurs when ordinary HSS bits encounter the chromium carbide particles in stainless steel.
Point Geometry: The 135-Degree Split Point
A conventional 118-degree point tends to walk across the convex surface of stainless steel rather than engaging cleanly. The 135-degree split point creates a self-centering chisel edge that reduces the required axial thrust and produces a more accurate hole start. The split ground into the point also generates two additional cutting edges that shear the work-hardened layer more efficiently.
Flute Count and Chip Evacuation
Stainless steel produces stringy, tough chips that can clog standard 2-flute drill flutes and cause heat buildup or bit breakage. Some specialized bits use a 3-flute design to create smaller, more manageable chips and provide more surface area for heat dissipation. For deep holes, a 2-flute with a polished flute surface and adequate helix angle is often more practical because it clears chips upward without packing them into the flutes.
Quick Comparison
On smaller screens, swipe sideways to see the full table.
| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| COMOWARE 21-Piece Set | Mid-Range Set | General stainless drilling, DIY workshops | M35 Cobalt, 1/16″-3/8″ range | Amazon |
| EASTPACE 29-Piece Set | Premium Set | Heavy-duty fabrication, full-size coverage | Black & Gold Oxide, up to 1/2″ | Amazon |
| Bestwork 3-Flute Set | Mid-Range Set | Higher hole roundness, electricians | 3-Flute design, 1/16″-1/2″ | Amazon |
| VALYRIANTOOL Silver & Deming | Single Bit | Large holes over 1/2″ in thick steel | 1-3/8″ diameter, reduced shank | Amazon |
| VEVOR 29-Piece Set | Mid-Range Set | Versatile home shop, budget-friendly | M35 Cobalt, includes up to 1/2″ | Amazon |
In‑Depth Reviews
1. COMOWARE 21-Piece M35 Cobalt Drill Bit Set
The COMOWARE set hits the sweet spot of spec and value with 21 pieces covering 1/16-inch to 3/8-inch, all forged from M35 high-speed steel with 5% cobalt. The 135-degree split point is properly ground, providing immediate bite on stainless without skating, and the twisted shank design directs chips upward during deep cuts. Users report drilling through stainless fittings and cast iron pipe without the bits losing edge retention across multiple jobs.
What separates this set from others at a similar price tier is the consistency of the cutting edges. Some budget cobalt sets suffer from uneven grinding, leaving certain bits significantly less sharp than others; COMOWARE maintains uniform geometry across all 21 pieces. The included indexed metal storage case keeps the bits organized and protected, though the case itself is a simple box without individual snap-in slots for each size.
For the DIY metalworker or light fabrication shop that needs a reliable daily driver for stainless steel, this set delivers the hardness and tip accuracy to handle work-hardening alloys without burning through the budget. The bits perform best with a steady feed rate and cutting oil, and they maintain their edge noticeably longer than off-the-shelf HSS sets.
What works
- Consistent M35 hardness across all sizes
- Self-centering split point reduces walk
- Storage case keeps bits organized
What doesn’t
- Case lacks individual snap-in slots
- Some users reported occasional less-sharp bits
2. EASTPACE 29-Piece Black and Gold Oxide Cobalt Set
The EASTPACE set steps up the coverage with 29 pieces spanning 1/16-inch all the way to 1/2-inch, giving you the larger diameters often needed for heavy stainless plate and structural work. The dual black and gold oxide coating increases surface lubricity, reducing friction during the cut and helping prevent the galling that plagues bare steel bits in stainless. The 135-degree split point is fully ground, ensuring each bit starts true without walk.
Users report these bits chewing through wood, tile, and heavy-duty metal without losing sharpness, and the inclusion of metric-friendly sizes like 25/64-inch and 29/64-inch fills gaps that smaller sets leave open. The round metal storage case is sturdy but has a minor design flaw: the bits can shift and rattle inside unless the case is kept upright, so it is not ideal for tossing into a crowded tool bag.
For the professional fabricator or serious hobbyist who needs a broad size range and the coating benefits for repetitive stainless drilling, this set represents a solid investment in longevity. The oxide layers provide genuine heat resistance during extended use, and the full set reduces the need to buy individual bits for odd-size holes.
What works
- Wide size range up to 1/2-inch
- Oxide coating reduces galling on stainless
- Bits stay sharp through repeated use
What doesn’t
- Case allows bits to shift when not upright
- Case construction feels slightly crude
3. Bestwork 21-Piece 3-Flute Cobalt Drill Bit Set
The Bestwork set introduces a 3-flute geometry that fundamentally changes how the bit interacts with stainless steel. Instead of two cutting edges, the third flute provides an additional shearing point, producing a hole with higher roundness and smoother sidewalls compared to traditional 2-flute designs. The three flutes also create more pathways for chip evacuation and heat dissipation, critical when drilling deep holes in work-hardening stainless.
Notably, the set uses a mix of 2-flute and 3-flute bits depending on size: the larger diameters (1/4-inch through 1/2-inch) are 3-flute, while the smaller sizes (below 1/4-inch) are standard 2-flute. This makes practical sense because small bits benefit from the chip clearance of two flutes, while larger bits leverage the roundness advantage of three. The 3-flat shank design prevents chuck slip under the higher torque required by the 3-flute cutting action.
Professional electricians drilling stainless steel boxes report excellent results with this set, particularly praising the 1/2-inch and 3/16-inch sizes for conduit and box work. The tradeoff is that the 3-flute design can require slightly more feed pressure because it removes material more aggressively per revolution, so a rigid drill press or strong handheld drill is recommended.
What works
- Higher hole roundness with 3-flute design
- 3-flat shank eliminates chuck slip
- Excellent chip evacuation and heat dissipation
What doesn’t
- Requires more feed pressure than 2-flute bits
- Small sizes are still 2-flute only
4. VALYRIANTOOL 1-3/8 Inch M35 Cobalt Silver & Deming Bit
When you need to push a 1-3/8-inch hole through thick stainless steel plate, standard jobber-length bits simply cannot handle the torque. The VALYRIANTOOL Silver & Deming bit solves this with a reduced shank design: the cutting diameter is 1-3/8 inches, but the shank is machined down to 1/2-inch to fit a standard drill chuck. The M35 cobalt construction with gold oxide finish provides the heat resistance necessary to maintain the cutting edge during extended drilling cycles.
The 135-degree split point is ground cleanly and delivers accurate centering even on curved surfaces like crane boom pins or thick wall tubing. Users report drilling through 3/4-inch steel plate and heavy structural members without chipping or dulling, and the 3-flat shank keeps the bit firmly gripped in the chuck. The gold oxide treatment adds lubricity at the cutting interface, which is especially important when coolant cannot be applied continuously.
This is a single-purpose bit for specific large-hole applications — not a general-purpose set. It pairs best with a magnetic drill press or a corded 1/2-inch drill that can maintain low RPM under heavy load. For fabricators, millwrights, and heavy equipment repair, this bit fills a critical gap that no set can cover.
What works
- Reduced shank fits standard 1/2″ chucks
- Cobalt edge holds up in heavy steel
- 135° point centers accurately on curves
What doesn’t
- Single bit only, no multi-size set
- Requires low-RPM drill or press
5. VEVOR 29-Piece M35 Cobalt Drill Bit Set
VEVOR enters the stainless drilling market with a 29-piece M35 cobalt set that undercuts most competitors on cost while maintaining the essential specifications: 5% cobalt content, 135-degree split point, and sizes from 1/16-inch to 1/2-inch. The black oxide finish provides a modest lubricity benefit, though not as pronounced as the premium oxide coatings on higher-priced sets. The included storage case is well-made and keeps bits secure and accessible.
The tradeoff for the lower entry point is in the brittleness of the steel. Multiple users note that applying any sideward pressure will snap these bits, requiring dead-straight alignment with downward force only. This is a common characteristic of budget cobalt bits — the hardness that gives them cutting ability also makes them more prone to fracture under lateral stress. When used correctly with steady vertical pressure and cutting oil, they perform admirably through stainless, aluminum, and wood.
For the DIY homeowner or weekend fabricator who needs an affordable entry into cobalt bits for occasional stainless drilling, this set offers tremendous hardware per dollar. It is not the best choice for demanding production environments where bit breakage causes costly downtime, but for the home shop, the VEVOR set delivers capable performance at a fraction of the premium-tier price.
What works
- Low cost for M35 cobalt construction
- Full 29 sizes from 1/16″ to 1/2″
- Storage case is well-constructed
What doesn’t
- Brittle under side-load, snaps easily
- Black oxide finish is less durable than premium coatings
Hardware & Specs Guide
M35 vs M42 Cobalt Steel
M35 high-speed steel contains 5% cobalt, providing a good balance of toughness and heat resistance for general stainless drilling. M42 contains 8% cobalt, offering greater red hardness at the expense of some impact resistance. For most home and light industrial work, M35 is sufficient. M42 is preferred for production drilling where continuous high-speed cuts generate extreme heat.
135° Split Point Geometry
The 135-degree point angle is steeper than the standard 118-degree grind, creating a more acute cutting edge that reduces the force required to penetrate work-hardened surfaces. The split chisel point further improves centering by creating two additional cutting edges that shear the material at the center of the hole, eliminating the need to center-punch in many applications.
Flute Design and Helix Angle
Standard twist drills use a 2-flute design with a helix angle around 30 degrees. For stainless steel, a higher helix angle (35-40 degrees) improves chip evacuation by creating a steeper ramp for chips to climb. The 3-flute design, found on the Bestwork set, sacrifices some chip clearance for additional shearing edges and improved hole roundness.
Shank Configuration
Round shanks will slip in a drill chuck when the cutting torque exceeds the chuck’s grip, especially with large diameter bits. The 3-flat shank design provides three machined flats that give the chuck jaws positive mechanical engagement, preventing rotation under load. Reduced-shank bits (Silver & Deming style) allow large cutting diameters to fit standard 1/2-inch chucks.
FAQ
Can I use standard HSS drill bits on stainless steel?
Why does my drill bit keep walking on stainless steel?
What RPM should I use when drilling stainless steel with cobalt bits?
Does a 3-flute drill bit really work better than a 2-flute on stainless?
Is cutting oil really necessary for drilling stainless steel?
Final Thoughts: The Verdict
For most users, the drill for stainless steel winner is the COMOWARE 21-Piece M35 Cobalt Set because it delivers consistent 5% cobalt hardness and accurate 135-degree split points across a practical size range at a mid-range price. If you want the broader size coverage and oxide coating benefits for heavier use, grab the EASTPACE 29-Piece Set. And for large-diameter holes in thick stainless plate, nothing beats the VALYRIANTOOL 1-3/8″ Silver & Deming Bit.