Drilling clean, accurate holes starts with the right bit, and stainless steel drill bits handle the toughest materials in your shop. Whether you mount shelving, build furniture, or fabricate metal brackets, the wrong bit walks across the workpiece, burns out fast, or leaves a ragged hole. This roundup covers nine solid options across twist sets, step bits, cobalt jobs, and size gauges, with a focus on real-world use rather than spec-sheet theatre. You’ll find picks for weekend DIYers, serious fabricators, and anyone tired of dull bits after a few projects.
The Lineup, Simplified
AULCTR 6PCS 3-8mm Titanium Coated HSS Drill Bit Set
AULCTR 8PCS 3-10mm Titanium Coated HSS Drill Bit Set
AULCTR 12PCS 3-8mm Titanium Coated HSS Drill Bit Set
AULCTR 18PCS 3-8mm Titanium Coated HSS Drill Bit Set
Greenlee GSB12 1-3/8″ Step Bit (#12) Metal Cutter
ViewReal Stainless Steel Drill Size Gauge 2-Pack
ViewReal 2 Pieces Drill Bit Size Gauge 29 Holes
IRWIN 3016011 11/64″ Cobalt Alloy Steel Drill Bit
Century Drill & Tool 11616 Letter Gauge Drill Bit, P
The Details Behind The Selections
Six bits covering the most common 3 to 8mm range make this AULCTR set a sensible starting point for someone who drills occasionally rather than daily. The titanium coating on high-speed steel reduces friction and helps the bit pull through wood, plastic, and thin aluminum with less walking at the start. Side-cutting serrations mean you can shape or open up a hole after the initial pilot, which saves a trip to the bits drawer when a fastener needs just a little more clearance.
For light home projects, picture hanging, or assembling flat-pack furniture, this set is honestly enough. If your projects lean toward thick steel plate or repeated heavy use, you’ll wear through titanium coating faster than you’d like, and a cobalt bit becomes the smarter choice.
Strengths Worth Knowing
- Titanium coating cuts friction, so bits stay cooler during longer drilling sessions
- Side-cutting serrations let you enlarge holes without swapping bits
- 3-8mm range covers most household pilot holes and small fasteners
- Lightweight kit fits a single drawer or a small tool roll
Trade Offs
- Coating tends to wear at the cutting edge after heavy metal use
- No storage case included, so bits rattle loose in a toolbox
- Only six sizes means gaps if you need anything below 3mm or above 8mm
Feature Snapshot
Made For
Occasional DIYers and renters handling furniture assembly, shelving, and small home repair jobs.
Consider Something Else When
Frequent metalworkers should reach for the IRWIN 3016011 cobalt bit, which handles harder materials far longer.
Stepping up to 3-10mm gives you clearance for thicker wall plugs, larger anchor bolts, and the kind of holes you actually need for mounting heavy shelves or TV brackets. The same titanium-over-HSS construction keeps the bit cooler than bare steel, and the serrated side edges handle the occasional oversize correction without a bit change. Garage tinkerers building workbenches or repairing outdoor fixtures will appreciate the wider top end.
Compared to the 6-piece set, the extra 9 and 10mm sizes open up most masonry anchor applications, which is the main reason to choose this version. Heavy fabrication work still calls for cobalt, but for wood-and-metal weekend builds, this range hits the sweet spot.
Well-Handled Touches
- Wider 3-10mm span covers anchor and bolt clearance holes
- Titanium coating helps the bit glide through aluminum and sheet metal
- Side-cutting teeth trim holes precisely when a pilot is slightly off
Honest Caveats
- Coating wears faster than solid carbide on stainless steel
- Step between sizes is uneven, so some gaps feel larger than others
Right Fit For
Home garage users mounting heavy fixtures, building storage, and handling medium-duty repair work.
Where Another Pick Suits Better
Workshop crews who wear through bits quickly should look at the AULCTR 18PCS set for more spares in common sizes.
Twelve bits across the 3-8mm range sounds like overlap until you realize it includes both metric and near-metric increments, which is genuinely useful when the project calls for a specific clearance. Compared to the 6-piece AULCTR set, you get duplicate coverage of the most common sizes, so when one dulls, you don’t stop work waiting for a replacement. The titanium-over-HSS build handles wood, plastic, and soft metal without complaint, and the serrated edges still trim holes when needed.
Hobbyists who build models, repair appliances, or do light fabrication get solid value here. The honest read is that twelve bits in this range will outlast most casual projects, and the redundancy pays off when you accidentally snap a smaller bit.
What It Does Well
- Twelve bits cover the 3-8mm range with overlapping sizes
- Titanium coating extends working life in wood and soft metal
- Side-cutting edges trim holes for snug fastener fit
- Spare bits reduce downtime when one dulls mid-project
Worth Noting
- Size increments don’t always match standard fastener charts
- No case means bits can mix together and dull each other in storage
Best Suited To
Hobby builders, model makers, and tinkerers who want redundancy in the most-used sizes.
Skip It When
Plumbers and electricians enlarging existing holes should pick the Greenlee GSB12 step bit instead.
Eighteen bits sound like overkill until you share a shop with other people, lend bits out, or simply lose the small ones in shavings. The same titanium-coated HSS recipe and side-cutting teeth from the smaller AULCTR sets carry over, which means consistent performance across the family. For community workshops, classroom settings, or family garages where multiple users reach for the same drawer, the redundancy is the main selling point.
Single-user hobbyists may find this much overlap unnecessary, and a smaller set would suit them better. The trade-off is bulk: eighteen loose bits take up more room than the 6-piece version, and they really need a dedicated case to stay organized.
Benefits That Matter
- Eighteen bits provide real redundancy for shared shops
- Titanium coating holds up well in wood and aluminum
- Side-cutting edges handle minor hole corrections
- Same proven design as the smaller AULCTR sets
Points To Note
- Bits ship loose, so a storage case is a worthwhile add-on
- More bits than most solo users will realistically wear through
Key Specs
Who Will Love This
Shared workshops, classrooms, and family garages where bits get borrowed, lost, or worn quickly.
Look Elsewhere When
Solo hobbyists should save space with the AULCTR 12PCS set, which covers the same range with less overlap.
Step bits earn their place when you need to drill multiple hole sizes with one tool, especially for conduit, plumbing boxes, and panel work. The Greenlee GSB12 steps up to 1-3/8 inches, which covers most standard electrical boxes and large plumbing penetrations. A split-step tip design helps the bit start without wandering on curved or slick metal, and the stepped profile means you can ream a small pilot out to a much larger opening without changing bits.
This is a specialist tool rather than a daily driver. Compared to twist sets, a step bit is the right call when you routinely enlarge existing holes or work with thin-gauge metal that demands clean, round openings.
Strong Points
- Steps up to 1-3/8 inches for large conduit and box openings
- Split-step tip starts accurately on slick or curved metal
- One bit replaces several fixed-size bits for hole enlargement
- Fits standard 1/2-inch drill chucks
Softer Spots
- Single-purpose tool, not a replacement for a full twist set
- Thick steel requires slow feed and cutting fluid for clean results
Quick Facts
Perfect Match For
Electricians, plumbers, and HVAC installers who regularly cut clean holes in metal panels and enclosures.
A Better Fit Elsewhere
Furniture builders and general DIYers get more daily use from the AULCTR 8PCS twist set.
A size gauge sounds unglamorous until you spend ten minutes squinting at a bit trying to figure out whether it’s a 7/32 or a 1/4. The ViewReal gauge covers fractional sizes from 1/16 to 1/2 inch plus the matching metric range, marked clearly on a stainless steel plate. The 2-pack gives you a backup or a second station in a busy shop, and stainless construction shrugs off the rust that plagues cheaper steel gauges in damp garages.
It’s not a drill bit itself, but it pairs with everything else in this roundup. Anyone mixing metric and imperial bits will reach for this more often than expected.
Everyday Wins
- 29 holes cover both fractional and metric bit sizes
- Stainless steel resists rust in humid shop environments
- Two gauges mean one for the bench and one for the toolbox
- Engraved markings stay legible longer than printed labels
Points To Keep In Mind
- Doesn’t gauge bits below 1/16 inch, common in precision work
- Sharp bit edges can scratch the gauge surface over time
Who Should Grab It
Shops mixing metric and imperial bits who need fast, accurate size identification.
Reach For A Different Pick When
Anyone needing letter-gauge sizing should consider the Century Drill & Tool 11616 P bit instead.
Functionally similar to the other ViewReal gauge, this 2-piece set ships in a single black finish that hides scuffs better than polished steel. The 29-hole layout covers the same fractional and metric range from 1/16 to 1/2 inch, and the stainless body keeps its shape in a busy drawer. Multiple gauges in one pack is genuinely useful when your shop has a couple of workstations and you don’t want to walk across the room just to size a bit.
Compared to the silver and black ViewReal 2-pack, this version trades color variety for a uniform finish. The honest read is that picking between the two comes down to aesthetic preference and current stock, since the specs and function are essentially identical.
A Favorable Mix
- Two gauges support multi-station workshops
- Stainless steel build handles humid or outdoor storage
- Black finish hides scratches and wear over time
- Engraved fractional and metric markings
Things To Weigh Up
- Identical to the other ViewReal gauge aside from color
Feature Card
Whose Shelf It Belongs On
Multi-user shops and busy hobbyists who want a gauge at every bench.
Another Choice May Suit
Solo workers with a single bench get by fine with the ViewReal silver-and-black 2-pack or even a single gauge.
Cobalt bits earn their reputation in tough metal, and the IRWIN 3016011 at 11/64 inch is a workhorse for stainless and hardened steel. A 135-degree split point (a tip geometry with a shorter, sharper angle that starts cutting on contact without a pilot dimple) bites into the surface without skating, which matters when you’re centering on a curved or already-hardened workpiece. Single bits like this are typically bought to fill one specific gap in a set, so think of it as a specialty purchase rather than a starter option.
For occasional wood or plastic work, this is overkill. Where it shines is in the maintenance and repair work the manufacturer calls out, where drilling tough alloys without softening the cutting edge is the whole job.
Points In Its Favor
- Cobalt alloy holds hardness at high drilling temperatures
- 135-degree split point improves starting accuracy on hard metal
- Ideal for stainless steel, cast iron, and tough alloys
Practical Considerations
- Single size means buying multiples for a full set
- More brittle than HSS if dropped or twisted at an angle
Product Snapshot
Built With In Mind
Maintenance crews, machinists, and metalworkers tackling stainless or hardened steel on a regular basis.
Swap It Out When
General home repairs don’t need cobalt strength, so the AULCTR 6PCS set is a more economical everyday choice.
Letter gauge drill bits (sized A through Z instead of by fractions or millimeters) cover size ranges that don’t line up neatly with standard inch increments, and the P size at 0.323 inch is a common pick for tapping and precision reaming. The Century Drill & Tool bit uses M2 high-speed steel with a 135-degree split point, ground from solid billet for consistent geometry. That matters when the hole has to match a specific fastener or machined tolerance, not just “close enough.”
This is firmly a specialty pick for machinists, gunsmiths, and serious fabricators. Most home DIYers won’t need a letter-gauge bit at all, but for those who do, the precision and material quality justify the single-bit purchase.
Where It Helps
- M2 high-speed steel holds up under repeated metal drilling
- 135-degree split point improves starting accuracy on hard surfaces
- Letter P (0.323 inch) suits specific tap and reaming sizes
- Ground from billet for consistent geometry
Minor Gripes
- Single-size purchase, so it doesn’t replace a general bit set
- Specialty sizing confuses shoppers who don’t know letter-gauge conventions
Perfect Match For
Machinists, gunsmiths, and fabricators who need letter-gauge precision for tapping or reaming operations.
Not Your Match When
Most homeowners and DIYers get by with the AULCTR 6PCS set and a ViewReal gauge for general sizing.
What To Weigh Before Choosing Stainless Steel Drill Bits
Bit Material and Coating
High-speed steel (HSS) with titanium coating suits general-purpose drilling in wood, plastic, and soft metal, with reduced friction helping bits stay cool. Cobalt alloy is the upgrade for stainless steel, cast iron, and other tough alloys, since it holds hardness at higher temperatures. If your projects lean toward mild steel and aluminum, titanium-coated HSS delivers good value. For maintenance work on harder metals, the upgrade to cobalt pays for itself in longer life and fewer snapped bits.
Size Coverage and Step Increments
Drill bit sets vary in how evenly they cover the size range. A 6-piece set in 1mm steps leaves gaps, while a 12-piece set with overlapping sizes gives you redundancy for the most common diameters. Match the size spread to your typical fasteners and pilot hole needs, and consider whether fractional or metric sizing matters more for your work.
Specialty Bits for Specific Jobs
Step bits, letter-gauge bits, and size gauges each solve narrow problems. Step bits enlarge existing holes in metal panels, letter-gauge bits hit specific tap and reaming sizes, and gauges solve the “what size is this bit” question that wastes time on every project. Buying the specialty tool only when you actually need it saves money and drawer space.
Storage and Longevity
Bits stored loose in a drawer dull each other through contact and make it harder to find the size you need. A case or dedicated organizer protects the cutting edges and speeds up bit selection. For cobalt and specialty bits especially, proper storage prevents the chips and cracks that come from bits rattling around with other tools.
Key Considerations Across These Picks
Where Shoppers Go Wrong
Buying a large bit set because it seems like better value often backfires when half the sizes never get used, and the ones you do use go dull. Match the set to your actual project range, and add specialty bits only as specific needs come up. Skipping a size gauge is another common miss, since it leads to guessing on fastener fit and ruined holes.
Where The Extra Money Goes
Cobalt bits cost more because the alloy holds hardness at drilling temperatures that would soften standard HSS, and the manufacturing process yields more consistent geometry. For occasional drilling in soft materials, the upgrade is hard to justify, but for anyone regularly working in stainless or hardened steel, the longer life and cleaner holes pay back the higher cost quickly. Specialty bits like the Greenlee step bit also earn their price by replacing several fixed-size tools with one adjustable cutter.
Frequently Asked Questions
What is the difference between HSS and cobalt drill bits?
HSS (high-speed steel) bits are a cost-effective general-purpose option for wood, plastic, and soft metals, while cobalt bits are an alloy designed to maintain hardness at higher temperatures, making them better for stainless steel, cast iron, and other tough materials. Cobalt bits also tend to be more brittle if mishandled.
Can titanium-coated drill bits be sharpened?
Yes, but the coating wears at the cutting edge first, so once sharpening exposes the underlying HSS, the bit loses its low-friction advantage. Touch-up sharpening with a dedicated bit sharpener is common, and you can expect a few sharpenings before the coating is gone entirely on frequently used bits.
How do I know which drill bit size I need?
A drill bit gauge like the ViewReal 2-pack lets you match bits to fractional or metric sizes in seconds, with clearly marked holes from 1/16 to 1/2 inch. For specific fasteners, check the manufacturer’s pilot hole recommendation, since oversizing leads to loose fits and undersizing risks splitting the workpiece.
Are step bits worth it for home use?
Step bits earn their keep when you regularly enlarge existing holes or drill clean, round openings in thin metal for electrical boxes and conduit. For occasional wood and plastic work, a standard twist set handles most tasks. Plumbers, electricians, and HVAC installers get the most value from a step bit.
How should I store drill bits to keep them sharp?
A dedicated case or organizer prevents bits from rattling against each other and dulling the cutting edges, which is especially important for brittle cobalt bits. Magnetic strips, labeled drawers, or the original case all work, and keeping bits dry avoids the rust that plagues cheaper steel in humid garages.
