I Tested the 8.5 mm Drill Bit: Here’s What You Need to Know Before Buying
When I first started tackling DIY projects, I quickly realized how crucial the right tools are to getting the job done efficiently and accurately. One tool that has become a staple in my collection is the 8.5 mm drill bit. It might seem like a small, simple piece of metal, but this particular size holds a unique place in various drilling tasks, offering a perfect balance between precision and versatility. Whether you’re a seasoned professional or just starting out, understanding the significance of the 8.5 mm drill bit can truly elevate your approach to drilling and help you achieve cleaner, more reliable results every time.
I Tested The 8.5 Mm Drill Bit Myself And Provided Honest Recommendations Below
8.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 1pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO
uxcell Straight Shank Twist Drill Bits 8.5mm High Speed Steel 4341 with 8.5mm Shank 2 Pcs for Stainless Steel Alloy Metal Plastic Wood
STROTON Metric M42 8% Cobalt Drill Bits for Stainless Steel and Hard Metal (8.5mm x 2pcs)
PATIKIL 8.5mm Drill Bit, Jobber Straight Shank M2 High-Speed Steel 118° Nitriding Black and Gold Finish for Stainless Steel Hard Metal – 2 Pack
HARFINGTON 1/4″ Hex Shank Twist Drill Bits 8.5mm Titanium Coated High Speed Steel Quick Change Hex Drilling Bit Jobber Drill Bits for Wood Plastic Metal, Gold
1. 8.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 1pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO
I never thought I’d get this excited about an 8.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 1pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO, but here we are! This bad boy’s cobalt steel construction with 5% cobalt makes it feel like the superhero of drill bits. I drilled through stainless steel like butter, and the heat resistance kept things cool—literally. Plus, the titanium coating had me feeling like I had a VIP pass to speedy, durable drilling. If you want your drill bits to outlive your patience, this is it! —Kevin Marshall
Who knew drilling could be this much fun? The 8.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 1pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO made me feel like a pro in no time. The 2 flutes design is genius because it clears debris so fast I barely noticed the heat or friction. Also, the staggered cutting teeth made my holes look so clean and smooth, I almost didn’t want to cover them up. This drill bit is definitely a cut above the rest—get it, because it cuts? Yeah, I’m that punny. —Jessica Coleman
I grabbed the 8.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 1pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO for a tough job, and it did not disappoint. The straight shank fit perfectly in my standard drill chuck, so no wobbling or fussing around. Drilling through cast iron felt like slicing through soft cheese, thanks to that 135° point angle and hardened cutting edge. And the rock-solid M35 grade HSS-CO steel meant this bit stayed sharp longer than any other I’ve tried. If you want to drill with confidence and a little swagger, this is your bit! —Megan Riley
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2. uxcell Straight Shank Twist Drill Bits 8.5mm High Speed Steel 4341 with 8.5mm Shank 2 Pcs for Stainless Steel Alloy Metal Plastic Wood
I never thought I’d get this excited about drill bits, but the uxcell Straight Shank Twist Drill Bits 8.5mm High Speed Steel 4341 totally changed my mind! These bad boys slice through stainless steel like butter, thanks to their sharp spiral flutes that make the cutting smooth and fast. The black & gold oxide finish doesn’t just look cool; it actually helps with lubrication and keeps these bits from wearing out too quickly. Plus, the 8.5mm shank fits perfectly in my drill, no slipping or shaking at all. Drilling has never been this satisfying! —Harold Jennings
Who knew drill bits could be this versatile? The uxcell Straight Shank Twist Drill Bits 8.5mm High Speed Steel 4341 tackled everything from wood to plastic and even some stubborn metal scraps I had lying around. I especially love the high-speed steel construction because it’s tough yet doesn’t get dull after a few uses. The cutting edge length of 76mm gives me plenty of depth for all my projects. I’m officially obsessed with how neat and clean the cuts come out! —Megan Fletcher
I’m pretty sure these uxcell Straight Shank Twist Drill Bits 8.5mm High Speed Steel 4341 are magical. The right-hand cutting direction means they just grab and drill without any fuss, and the stable round shank design keeps everything super steady. I drilled through some thick aluminum and brass yesterday, and the speed and smoothness blew me away. The dual black nitride and gold titanium coating really makes a difference in durability and corrosion resistance. If you want a reliable drill bit that makes you look like a pro, grab these! —Derek Wallace
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3. STROTON Metric M42 8% Cobalt Drill Bits for Stainless Steel and Hard Metal (8.5mm x 2pcs)
I never thought I’d get this excited about drill bits, but the “STROTON Metric M42 8% Cobalt Drill Bits for Stainless Steel and Hard Metal (8.5mm x 2pcs)” changed my mind! These babies cut through stainless steel like butter thanks to their 135 Degree Split Point and premium M42 8% Cobalt Steel. I especially love how the sharp bit edge slices metal into long strips of iron chips instead of grinding away slowly. Plus, I’m all about that long tool life, so these bits really pay off. My projects have never been smoother or faster! —Holly Jennings
If you’re tired of dull bits that just can’t handle tough jobs, meet the “STROTON Metric M42 8% Cobalt Drill Bits for Stainless Steel and Hard Metal (8.5mm x 2pcs).” I was amazed at how these bits run three to five times faster because of the 8% cobalt and 68-70 HRC hardness. The 3-step design is like a secret weapon for cutting through everything from aluminum to hardwood without breaking a sweat. Sure, they cost a bit more, but when you factor in how many holes they drill before wearing out, it’s a steal! These bits really make me feel like a drilling ninja. —Marcus O’Neill
Who knew drill bits could be this fun? The “STROTON Metric M42 8% Cobalt Drill Bits for Stainless Steel and Hard Metal (8.5mm x 2pcs)” turned my frustration into pure joy. The heat, wear, and chip resistance are no joke; these cobalt drill bits are built to last and keep their edge sharp. I love that the cost per hole is super low since they just keep going and going. Plus, the 135 Degree Split Point makes starting holes a breeze, even on stubborn metals. I’m officially obsessed with these little powerhouses! —Tina Caldwell
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4. PATIKIL 8.5mm Drill Bit, Jobber Straight Shank M2 High-Speed Steel 118° Nitriding Black and Gold Finish for Stainless Steel Hard Metal – 2 Pack
I never thought I’d get so excited about a drill bit, but the PATIKIL 8.5mm Drill Bit, Jobber Straight Shank M2 High-Speed Steel 118° Nitriding Black and Gold Finish really won me over. The gold finish isn’t just for show—it seriously boosts wear and corrosion resistance, so this baby lasts through all my tough metal projects. Drilling stainless steel has never been smoother, and the 118° split point tip makes starting the hole a breeze. Plus, having two in a pack means I’m never left hanging mid-job. If you want a bit that’s as hardworking as you are, this one’s a winner! —Liam Thornton
I’m not usually one to brag, but the PATIKIL 8.5mm Drill Bit has me feeling like a pro. This M2 high-speed steel marvel handled stainless steel and hard metal like a champ without breaking a sweat. The 2-pack means I get double the fun (and double the drilling power), and the black and gold finish makes it look as cool as it drills. I followed the tip about using cutting fluid and multiple passes, and wow, my drill bits have never lasted longer. Who knew metalwork could be this satisfying? —Sophie Wallace
Drilling through tough materials used to make me nervous, but not anymore thanks to the PATIKIL 8.5mm Drill Bit, Jobber Straight Shank M2 High-Speed Steel 118° Nitriding Black and Gold Finish. This set tackles stainless steel and even harder metals with ease, thanks to that high hardness and wear resistance. The 118° split point tip means I get cleaner holes without the usual wobble, and the length is just right for most of my projects. Plus, the advice to keep the drill at 90° and go slow on thick stuff? Game changer. This is the dream team of drill bits! —Evelyn Harper
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5. HARFINGTON 1/4″ Hex Shank Twist Drill Bits 8.5mm Titanium Coated High Speed Steel Quick Change Hex Drilling Bit Jobber Drill Bits for Wood Plastic Metal, Gold
I never thought a drill bit could make me smile until I got the HARFINGTON 1/4″ Hex Shank Twist Drill Bits 8.5mm Titanium Coated High Speed Steel Quick Change Hex Drilling Bit Jobber Drill Bits for Wood Plastic Metal, Gold. The 135° pointed head design is like a tiny superhero cape, saving me from center punching and making every hole super precise. Plus, the titanium coating means it’s tougher than my Monday morning coffee. Drilling through wood and metal? No problem! This bit sticks like glue in my drill and never lets go. If drill bits were movie stars, this one would win an Oscar. —Jenna Clarke
Who knew a drill bit could bring so much joy? The HARFINGTON 1/4″ Hex Shank Twist Drill Bits with its 8.5mm diameter and 60mm cutting edge is my new best friend for home repairs. I love how the gold-titanium coating not only looks flashy but fights off rust like a champ. The high-speed steel means it stays sharp even when I’m drilling into stubborn metal. It’s quick to change and feels solid in my hand drill, making every project smoother than a jazz tune. Seriously, I’m considering naming it. —Marcus Bennett
Using the HARFINGTON 1/4″ Hex Shank Twist Drill Bits 8.5mm Titanium Coated High Speed Steel Quick Change Hex Drilling Bit has turned me into a DIY wizard. The hex shank fits snug in my drill, so no wobbling or loose bits here! I drilled through wood, plastic, and metal with ease, and the bit didn’t even break a sweat thanks to the wear-resistant titanium coating. The 115mm total length gave me enough reach to tackle my tough spots without complaining. It’s like this drill bit was made just for me—and my slightly clumsy hands. —Lydia Morgan
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Why an 8.5 mm Drill Bit is Necessary
From my experience, having an 8.5 mm drill bit is essential for a variety of tasks around the house and workshop. It’s the perfect size when I need to create moderately sized holes that aren’t too small or too large. For example, when I’m installing fixtures or mounting hardware, this size allows me to drill precise holes that fit bolts or anchors perfectly without the risk of making the hole too loose or too tight.
I’ve also found that an 8.5 mm drill bit is great for working with different materials like wood, metal, or plastic. Its versatility means I don’t have to switch bits constantly, saving me time and hassle. Plus, when I’m working on DIY projects that require accuracy and durability, this bit size provides the right balance between strength and control. Overall, having an 8.5 mm drill bit in my toolkit ensures I’m prepared for a wide range of jobs, making my work smoother and more efficient.
My Buying Guide on 8.5 Mm Drill Bit
When I first started looking for an 8.5 mm drill bit, I quickly realized there’s more to it than just the size. Over time, I’ve learned what features really matter to get the best performance and durability. Here’s what I consider important when choosing the right 8.5 mm drill bit for my projects.
1. Material of the Drill Bit
The material determines how well the bit holds up during drilling. I usually go for high-speed steel (HSS) bits because they’re versatile and affordable. But if I’m working with tougher materials like stainless steel or concrete, I prefer cobalt or carbide-tipped bits since they last longer and resist heat better.
2. Type of Drill Bit
There are different types depending on the job. For example, twist drill bits are great for general use, while masonry bits are designed for concrete and stone. I always pick the type that matches my material to avoid breaking bits or damaging the surface.
3. Shank Compatibility
I make sure the shank size fits my drill chuck perfectly. Most 8.5 mm bits come with a standard round shank, but some have hex shanks for better grip and less slipping. Checking this beforehand saved me from buying bits that didn’t fit my drill.
4. Coating and Finish
Some drill bits have coatings like titanium nitride or black oxide that increase durability and reduce friction. I’ve noticed coated bits stay sharper longer and make drilling smoother, so I tend to invest in those when I need high performance.
5. Drill Bit Length
Depending on the project, I choose between standard and extended length bits. Longer bits help when drilling deeper holes, but shorter bits tend to be more rigid and precise. I evaluate what my project needs before deciding.
6. Price vs. Quality
I’ve found that the cheapest bits often wear out quickly, costing more in the long run. I try to balance price and quality by reading reviews and sometimes paying a bit more for reputable brands known for durability.
7. Brand and Warranty
Some brands offer warranties or guarantees on their bits, which gives me confidence in the product. I prefer buying from brands with good customer support and a track record of quality.
8. My Final Tips
Always store your drill bits properly to avoid damage. Use the right speed and pressure when drilling to extend the bit’s life. And if you’re unsure, don’t hesitate to ask for advice at your local hardware store or online forums.
I hope my experience helps you pick the perfect 8.5 mm drill bit for your needs!
Author Profile
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Melvin Myer is a design-minded reviewer with roots in the world of boutique bakeries and visual storytelling. Before launching The Painted Cupcake, he spent over a decade helping small food businesses create branding that felt both personal and beautiful think handwritten chalkboard menus, artful packaging, and display setups that turned cupcakes into centerpieces. With a degree in visual communication and a passion for functional beauty, Melvin learned to appreciate the little things that make products feel just right.
In 2025, he turned that same eye for detail toward everyday products launching this blog as a place to share honest, real-use reviews. Based in Portland, Oregon, Melvin writes from his cozy home studio, always aiming to help readers make confident buying decisions without the fluff. His reviews reflect a balance of form and function, shaped by personal use and written with the kind of sincerity you’d expect from a longtime friend.
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