Drilling a 16mm hole through steel often turns into a battle with chatter, wandering tips, and bits that dull after a dozen passes. A properly selected 16mm drill bit eliminates that friction—delivering clean, round holes with predictable torque and minimal heat buildup.
I’m Min — the co-founder and writer behind Gadgets Feed. I’ve spent countless hours analyzing cutting geometries, flute designs, and material compositions across dozens of 16mm options to isolate the bits that actually hold an edge in real workshop conditions.
Whether you’re reaming suspension components or boring through stainless sheet, finding the right tool starts here. This guide breaks down every technical factor that separates a precision tool from a frustration source, so you can confidently choose the best 16mm drill bit for your exact application.
How To Choose The Best 16mm Drill Bit
A 16mm bit is a relatively large diameter, demanding more from the drill motor and the bit material. Choosing poorly means excessive heat generation, binding, or snapping the bit mid-hole. Focus on material compatibility, shank style, and coating to match your workpiece.
Material Composition: HSS, Cobalt, or Carbide
Standard HSS bits work fine for wood and aluminum, but for stainless steel or high-strength alloys, Cobalt M35 or tungsten carbide tips are non-negotiable. Cobalt bits retain hardness at elevated temperatures, while carbide-tipped hole saws resist abrasion from masonry and hard metals.
Point Geometry: The 135-Degree Split Point Advantage
A 135-degree split point offers a self-centering action that prevents the bit from skating across a smooth surface—critical when drilling a 16mm hole without a center punch. The chisel edge is essentially eliminated, reducing the thrust required to initiate the cut.
Shank Design: Hex vs. Round with Safety Flats
At 16mm, torque load is substantial. A hex shank delivers positive drive in impact drivers and prevents spin-out in quick-change chucks. A round shank with three safety flats (like the 10mm shank found on many hole saws) provides superior grip in a standard three-jaw chuck, especially under heavy feed pressure.
Quick Comparison
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| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| GRIXLEN 5/8″ Tungsten Carbide Hole Saw | Hole Saw | Hard metal & stainless | Carbide tip, 25mm depth | Amazon |
| THINKWORK Metric Step Drill Bit Set | Step Bit | Multi-size precision | Cobalt M35 spiral flute, 6mm hex | Amazon |
| DECKRKAT 5/8″ Reamer Drill Bit | Reamer | Precision alignment & enlarging | 5 spiral flutes, 1/2″ shank | Amazon |
| Mgtgbao Dry Diamond Drill Bits Set | Diamond Core | Tile & masonry drilling | 16mm hex shank, wax cooling | Amazon |
| SALI Cobalt Drill Bit Set | Jobber Bit | High-volume metal work | M35 Cobalt, 135° split point | Amazon |
| Jerax Tools Step Drill Bit | Step Bit | Clean holes in sheet metal | M2 HSS, nitride finish, 12 sizes | Amazon |
| HIGHFIRE Hex Shank Drill Bits | Jobber Bit | DIY & general repair | 1/16” dia, HSS, TiN coated | Amazon |
In‑Depth Reviews
1. GRIXLEN 5/8″ Tungsten Carbide Hole Saw
This two-pack of 16mm hole saws uses a tungsten carbide cutting edge brazed onto a steel body, giving it the hardness to bite through stainless and iron plate without glazing. Users report cutting through 11-gauge steel cleanly at low RPM with lubricant, and the 3-flat 10mm shank prevents spin-out under heavy torque.
Each saw has a cutting depth of 25mm, enough for most sheet and plate work. The included M2 HSS pilot bit keeps the hole saw tracking true during initial contact—critical for avoiding oblong holes. Reviewers note that the carbide edge stays sharp far longer than standard fluted HSS bits when used on hard metals.
Some users found the saw a bit delicate for aggressive hand-drilling through thick steel, recommending a drill press for thick material. At moderate speeds with coolant, however, this set delivers clean, chatter-free holes that justify the premium material choice.
Why it’s great
- Carbide tip cuts hard materials (stainless, iron) without dulling
- Accurate 16mm diameter with minimal runout
- Two-pack provides backup for demanding jobs
Good to know
- Fragile in hand drilling without a drill press on thick steel
- Cutting depth limited to 25mm
2. THINKWORK Metric Step Drill Bit Set
This five-piece set covers metric sizes from 6mm through 16mm, with the 16mm step being the largest in the kit. Each bit is constructed from Cobalt M35 HSS and uses a spiral flute geometry that pulls chips upward instead of packing them into the hole—critical when stepping up from a pilot bore.
Users report drilling 55 holes through 0.265″ A36 steel without re-chucking, with final hole tolerances staying within thousandths of nominal. The 6mm hex shank locks securely in impact drivers, preventing the bit from twisting under the heavy load of a 16mm cut.
While these bits are excellent for light to medium duty, professional users note they aren’t designed for continuous production drilling in hardened steel. For the DIY shop, automotive work, or electrical panel modifications, this set delivers industrial-grade precision at a mid-range investment.
Why it’s great
- M35 cobalt spiral flute handles stainless and A36 steel
- Metric step sizing eliminates bit changes
- Laser-etched markings remain legible after repeated use
Good to know
- Not intended for hardened tool steel applications
- Hex shank works best with impact drivers, not standard chucks
3. DECKRKAT 5/8″ Reamer Drill Bit
Unlike standard twist bits, this dedicated reamer uses five spiral flutes to enlarge existing holes with sub-millimeter precision. Its tapered point guides smoothly into a predrilled bore, and the 1/2″ round shank with three safety flats ensures zero slip in a standard drill chuck. Designed for automotive ball joint holes, bridge steel alignment, and heli-coil preparation.
Reviewers successfully enlarged suspension knuckle holes and spark plug bores, noting that the bit maintains alignment even at the full 5/8″ diameter. The nickel finish reduces friction, and used with cutting oil, the flutes evacuate material efficiently without binding.
A small number of users encountered rapid dulling when attempting heavy reaming in thick steel. This tool is best applied as a finishing reamer for 1-2 thousandths of stock removal per pass, not as a roughing tool for hogging out large amounts of material.
Why it’s great
- Five-flute design delivers smooth, concentric reaming
- Tapered point centers naturally in pilot holes
- Safety flats prevent chuck slippage at high torque
Good to know
- Best for finishing passes, not heavy roughing
- Some users noted limited lifespan in thick steel
4. Mgtgbao Dry Diamond Drill Bits Set
This six-piece set of 16mm diamond core bits is engineered specifically for hard, brittle materials: porcelain tile, granite, marble, concrete, and masonry. Each bit embeds diamond grit at the cutting edge and integrates a wax lubricant that melts during drilling to cool the interface—enabling dry operation without cracking the tile.
One user drilled 100 holes in concrete steps using only a single bit, thanks to the wax cooling system. The 1/4″ hex shank fits common impact drivers and quick-change chucks, making it convenient for overhead work or tight spaces where a bulky drill press won’t reach.
These bits are not suitable for wood, plastic, or soft metals—the diamond matrix is designed for abrasive materials only. While they work dry, dipping the bit in water every 10-15 seconds extends the life significantly, especially on very hard stone like basalt.
Why it’s great
- Integrated wax cooling allows dry drilling on tile without cracking
- Six identical 16mm bits provide redundancy for large projects
- Diamond grit cuts granite and concrete with minimal effort
Good to know
- Not for wood or metal applications
- Water cooling extends life but is not required
5. SALI Cobalt Drill Bit Set
Each bit in this 10-pack is constructed from M35 cobalt steel, which incorporates additional cobalt content over standard M2 for superior red hardness. The 135-degree split point starts cleanly on curved or uneven surfaces without a center punch, and the parabolic flute geometry accelerates chip evacuation in deep holes.
One professional user drilled over 200 holes through 1/4″ steel on the first bit before noticing performance degradation. Another reported using these for metal roof outlines, getting 80 clean holes per bit in an impact driver before dulling. For high-volume metal work, this set delivers exceptional value in a jobber-length package.
A small number of users experienced shank fractures at the junction between the hex and the flute body, typically when applying excessive side load. Proper alignment and consistent feed pressure are important to protect the bit’s torsional integrity.
Why it’s great
- M35 cobalt composition withstands high temperatures from sustained drilling
- 135° split point eliminates walking on smooth steel
- Parabolic flutes clear chips rapidly in deep bores
Good to know
- Hex shank may break under aggressive side loading
- Not suitable for masonry or tile
6. Jerax Tools Step Drill Bit
This single step bit covers 12 hole sizes from 3/16″ to 7/8″, with the 5/8″ (16mm) step clearly highlighted for at-a-glance identification. The nitride surface treatment increases hardness compared to bare HSS, and the double-fluted design produces cleaner edges than straight-flute step bits on thin-gauge sheet metal.
Users report cutting through 12-gauge stainless steel without a pilot hole—a serious testament to its edge geometry—and consistently clean holes in aluminum and plastic enclosures. The precision-ground step transitions ensure gentle material swelling rather than tearing as the bit progresses through the stock.
The uncoated cutting edge is more prone to rust than titanium-nitride coated bits, so a light oil wipe after use is recommended. For light to moderate fabrication, electrical work, and DIY projects, this step bit packs impressive versatility into a single tool.
Why it’s great
- Cuts stainless steel without a pilot hole
- 12 marked sizes reduce the need for bit changes
- Nitride finish provides good wear resistance
Good to know
- Uncoated edges may corrode if not maintained
- Best for sheet metals under 3mm thickness
7. HIGHFIRE Hex Shank Drill Bits
This 12-pack of 1/16″ hex shank bits is built for general-purpose maintenance and repair work. Each bit uses a 135-degree split point for easy starting on metal surfaces, with a titanium nitride coating that extends edge life three times beyond uncoated HSS. The hex shank eliminates spin-out in quick-change impact drivers.
Users praised the value consistently—using them for laser-drilled slate coasters, general wood drilling, and light metal tasks. The tapered web design adds rigidity to the small diameter, reducing the risk of snapping on entry. For precision work at the 1.59mm scale, these bits hold up well against pricier alternatives.
The 1/16″ diameter is not the 16mm most readers need for larger hole jobs. This set is specifically included for users who also require very small pilot or precision holes. If your primary need remains 16mm bores, pair this with one of the larger bits from earlier in this guide.
Why it’s great
- TiN coating extends life compared to bare HSS bits
- Hex shank prevents slipping in impact drivers
- Excellent value for a 12-pack of precision small bits
Good to know
- 1/16″ diameter is far smaller than 16mm—not for standard hole drilling
- Best for pilot holes and fine metal work
FAQ
Can I use a 16mm step bit to drill through 1/4″ steel?
Why does my 16mm bit keep walking on a smooth surface?
How much coolant or lubricant should I use when drilling a 16mm hole in stainless steel?
Final Thoughts: The Verdict
For most users, the best 16mm drill bit winner is the GRIXLEN Tungsten Carbide Hole Saw because its carbide edge cuts hard metal like stainless steel without glazing, and the 2-pack provides backup for tough jobs. If you need a multi-size solution with cobalt durability, grab the THINKWORK Metric Step Bit Set. And for precision reaming tasks where hole diameter must be exact, nothing beats the DECKRKAT 5/8″ Reamer.