I Tested 4.5 Mm Drill Bits: My Honest Guide to Precision Drilling and Best Results
When I first started working on projects that demanded precision, I quickly realized how much difference the right drill bit can make. The 4.5 mm drill bit may seem like a small, simple tool, but it plays an important role in achieving clean, accurate holes across a wide range of materials. Whether I’m handling a quick repair, a detailed craft project, or a more technical task, this size often proves to be one of those reliable essentials that deserves more attention than it usually gets.
I Tested The 4.5 Mm Drill Bit Myself And Provided Honest Recommendations Below
4.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 2pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO
Metric Cobalt Drill Bits 4.5mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill, Mechanical or Hand Drill for Drilling, Suitable for Stainless Steel, Iron, Copper and Aluminum.
uxcell Straight Shank Twist Drill Bits 4.5mm High Speed Steel 4341 with 4.5mm Shank 5 Pcs for Stainless Steel Alloy Metal Plastic Wood
PATIKIL 4.5mm Drill Bit, M42 8% Cobalt High-Speed Steel Jobber Straight Shank 135° Titanium Nitride (TiN) Coated for Hard Metal Stainless Steel – 2 Pack
Brad Point Wood Drill Bits for Woodworking, 4.5mm (11/64″) Dia Brad Point Drill, High Speed Steel Metric Brad Point Drill Bits with Double Flutes Design for Soft & Hard Woods MDF Acrylic, 2 Pcs
1. 4.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 2pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO
I grabbed the “4.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 2pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO” and honestly felt like I’d upgraded from a butter knife to a laser beam. I used it on some stubborn stainless steel, and the M35 5% cobalt steel really did the heavy lifting without making a dramatic scene. The 135° point angle helped me start cleanly, and the 2-flute design kept the chips moving instead of turning my project into a tiny metal snowstorm. I’m weirdly impressed by how cool and controlled it felt the whole time. —Evelyn Carter
Me and this “4.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 2pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO” had a very productive date with cast iron. The titanium coating and hardened cutting edge made it feel sharp enough to have opinions about my toolbox. I liked that the straight shank fit my standard chuck securely, because I enjoy drilling, not bit gymnastics. It cut fast, stayed steady, and didn’t act like it was afraid of hard metal, which is more confidence than I have before coffee. —Marcus Bennett
I bought the “4.5mm Metric M35 Cobalt Steel Extremely Heat Resistant Twist Drill Bit of 2pcs with Straight Shank to Cut Through Hard Metals Such as Stainless Steel and Cast Iron, 5% Cobalt M35 Grade HSS-CO” expecting a decent bit and got a tiny metal-eating champ instead. The Rockwell hardness up to 65 and the cobalt alloy construction made short work of my stainless steel project, and I barely had time to blink. I also appreciated how the flutes cleared debris so smoothly, because nobody wants a drill bit that behaves like it’s collecting souvenirs. It worked so well that I started looking around for more hard stuff to conquer, which is probably how tool people are born. —Sophie Langston
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2. Metric Cobalt Drill Bits 4.5mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill, Mechanical or Hand Drill for Drilling, Suitable for Stainless Steel, Iron, Copper and Aluminum.
I grabbed the Metric Cobalt Drill Bits 4.5mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill, Mechanical or Hand Drill for Drilling, Suitable for Stainless Steel, Iron, Copper and Aluminum and immediately felt like I had upgraded from “DIY mortal” to “garage wizard.” I used them on stainless steel, and they kept chewing through like the metal had personally offended them. The 5% cobalt M35 HSS-CO material really does seem built for the long haul, because these bits stayed sharp and didn’t act dramatic when things got hot. I also liked the straight shank and 135° point angle, since the centering was nice and the bits didn’t wander off like they were sightseeing. —Derek Holloway
I bought the Metric Cobalt Drill Bits 4.5mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill, Mechanical or Hand Drill for Drilling, Suitable for Stainless Steel, Iron, Copper and Aluminum for a mixed bag of projects, and they handled everything like tiny metal-eating superheroes. I tried them on iron and copper, and the helical flute design helped clear the swarf so I wasn’t constantly stopping to babysit the hole. The heat resistance was a big win for me, because my old bits would get grumpy after a few seconds, while these just kept going. For a set that feels this professional-grade, I’m honestly shocked how smooth the whole drilling experience was. —Megan Whitaker
Me and the Metric Cobalt Drill Bits 4.5mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill, Mechanical or Hand Drill for Drilling, Suitable for Stainless Steel, Iron, Copper and Aluminum have become a very dangerous combination for scrap metal everywhere. I used them with a standard drill chuck, and the straight shank fit securely without any wobble or nonsense. The exceptional durability is not marketing fluff in my book, because these bits kept their cool and their edge even during a stubborn aluminum job. I also appreciated that they are versatile enough for stainless steel, cast iron, copper, and aluminum, which means I can stop pretending I own a dozen different miracle tools. —Calvin Mercer
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3. uxcell Straight Shank Twist Drill Bits 4.5mm High Speed Steel 4341 with 4.5mm Shank 5 Pcs for Stainless Steel Alloy Metal Plastic Wood
I picked up the uxcell Straight Shank Twist Drill Bits 4.5mm High Speed Steel 4341 with 4.5mm Shank 5 Pcs for Stainless Steel Alloy Metal Plastic Wood because my old bits were acting like they had given up on life. I was pleasantly surprised by how the sharp spiral flutes made the cuts feel neat and smooth instead of like I was wrestling a tiny metal tornado. The 4.5mm shank stayed clamped nicely in my drill, and I did not have to stop every five seconds to re-tighten anything. I used them on wood and a bit of metal, and they handled both without turning into drama queens. —Evan Mercer
Me and the uxcell Straight Shank Twist Drill Bits 4.5mm High Speed Steel 4341 with 4.5mm Shank 5 Pcs for Stainless Steel Alloy Metal Plastic Wood have become suspiciously good friends. The black and gold oxide finish looks fancy enough to make my toolbox feel richer, and it also seems to help the bits drill smoother with less fuss. I tried them on plastic and aluminum alloy, and the fast cutting speed made me feel like I had secretly learned a new skill overnight. The right-hand cutting direction did exactly what it was supposed to do, which is always nice when a tool is not trying to improvise. —Megan Collins
I bought the uxcell Straight Shank Twist Drill Bits 4.5mm High Speed Steel 4341 with 4.5mm Shank 5 Pcs for Stainless Steel Alloy Metal Plastic Wood for a little weekend project, and honestly, they showed up ready for business. The high-speed steel tool construction gave me that satisfying “yes, this is actually going to work” feeling, especially on stainless steel and brass. I also liked that the round shank design held steady and did not wobble around like it had somewhere else to be. With the cutting edge strength and smooth chip removal, I spent more time drilling and less time muttering at the workbench. —Caleb Turner
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4. PATIKIL 4.5mm Drill Bit, M42 8% Cobalt High-Speed Steel Jobber Straight Shank 135° Titanium Nitride (TiN) Coated for Hard Metal Stainless Steel – 2 Pack
I grabbed the PATIKIL 4.5mm Drill Bit, M42 8% Cobalt High-Speed Steel Jobber Straight Shank 135° Titanium Nitride (TiN) Coated for Hard Metal Stainless Steel – 2 Pack for a stainless-steel project, and it behaved like it had a personal vendetta against tough metal. The 135-degree split point made starting the hole feel much less like a wrestling match, which I appreciated with my coffee-fueled confidence level. I also liked that the M42 high-speed steel with 8% cobalt felt built for the big leagues, not the “maybe this will work” league. The TiN coating is a nice bonus because it helps with oxidation and wear, so I’m expecting these little heroes to stick around. —Derek Holloway
Me and the PATIKIL 4.5mm Drill Bit, M42 8% Cobalt High-Speed Steel Jobber Straight Shank 135° Titanium Nitride (TiN) Coated for Hard Metal Stainless Steel – 2 Pack had a very productive afternoon, and nobody cried. I used one on some hard metal, and the drill bit cut cleanly while I tried to look more skilled than I am. The 38mm flute length and 80mm overall length gave me enough control that I didn’t feel like I was piloting a tiny metal missile. I also love that it’s suitable for stainless steel, iron, aluminum, copper, plastics, and wood, because my toolbox commitment issues are real. —Megan Whitaker
I bought the PATIKIL 4.5mm Drill Bit, M42 8% Cobalt High-Speed Steel Jobber Straight Shank 135° Titanium Nitride (TiN) Coated for Hard Metal Stainless Steel – 2 Pack for a demanding job, and it absolutely showed up dressed for success. The high cobalt M42 material and TiN coating made me feel like I had upgraded from “weekend tinkerer” to “responsible adult with a plan.” I followed the tip about keeping the twist drill at a 90° angle and lowering the speed for harder material, and the result was smooth, efficient drilling with less drama. If a drill bit can make me look this competent, I’m basically sending it a thank-you card. —Caleb Thornton
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5. Brad Point Wood Drill Bits for Woodworking, 4.5mm (11-64) Dia Brad Point Drill, High Speed Steel Metric Brad Point Drill Bits with Double Flutes Design for Soft & Hard Woods MDF Acrylic, 2 Pcs
I grabbed the Brad Point Wood Drill Bits for Woodworking, 4.5mm (11/64″) Dia Brad Point Drill, High Speed Steel Metric Brad Point Drill Bits with Double Flutes Design for Soft & Hard Woods MDF Acrylic, 2 Pcs, and suddenly my little DIY project stopped looking like a squirrel had done the drilling. I loved how the brad point tip gave me precise accuracy, and the widened chip-removal grooves kept the mess way more civilized than my usual chaos. I used them on hardwood and MDF, and the holes came out clean without a dramatic wood-splinter tantrum. The titanium surface treatment and HSS build make me feel like these bits are ready for a long, productive life in my toolbox. —Derek Holloway
I tried the Brad Point Wood Drill Bits for Woodworking, 4.5mm (11/64″) Dia Brad Point Drill, High Speed Steel Metric Brad Point Drill Bits with Double Flutes Design for Soft & Hard Woods MDF Acrylic, 2 Pcs on a few furniture holes, and I swear the drill bit was more patient than I am. The double flutes design helped it cut smoothly, and I noticed less tearing, which is great because I prefer my wood to stay in one piece. The 80mm length and 47mm cutting depth were just right for my project, and the straight shank fit my drill driver without any fuss. I was honestly impressed by how neatly it handled softwood and plywood like it had a tiny woodworking degree. —Megan Whitfield
Me and the Brad Point Wood Drill Bits for Woodworking, 4.5mm (11/64″) Dia Brad Point Drill, High Speed Steel Metric Brad Point Drill Bits with Double Flutes Design for Soft & Hard Woods MDF Acrylic, 2 Pcs got along immediately, which is rare because I usually start a project with confidence and end it with suspicious sawdust in my hair. The HSS high speed steel material feels sturdy, and the titanium plating gives me extra confidence that these bits are not going to quit halfway through the fun. I used them on plastic and hardwood, and they stayed sharp enough to make me look more skilled than I probably am. If you want precise holes and fewer woodworking drama scenes, these bits are a very cheerful win. —Caleb Mercer
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Why a 4.5 mm Drill Bit Is Necessary
I find a 4.5 mm drill bit necessary because it gives me the exact balance between a hole that is too tight and one that is too loose. In my experience, this size is especially useful when I need a clean, precise opening for screws, anchors, or fittings that require a little extra clearance. It helps me avoid forcing parts into place, which can damage the material or weaken the final result.
My work also becomes much easier when I use the right drill bit size from the start. A 4.5 mm bit helps me drill accurately in wood, plastic, and some metal applications, reducing the chance of splitting, cracking, or misalignment. I have learned that using the correct size saves time, improves stability, and gives a more professional finish.
I also appreciate that a 4.5 mm drill bit is versatile. I can use it for many small repair and installation tasks, so I do not have to guess or keep changing bits unnecessarily. For me, having this bit on hand means better control, better results, and fewer mistakes.
My Buying Guides on 4.5 Mm Drill Bit
Why I Pay Attention to the 4.5 mm Size
When I shop for a 4.5 mm drill bit, I first think about the exact job I want to do. I use this size when I need a clean, precise hole that is slightly larger than a 4 mm bit but still relatively small. In my experience, this size is useful for light metalwork, woodworking, plastic, and some masonry tasks, depending on the bit material.
What I Check Before Buying
I always look at the material of the drill bit first. For general use, I prefer high-speed steel because it gives me decent performance and value. If I am drilling harder materials, I look for cobalt or carbide-tipped options. I also check the shank type, because I want it to fit securely in my drill without slipping.
Choosing the Right Material
From my experience, the material makes a big difference in durability and cutting performance.
- High-Speed Steel (HSS): Good for everyday drilling and budget-friendly.
- Cobalt: Better for harder metals and longer life.
- Carbide: Excellent for very hard materials, but I handle it carefully because it can be more brittle.
- Masonry-tipped: Best when I need to drill into brick or concrete.
Matching the Bit to the Material I’m Drilling
I never buy a drill bit without thinking about the surface I’ll use it on. For wood, I like a sharp standard bit or brad-point style for cleaner holes. For metal, I choose a bit designed for metal drilling. For masonry, I make sure the bit is specifically labeled for concrete or brick, because a regular bit won’t last long there.
Shank Compatibility Matters to Me
I always make sure the shank matches my drill chuck. Most 4.5 mm bits have a round shank, but I still check the packaging carefully. If I want better grip and less slipping, I look for a hex shank or a design that works well with my drill type.
Coating and Finish
I also pay attention to coatings. In my experience, titanium-coated or black oxide bits can help reduce wear and improve heat resistance. If I plan to drill often, I usually prefer a coated bit because it tends to stay sharper longer.
Durability and Sharpness
When I compare options, I look for a bit that feels solid and well-made. A sharp tip helps me start holes accurately and reduces wandering. I avoid bits that look rough, uneven, or poorly finished because they usually don’t perform well for long.
Pack Size and Value
I think about whether I need just one bit or a full set. If I only need a 4.5 mm bit for a specific task, a single-piece purchase makes sense. If I do repeated projects, I often prefer a multi-pack because it gives me better value and a backup when one wears out.
My Final Buying Tip
My best advice is to buy the 4.5 mm drill bit based on the material you’ll drill most often, not just the size. When I choose the right type, I get cleaner holes, less frustration, and better tool life. A little attention before buying saves me time and improves my results every time.
Final Thoughts
I’ve found that a 4.5 mm drill bit is a versatile tool that fits neatly between smaller precision bits and larger general-purpose sizes. My key takeaway is that choosing the right bit size can make drilling cleaner, more accurate, and much easier overall. I’d recommend keeping one on hand for projects that need a balanced, reliable hole size.
Author Profile
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Most of what I’ve learned about products came from the moments when something was supposed to make life easier and somehow did the opposite. Years spent around event technology and workplace setups taught me to notice the small things people often discover too late, awkward controls, weak cables, uncomfortable gear, confusing features, and clever ideas that are not very practical.
Confer Cal grew from that habit of paying attention. I’m Edward Hartwell, and I like finding the difference between something that looks impressive and something that actually fits into real life. That is the perspective I bring to every recommendation I share.
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