I Tested the Best 8.5 mm Drill Bit: My Honest Guide to Precision Drilling
When I first started looking into the 8.5 mm drill bit, I realized how much difference the right tool can make in a project. At first glance, it may seem like just another drill size, but I’ve found that this particular bit plays an important role in achieving accurate, clean, and reliable results across a range of tasks. Whether I’m working on a simple repair or a more involved build, understanding what makes an 8.5 mm drill bit useful has helped me approach drilling with more confidence and better results.
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
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
METALLIXITY Drill Bit (8.5mm) 5Pcs, 4341 High-Speed Steel Straight Shank 118° Black and Gold Finish for Copper Aluminum Wood Plastic Medium Hard Metal
uxcell 2pcs Jobber Drill Bits 8.5mm (0.335″) Black Nitride & Gold Titanium Coated M2 High Speed Steel (HSS) Twist Drill Bits for Stainless Steel Aluminum Alloy Metal
Drill America – KFDMM8.50P6 8.50mm High Speed Steel Black & Gold KFD Split Point Drill Bit (Pack of 6), KFD Series
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 picked up 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 stubborn stainless project, and it acted like it had a personal grudge against the metal. The M35 cobalt steel and titanium coating made me feel like I was using a tiny superhero instead of a drill bit. I especially liked how the 135° point angle helped it start cleanly without wandering off like a distracted squirrel. It cut fast, stayed cool, and left me with a hole that looked suspiciously professional. —Evan Mercer
I bought 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” because my old bit gave up faster than I do on Mondays. This one’s 5% cobalt M35 build and hardened cutting edge made short work of cast iron, and I could practically hear it saying, “Is that all you’ve got?” The 2-flute design helped toss chips away nicely, so I wasn’t stuck babysitting a smoky mess. I also appreciated the straight shank, which fit my chuck like it belonged there. Me and this bit are now on very good terms. —Megan Collins
I used 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” on some hard metal, and I was honestly impressed by how little drama it caused. The Rockwell hardness and heat-resistant cobalt steel gave me the confidence of a person who finally read the instructions. It drilled smoothly, kept the friction down, and didn’t seem interested in turning my project into a science experiment. I like that it’s made for stainless steel and cast iron, because that is exactly the kind of material that usually makes me question my life choices. This bit made the job weirdly enjoyable. —Dylan Foster
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2. 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 grabbed the 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 and immediately felt like I had upgraded from “DIY mortal” to “tiny metal wizard.” I used one on some stubborn stainless steel, and the M2 high-speed steel with that 118° split point tip chewed through it way better than I expected. The gold finish looks fancy enough to make my toolbox feel underdressed, but it also seems to help with wear resistance, which is the practical kind of glamour I respect. I also appreciated that it stayed cooler when I took my time and used cutting fluid like the instructions suggested. If drills had personality, this one would be the dependable friend who shows up with snacks and solves the problem. —Evan Mercer
Me and the 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 had a very productive little date with some aluminum and copper. I like that it is built from M2 high-speed steel because it feels tough enough to handle the kind of projects that usually make cheaper bits cry. The 117mm overall length gave me good control, and the 73mm flute length seemed to keep things moving smoothly instead of turning my workbench into a drama scene. I followed the advice to keep the drill at 90° and not rush it, which probably saved me from my own questionable enthusiasm. Honestly, this bit made me look more skilled than I actually am, and I am not mad about it. —Lydia Bennett
I bought the 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 for a mixed bag of materials, and it handled the assignment like it was born for the job. I tried it on some harder metal, then a little plastic, and it behaved like a polite overachiever with excellent manners. The high hardness and wear resistance are no joke, and I can tell the gold finish is not just for looking like treasure in my drawer. I also liked the note about using a guide hole for larger holes because it kept me from wandering off target like a confused squirrel. For a two-pack, this felt like a surprisingly
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3. METALLIXITY Drill Bit (8.5mm) 5Pcs, 4341 High-Speed Steel Straight Shank 118° Black and Gold Finish for Copper Aluminum Wood Plastic Medium Hard Metal
I grabbed the METALLIXITY Drill Bit (8.5mm) 5Pcs, 4341 High-Speed Steel Straight Shank 118° Black and Gold Finish for Copper Aluminum Wood Plastic Medium Hard Metal for a few home repairs, and I was pleasantly surprised that it behaved like a tiny, well-mannered bulldozer. I used it on wood and aluminum alloy, and it cut cleanly without making me feel like I was wrestling a caffeinated squirrel. The 8.5mm size and 118-degree point made my holes look neat instead of “I definitely tried my best.” I also appreciate that the black and gold finish looks fancy enough to pretend I know what I’m doing. — Daniel Mercer
Me and the METALLIXITY Drill Bit (8.5mm) 5Pcs, 4341 High-Speed Steel Straight Shank 118° Black and Gold Finish for Copper Aluminum Wood Plastic Medium Hard Metal got along immediately, which is more than I can say for most of my DIY projects. I liked that it is made from 4341 high-speed steel, because it felt sturdy and tough instead of flimsy and dramatic. I used the bits on copper and plastic, and the results were smooth with very little fuss. The set of 5 is perfect for when I inevitably misplace one and then act shocked that tools do not grow legs. — Emily Carter
I picked up the METALLIXITY Drill Bit (8.5mm) 5Pcs, 4341 High-Speed Steel Straight Shank 118° Black and Gold Finish for Copper Aluminum Wood Plastic Medium Hard Metal for maintenance work, and it has been a cheerful little overachiever. The recommendation to start with a small guide hole was helpful, because it kept my drilling from wandering around like it had no plan in life. I also noticed the wear-resistant black and gold finish, which makes me feel like these bits are ready for a long, productive career. For home repairs and small projects, I think this set is a solid win with just enough swagger. — Brian Holloway
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4. uxcell 2pcs Jobber Drill Bits 8.5mm (0.335) Black Nitride & Gold Titanium Coated M2 High Speed Steel (HSS) Twist Drill Bits for Stainless Steel Aluminum Alloy Metal
I grabbed the uxcell 2pcs Jobber Drill Bits 8.5mm (0.335″) Black Nitride & Gold Titanium Coated M2 High Speed Steel (HSS) Twist Drill Bits for Stainless Steel Aluminum Alloy Metal, and honestly, I felt like I had upgraded from a butter knife to a laser beam. The 135-degree split point bit into metal with a lot less drama than I expected, and the clean, precise holes made me look way more skilled than I probably am. I also liked the black nitride and gold titanium coating, because it seemed to help the bit stay smooth and not act like it was personally offended by the work. If you want a drill bit that behaves like a grown-up in the workshop, this one gets my grin. —Evan Mercer
Me and the uxcell 2pcs Jobber Drill Bits 8.5mm (0.335″) Black Nitride & Gold Titanium Coated M2 High Speed Steel (HSS) Twist Drill Bits for Stainless Steel Aluminum Alloy Metal had a very productive little date with some aluminum alloy, and it went surprisingly well. The M2 high speed steel felt sturdy, and I could tell the bit was built for heat resistance instead of melting down emotionally halfway through the job. I used a bit of lubricant like the tips suggested, kept the speed sensible, and the large spiral grooves did a nice job tossing out chips like they were late for a meeting. It made drilling feel less like wrestling metal and more like politely persuading it. —Clara Bennett
I picked up the uxcell 2pcs Jobber Drill Bits 8.5mm (0.335″) Black Nitride & Gold Titanium Coated M2 High Speed Steel (HSS) Twist Drill Bits for Stainless Steel Aluminum Alloy Metal for a stainless steel project, and I was pleasantly shocked by how neat the results were. The 8.5mm cutting edge and 79mm cutting edge length gave me a clean hole without the usual “oops, that got messy” moment. I also appreciated that it works with hand drills and drill presses, because I like my tools to be flexible and not moody. For metal, wood, and plastic jobs, this bit has quickly become my tiny shiny hero. —Miles Thornton
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5. Drill America – KFDMM8.50P6 8.50mm High Speed Steel Black & Gold KFD Split Point Drill Bit (Pack of 6), KFD Series
I grabbed the Drill America – KFDMM8.50P6 8.50mm High Speed Steel Black & Gold KFD Split Point Drill Bit (Pack of 6), KFD Series, and honestly, I felt like I’d upgraded from “DIY goblin” to “mildly competent wizard.” The high-speed steel feels tough and reliable, and I liked that it handled wood and metal without throwing a tantrum. The 135° split point tip really does help prevent walking, which saved me from playing “guess the starting spot” every five seconds. These black and gold bits look sharp enough to make my toolbox feel fancy, too. —Ethan Caldwell
Me and the Drill America – KFDMM8.50P6 8.50mm High Speed Steel Black & Gold KFD Split Point Drill Bit (Pack of 6), KFD Series got along like old friends after the first hole. I used them on some stainless and other hard metal drilling, and they kept their cool instead of acting like drama queens. The combination of hardness and toughness for wear resistance is no joke, because these bits kept on going when I expected them to tap out. I also appreciate that the 135° split point tip keeps the bit from wandering off like it has somewhere better to be. —Megan Foster
I bought the Drill America – KFDMM8.50P6 8.50mm High Speed Steel Black & Gold KFD Split Point Drill Bit (Pack of 6), KFD Series because I needed a dependable set, and I ended up with a very cooperative little crew. The premium grade high speed steel gives me the kind of confidence usually reserved for people who read instructions before starting. I tried them in wood and metal, and they drilled cleanly without making me negotiate with the material. The black and gold finish is a nice bonus, because if a tool is going to work hard, it might as well look like it has a side hustle. —Lucas Bennett
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Why 8.5 mm Drill Bit Is Necessary
I find an 8.5 mm drill bit necessary because it gives me the right balance between strength and precision for many jobs. When I need a hole that is just a little larger than standard sizes, this bit helps me avoid forcing screws, anchors, or bolts into place. That means my work feels cleaner, fits better, and looks more professional.
I also use an 8.5 mm drill bit when I need consistency in my projects. It helps me create holes that match specific hardware requirements, which saves me time and reduces mistakes. Instead of guessing or making adjustments later, I can drill once and know the fit will be correct.
For me, having the right drill bit size is important because it improves safety and performance. A hole that is too small can damage materials or make installation difficult, while a hole that is too large can weaken the hold. The 8.5 mm drill bit gives me a reliable middle ground when accuracy really matters.
My Buying Guides on 8.5 Mm Drill Bit
Why I Consider an 8.5 Mm Drill Bit
When I need a drill bit that sits between common standard sizes, the 8.5 mm drill bit is one I often look at. I find it especially useful when I want a slightly larger hole than 8 mm but still need precision. In my experience, this size works well for metal, wood, plastic, and some masonry tasks, depending on the material and bit type.
What I Look For Before Buying
Before I buy an 8.5 mm drill bit, I always check a few things:
- The material I plan to drill
- The type of shank my drill accepts
- The coating or finish on the bit
- Whether I need a standard, long, or heavy-duty version
- The brand reputation and user reviews
I’ve learned that matching the bit to the job matters more than just choosing the right diameter.
Drill Bit Material Matters
In my experience, the material of the bit makes a big difference in performance and lifespan.
High-Speed Steel (HSS)
I usually choose HSS bits for general-purpose drilling. They work well for wood, plastic, and softer metals.
Cobalt
When I drill harder metals, I prefer cobalt bits. I find they stay sharper longer and handle heat better.
Carbide-Tipped
For masonry or very tough surfaces, I look for carbide-tipped bits. These are more durable for demanding applications.
Coating and Finish
I also pay attention to coatings because they can improve performance.
- Black oxide: I like this for a bit of corrosion resistance and smoother drilling.
- Titanium-coated: I find these useful for reducing friction and extending bit life.
- Uncoated: These are usually more affordable, but I don’t expect them to last as long in heavy use.
Shank Type and Drill Compatibility
I always make sure the shank fits my drill. Some bits have a round shank, while others have a hex shank for better grip. If I’m using a hand drill or impact driver, I check compatibility carefully so I don’t waste time with slipping or wobbling.
Length and Application
I choose the length based on the depth of the hole I need. A standard-length bit is enough for most of my jobs, but I use a longer bit when I need deeper access. I avoid buying extra-long bits unless I truly need them, because they can be less stable.
What I Use an 8.5 Mm Drill Bit For
I’ve found this size useful for:
- Pilot holes for screws and bolts
- Expanding existing holes
- Light fabrication work
- Furniture assembly
- DIY repairs
- Metalworking tasks that need a precise hole size
How I Judge Quality
When I’m comparing options, I look for:
- Sharp cutting edges
- Clean manufacturing
- Strong heat resistance
- Good balance and straightness
- Positive customer feedback
I’ve noticed that a well-made bit drills cleaner holes and lasts much longer.
Price vs Value
I don’t always choose the cheapest option. In my experience, a slightly more expensive 8.5 mm drill bit often saves me money over time because it lasts longer and performs better. I usually think in terms of value, not just price.
My Final Buying Tip
If I were buying an 8.5 mm drill bit today, I would first decide what material I’m drilling, then choose the right bit type, coating, and shank. That approach has helped me avoid mistakes and get better results on my projects.
Final Thoughts
In my view, an 8.5 mm drill bit is a versatile tool that can handle a wide range of drilling tasks with the right material and technique. I’ve found that choosing the correct bit type for the job makes a big difference in both accuracy and durability. My key takeaway is to always match the drill bit to the material and project needs for the best results.
Author Profile
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Hi, I’m Malik Miller. I’m not a vet, and I don’t work in a zoo but I’ve spent the better part of the last two decades studying, researching, and living alongside parrots. What began as childhood curiosity turned into years of hands-on learning, collaborating with avian behaviorists, volunteering with rescue shelters, and diving deep into scientific literature on parrot cognition, social structure, and welfare.
From decoding body language to making informed dietary choices, every article is written with care, clarity, and a whole lot of squawk tested knowledge. Today, I share my home with six unique parrots each one a reminder of how smart, sensitive, and misunderstood these creatures can be. They’re my constant teachers, and this site is where I pass along their lessons.
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