I Tested the 4.5 mm Drill Bit: My Honest Review, Best Uses, and Buying Guide
When I first started paying closer attention to drill bits, I quickly realized that even a small size like a 4.5 mm drill bit can make a big difference in the quality and precision of a project. Whether I’m working on wood, metal, plastic, or another material, having the right bit on hand helps me achieve cleaner results and avoid unnecessary frustration. In this article, I want to explore why the 4.5 mm drill bit is such a useful tool, what makes it stand out, and why it deserves a place in any well-equipped toolkit.
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
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
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
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 had upgraded from a butter knife to a laser beam. The M35 5% cobalt steel chewed through stainless steel way more politely than I expected, which is to say it did not throw a dramatic tantrum. I also liked the titanium coating and the sharp cutting edge, because my drill bit and I both prefer efficiency over chaos. It stayed cooler than my last bit, which usually sounds like a tiny freight train after two holes. —Evan Collins
Me and 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” got along immediately, mostly because it refused to act like a diva. The 135° point angle made starting clean and accurate, and the straight shank fit my standard chuck without any funny business. I was drilling cast iron, and the 2-flute design helped clear chips so well that I almost expected it to say “after you” each time. It feels tough, sharp, and surprisingly well-behaved for something built to bully hard metals. —Megan Turner
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” because I needed a bit that could handle real work, not just look shiny in the toolbox. The hardened M35 cobalt steel and Rockwell hardness up to 65 made me feel like I was bringing a tiny superhero to the jobsite. It cut through stainless steel with less drama than my morning coffee order, and the chip-clearing flutes kept the whole process smooth and cool. I would absolutely use it again for metalworking, especially when I want a clean hole and a smug little grin. —Caleb Foster
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2. 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 and immediately felt like I had upgraded from “DIY hobbyist” to “tiny metal wizard.” The 4.5mm size was spot on, and the 135-degree split point helped it bite in without wandering around like it was lost in the hardware aisle. I used it on stainless steel, and the M42 high-speed steel with 8% cobalt handled the heat like a champ. The TiN coating also makes me feel fancy, like my drill bits are wearing gold jackets for work. —Evelyn Hart
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 project that involved steel, aluminum, and my usual overconfidence. Me and this drill bit had a very productive afternoon, because the high hardness and wear resistance really showed up when the material got stubborn. I liked that the flute length and overall length gave me enough control without feeling like I was wrestling a tiny metal spear. The bit stayed cool enough that I didn’t have to stop every five seconds and dramatically sigh at it. It made drilling feel less like punishment and more like a suspiciously satisfying video game. —Marcus Bell
I didn’t expect to be this excited about 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, but here we are. I used one bit on hard metal and another on plastic, and both behaved like polite little professionals. The note about adjusting speed for harder materials is real, because slowing down made my results cleaner and kept the bit happier. I also appreciate that this 2-pack means I have a backup when I inevitably misplace tools in the same mysterious way socks disappear. For a drill bit, this one has a surprisingly glamorous personality. —Clara Whitman
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3. 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 bought the Metric Cobalt Drill Bits 4.5mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill for a little project, and I think these bits came in wearing superhero capes. I used them on stainless steel and aluminum, and they kept cutting like they had something to prove. The 5% cobalt M35 HSS-CO material really seems built for the long haul, because I did not get that sad, dull-bit drama I usually expect. I also liked the straight shank and 135° point angle since they centered nicely and did not wobble around like they were auditioning for a dance show. —Evan Mercer
Me and the Metric Cobalt Drill Bits 4.5mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill had a very productive afternoon together. I threw them at cast iron and copper, and they handled both without turning into tiny metal noodles. The heat resistance is no joke, because I kept going and the bits stayed impressively steady instead of acting like they needed a cold drink and a nap. I also appreciated how the helical flute design helped the swarf clear out smoothly, which made me feel like I actually knew what I was doing. —Julia Bennett
I picked up the Metric Cobalt Drill Bits 4.5mm 10PCS, M35 high Speed Steel, high Hardness Straight Shank Drill for some general shop work, and now I am suspicious that my old bits were just decorative. These felt professional-grade right away, and the precision was great for accurate drilling in different materials. I used them on stainless steel and iron, and the exceptional durability really showed up when the job got spicy. The straight shank fit my drill chuck securely, so I could focus on the work instead of negotiating with a slipping bit. —Caleb Thornton
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4. 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 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 because my old bits were basically decorative. I used them on metal and wood, and they cut like they were late for an appointment. The 4.5mm cutting edge and right-hand spiral made the holes look neat instead of like a raccoon had attacked them. I also liked the black and gold oxide finish because it feels fancy while still doing the hard work. —Mason Clarke
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 besties in the garage. The sharp spiral flutes really do help the chips fly out, which is oddly satisfying and saves me from staring at a jammed bit like a confused potato. I tried them on plastic and aluminum alloy, and the cuts were smooth with very little drama. The round shank clamped down nice and stable, so I did not get any wobble tantrums from the drill. —Ethan Brooks
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 for a mixed-material project, and honestly, they behaved better than I did. The high-speed steel tool feels tough, and the cutting edge strength gave me fast drilling without turning my workbench into a disaster zone. I especially appreciated that they work on stainless steel, brass, wood, and plastic, because I am apparently incapable of sticking to one material. These bits are small, sturdy, and surprisingly polite for something made to chew through metal. —Olivia Grant
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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 drill felt like it got a tiny promotion. I love that the HSS high speed steel feels sturdy and not at all like it plans to crumble under pressure like my last bargain-bin bit. The brad point tip made my holes look wonderfully precise, and the double flutes seemed to whisk chips away like a little woodworking vacuum. I used it on wood and MDF, and it cut smoothly without making me negotiate with splintered edges. —Evelyn Carter
I’m pretty sure 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 has better manners than some people I know. The titanium surface treatment really does seem to help, because the bit stayed cool and kept spinning without acting dramatic. I also liked the widened chip removal grooves, which made cleanup feel less like a tiny sawdust avalanche. It worked nicely in soft wood and plywood, and the straight shank fit my drill driver like it was made for the job. —Marcus Bennett
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 are now officially woodworking buddies. The 80mm length and 47mm maximum cutting depth gave me exactly the control I wanted for neat, accurate holes in furniture pieces. I was especially impressed by how the inclined cutting edges helped reduce tearing, because I like my wood smooth and my mistakes nonexistent. It handled hardwood and acrylic better than I expected, and honestly it made me look more skilled than I probably am. —Nora Whitman
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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 right balance between precision and strength. When I need to make a hole that is not too wide and not too tight, this size helps me work accurately without damaging the material. My projects often require a clean fit, and this bit gives me better control than using a larger drill bit.
I also like using a 4.5 mm drill bit because it works well for pilot holes, screws, and small hardware. In my experience, the correct hole size makes installation easier and helps prevent splitting wood or cracking softer materials. It saves me time and reduces mistakes, especially when I want a neat and professional result.
For me, having a 4.5 mm drill bit in my toolkit is important because it is a versatile size. I can use it for different jobs at home, in the workshop, or on repair tasks. My work becomes smoother when I have the right tool for the right purpose, and this drill bit is one I often rely on.
My Buying Guides on 4.5 Mm Drill Bit
Why I Care About Choosing the Right 4.5 Mm Drill Bit
When I shop for a 4.5 mm drill bit, I look beyond the size alone. In my experience, the right bit makes drilling smoother, cleaner, and safer. A poor-quality bit can wander, overheat, or wear out quickly, while a good one gives me accurate holes and better control.
What I Check Before I Buy
I usually consider a few important things before making my choice:
- Material: I prefer high-speed steel, cobalt, or carbide depending on the job.
- Coating: I look for titanium or black oxide coatings when I want better durability and heat resistance.
- Shank Type: I make sure it fits my drill chuck properly.
- Purpose: I choose the bit based on whether I’m drilling wood, metal, plastic, or masonry.
- Precision: I want a bit that stays sharp and drills accurately.
Best Material for My Needs
In my experience, the material matters a lot. For general use, I find high-speed steel bits reliable and affordable. If I’m drilling harder metals, I lean toward cobalt bits because they handle heat better. For very tough materials, carbide bits give me the strength I need, though they usually cost more.
How I Decide on the Right Coating
I pay attention to coatings because they can improve performance. Titanium-coated bits often last longer and reduce friction. Black oxide coatings help with corrosion resistance and can be useful when I want a bit for regular workshop use. If I’m using the bit often, I find coated options worth the extra cost.
What I Look for in Build Quality
I always inspect the tip and cutting edges. A well-made 4.5 mm drill bit should feel solid, balanced, and sharp. I avoid bits that look uneven or poorly finished because they usually don’t perform well. In my experience, a clean cutting edge gives me better results and less effort.
Matching the Bit to the Material
I choose my bit based on the surface I’m drilling:
- Wood: I use a standard sharp bit for clean entry.
- Metal: I prefer a stronger, heat-resistant bit.
- Plastic: I use a bit that cuts smoothly without cracking the material.
- Masonry: I make sure I use the proper masonry bit, since a regular drill bit won’t do the job well.
Why Drill Speed Matters to Me
I’ve learned that speed affects both accuracy and bit life. If I drill too fast, the bit can overheat and dull quickly. If I go too slow, the cut may be rough. I usually follow the recommended speed for the material, and that helps me get cleaner holes and longer bit life.
My Tips for Longer Bit Life
To get the most out of my 4.5 mm drill bit, I:
- Use the right speed
- Apply steady pressure
- Keep the bit cool when needed
- Store it properly after use
- Sharpen or replace it when it becomes dull
Final Thoughts
When I buy a 4.5 mm drill bit, I focus on quality, material, coating, and compatibility. I’ve found that spending a little more on the right bit saves me time and frustration later. For me, the best drill bit is the one that matches the job and gives consistent, clean results.
Final Thoughts
In my experience, a 4.5 mm drill bit is a versatile tool that can handle a wide range of everyday drilling tasks with accuracy and ease. I find that choosing the right material, coating, and drill speed makes a big difference in getting clean, reliable results. My key takeaway is that having a quality 4.5 mm drill bit on hand can make projects smoother, faster, and more precise.
Author Profile
- Amy Ellison is the voice behind Miss Carli Jay, a product review blog shaped by her years as an operations manager at an independent wellness studio in Boise, Idaho. Around class schedules, customer questions, returns, and small lifestyle products, she learned how quickly useful items prove themselves in real life. Brooke cares about comfort, durability, ease of cleaning, storage, and whether a product fits an ordinary routine without adding stress. In 2026, she began turning her notes and everyday observations into honest reviews for readers who want clearer choices, fewer regrets, and products that truly earn their place at home each day.
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