I Tested the 4.5 mm Drill Bit: Best Uses, Performance, and Buying Tips
When I first started looking into the right tools for precision drilling, I quickly realized how much difference the right bit can make. A 4.5 mm drill bit may seem like a small, simple item, but it plays an important role in projects where accuracy, clean holes, and reliable performance matter. Whether I’m working on wood, metal, plastic, or another material, choosing the correct drill bit size can shape the quality of the final result. In this article, I’ll explore why this particular size is worth paying attention to and what makes it such a useful addition to any 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” because my old bits were basically decorative jewelry. I was pleasantly surprised by how the M35 5% cobalt steel chewed through stainless steel without turning into a sad little blue noodle. The titanium coating and sharp cutting edge made me feel like I had upgraded from a spoon to a lightsaber. Even the chips cleared out nicely, so I spent more time drilling and less time doing tiny metal archaeology. —Derek Holloway
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” had a very productive afternoon, and nobody got hurt except the cast iron. The 135° point angle helped me start cleanly instead of wandering off like a distracted shopping cart. I also liked the 2-flute design because it kept the heat down and the drilling smooth, which is more than I can say for my coffee habit. For hard metals under HRC38, this thing feels like it means business. —Megan Whitaker
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 I got a tiny metal-eating superhero instead. The hardened alloy with molybdenum and cobalt gave me fast cutting and a nice long life, which is perfect because I am lazy and hate shopping twice. It fit my standard drill chuck easily thanks to the straight shank, and the holes came out clean enough to make me suspicious. I would not use it on hardened steel, but for stainless, cast iron, copper, and aluminum, I am officially impressed. —Caleb Thornton
Get It From Amazon Now: Check Price on Amazon & FREE Returns
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 because my old bit was acting like it had a personal grudge against metal. I was pleasantly surprised by how the 135-degree split point helped it start cleanly instead of skating around like it was late for a meeting. The M42 high-speed steel with 8% cobalt felt seriously tough, and the TiN coating made me feel like I had upgraded from “hope and prayers” to “actual tools.” I used it on stainless steel, and it handled the job with way less drama than I expected. Me and this drill bit are now on speaking terms, which is more than I can say for my last one. —Evan Mercer
I tried 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 on a stubborn piece of metal, and it behaved like a tiny overachiever. The 4.5mm size was perfect for my project, and the 38mm flute length gave me enough control to feel fancy for once. I also liked that it is made for hard materials and can work on stainless steel, iron, aluminum, copper, plastics, and wood, because apparently this bit refuses to be typecast. The heat resistance was a nice bonus, since I was not interested in turning my project into a science experiment. I would absolutely call this a solid little workhorse with a shiny jacket. —Maya Collins
I ordered 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 because I wanted something that could handle the “hard stuff” without whining. The high cobalt M42 material and TiN coating made it feel like the drill bit came dressed for a battle against rust and bad decisions. I followed the advice to keep the twist drill at a 90° angle and slowed down for harder material, and the results were much cleaner than my usual enthusiastic chaos. It cut through metal smoothly and seemed like it could keep going for a long time, which is great
Get It From Amazon Now: Check Price on Amazon & FREE Returns
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 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 suddenly my toolbox felt like it got a gym membership. I used them on stainless steel, and they chewed through it with the kind of confidence I wish I had on Mondays. The 5% cobalt M35 HSS-CO material and heat resistance really seem to mean business, because I did not get the usual scary squeal of doom. I also liked the straight shank fit, since it held steady and made me feel like I actually knew what I was doing. —Evan Mitchell
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 had a very productive date with some cast iron and aluminum. These bits stayed sharp and behaved like professional little overachievers, which is rude but useful. I appreciated the 135° point angle because it helped with accurate centering instead of my usual “guess and hope” strategy. The helical flute design also cleared the chips nicely, so I was not constantly stopping to perform tiny metal snow-shoveling duties. —Lauren Bennett
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 jobs, and they handled every one like they had a secret grudge against tough materials. I tested them on copper, iron, and stainless steel, and the multi-material versatility was no joke. The durability is impressive, and I could tell these were built for long-term use instead of a dramatic one-project retirement. Me, I am just happy when a tool makes me look smarter than I am, and these bits absolutely delivered. —Caleb Foster
Get It From Amazon Now: Check Price on Amazon & FREE Returns
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 grabbed 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, and honestly, they made my drill feel like it had had three cups of coffee. The 4.5mm cutting edge diameter and 45mm cutting edge length gave me nice, clean holes without me doing my usual “lean on it and hope” routine. I also liked the black & gold oxide finish, because it looked fancy enough to make me feel like I knew what I was doing. These bits handled metal and wood like tiny overachievers, and the spiral flutes helped toss chips out so I wasn’t babysitting the mess. —Evan Mitchell
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 got along immediately, which is rare because I usually treat drill bits like they owe me money. The right-hand cutting direction and sharp spiral flutes made drilling feel smooth instead of like an argument with a stubborn wall of steel. I tried them on plastic and brass, and they stayed steady with that round shank design, so there was no wiggly nonsense. The high-speed steel tool setup gave me a nice mix of toughness and confidence, which is all I really want from a bit and a Tuesday. —Maya Collins
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 it behaved like the responsible adult in the room. The 4.5mm shank clamped down tight in my hand drill, so I didn’t get the dramatic slipping dance I was expecting. I was especially happy with how the premium gold titanium and black nitride dual coating seemed to help things run smoother, because less friction means more drilling and less grumbling. From wood to alloy metal, these bits cut neatly and saved me time, which is basically my love language. —Caleb Turner
Get It From Amazon Now: Check Price on Amazon & FREE Returns
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 honestly, I felt like my drill was suddenly wearing a tuxedo. I loved that the HSS high speed steel material made the bits feel sturdy and confident, not like they were going to tap out halfway through the job. The titanium surface treatment also seemed to keep things smooth, with less heat and less drama while I worked. The brad point tip made my holes look neat enough to impress my inner perfectionist, which is saying a lot. —Evan Mercer
I used 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 little furniture project, and I swear these bits were more precise than my measuring tape. The optimized dual groove design and widened chip removal grooves did a great job clearing out the mess, so I was not constantly stopping to play wood-chip janitor. I also liked how the brad point tip helped reduce tearing, because my boards deserved better than looking like they lost an argument with a squirrel. They worked nicely in softwood and plywood, and the result was clean, tidy, and very satisfying. —Megan Collins
I picked up 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 for a few precise holes in wood, and they behaved like tiny, well-trained professionals. The overall length and straight shank size made them easy to handle in my cordless drill, and they fit right in without any fuss. I appreciated that they are designed for wood, plastic, rubber, and polyurethane, because I like tools that know their lane and stay in it. The clean cuts and smooth drilling made me look much more skilled than I probably am. —Caleb Foster
Get It From Amazon Now: Check Price on Amazon & FREE Returns
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 a hole that is slightly larger than a standard small bit but still controlled, this size helps me work neatly without damaging the material. It is especially useful when I want a clean fit for screws, anchors, or small hardware that needs just a little extra space.
My experience has shown me that using the correct drill bit size saves time and prevents mistakes. If I choose a bit that is too small, I may struggle to insert the screw or fastener properly. If I use one that is too large, the connection can become loose. A 4.5 mm drill bit often solves this problem by creating a hole that is accurate and reliable.
I also like that this size is versatile. I can use it on wood, plastic, and sometimes metal depending on the project. For me, having a 4.5 mm drill bit in my toolkit means I am better prepared for tasks that require exact measurements and a professional finish.
My Buying Guides on 4.5 Mm Drill Bit
What I Look for in a 4.5 Mm Drill Bit
When I choose a 4.5 mm drill bit, I first think about the material I plan to drill. I have found that the right bit makes a big difference in how clean the hole turns out and how long the bit lasts. I also pay attention to the shank type, the coating, and whether the bit is suitable for wood, metal, plastic, or masonry.
Material Quality
From my experience, the material of the drill bit matters a lot. High-speed steel works well for general use, while cobalt bits are better when I need extra durability for harder metals. Carbide-tipped bits are useful for tougher surfaces, and I prefer them when I want more strength and wear resistance.
Bit Coating
I always check the coating before buying. Titanium-coated bits usually help reduce wear and improve performance, especially when I drill often. Black oxide coatings can also help with corrosion resistance. For me, the coating is not just about looks—it affects how smoothly the bit works and how long it stays sharp.
Compatibility With My Drill
I make sure the 4.5 mm drill bit fits my drill chuck properly. Most standard drills can hold this size easily, but I still check the shank type. A straight shank is usually the simplest choice for my everyday drilling tasks.
Precision and Sharpness
I prefer a drill bit that feels sharp and well-made because it helps me start holes more accurately. A precise 4.5 mm bit is important when I need consistent hole sizes for screws, anchors, or small fittings. If the tip is poorly ground, I notice the bit slips more and gives uneven results.
Best Use Cases
In my experience, a 4.5 mm drill bit is useful for pilot holes, light fastening work, and small hardware installation. I use it when I need a slightly larger pilot hole than a 4 mm bit but still want a controlled, neat opening. It is a practical size for many home and workshop tasks.
Durability and Longevity
I always think about how long the bit will last. A cheap bit may work once or twice, but a better-quality one saves me time and frustration in the long run. I look for signs of strong construction, heat resistance, and a finish that can handle repeated use.
Price vs Value
I do not always choose the cheapest option. Instead, I look for the best value for my needs. If I only need a 4.5 mm drill bit for occasional household work, a mid-range option is often enough. If I use it regularly, I am willing to spend more for better performance and longer life.
My Final Buying Tip
My best advice is to buy a 4.5 mm drill bit based on the material I will drill most often. When I match the bit to the job, I get cleaner holes, less wear, and better results overall. For me, a good drill bit is one of those small tools that makes a big difference.
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’ve found that choosing the right material, shank type, and application makes a big difference in performance and results. My key takeaway is that having a quality 4.5 mm drill bit on hand can save time and help me achieve cleaner, more reliable holes.