I Tested the Left Handed Cobalt Drill Bit: My Honest Take on Its Power and Precision

AvatarByMiles Harlan

I’ve always found that the smallest tools can make the biggest difference, and the Left Handed Cobalt Drill Bit is a perfect example of that. At first glance, it may seem like just another specialized bit, but it plays a surprisingly important role in tackling stubborn drilling jobs, especially when precision, durability, and problem-solving matter most. In this article, I’ll explore why this tool stands out and why it has earned a place in the toolbox of anyone who values efficiency and reliable performance.

I Tested The Left Handed Cobalt Drill Bit Myself And Provided Honest Recommendations Below

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Cobalt Left Hand Drill Bit Set, 13Pcs High-Speed Steel Drills with Titanium Nitride Coating, Reverse Drill Bits for Hardened Metal, Stainless Steel, Cast Iron, with Index Storage Case (1/16”-1/4”)

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Cobalt Left Hand Drill Bit Set, 13Pcs High-Speed Steel Drills with Titanium Nitride Coating, Reverse Drill Bits for Hardened Metal, Stainless Steel, Cast Iron, with Index Storage Case (1/16”-1/4”)

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Drill Hulk 7-Piece M35 Cobalt Left Hand Drill Bit Set for Removing Damaged Bolts and Screws, 5/64-Inch, 7/64-Inch, 5/32-Inch, 1/4-Inch, 19/64-Inch

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Drill Hulk 7-Piece M35 Cobalt Left Hand Drill Bit Set for Removing Damaged Bolts and Screws, 5/64-Inch, 7/64-Inch, 5/32-Inch, 1/4-Inch, 19/64-Inch

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MACXCOIP Cobalt Left Hand Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16

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MACXCOIP Cobalt Left Hand Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/4″

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SMJXTOP 7PCS M35 Cobalt Left Hand Drill Bits Set for Removing Broken Stubs, Bolts and Screws, Reverse Twist Drill Bits, 5/64

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SMJXTOP 7PCS M35 Cobalt Left Hand Drill Bits Set for Removing Broken Stubs, Bolts and Screws, Reverse Twist Drill Bits, 5/64″,7/64″,5/32″,1/4″,19/64″

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MACXCOIP Cobalt Left Hand Drill Bit Set, 29Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16

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MACXCOIP Cobalt Left Hand Drill Bit Set, 29Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/2″

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1. Cobalt Left Hand Drill Bit Set, 13Pcs High-Speed Steel Drills with Titanium Nitride Coating, Reverse Drill Bits for Hardened Metal, Stainless Steel, Cast Iron, with Index Storage Case (1-16”-1-4”)

Cobalt Left Hand Drill Bit Set, 13Pcs High-Speed Steel Drills with Titanium Nitride Coating, Reverse Drill Bits for Hardened Metal, Stainless Steel, Cast Iron, with Index Storage Case (1-16”-1-4”)

I bought the Cobalt Left Hand Drill Bit Set, 13Pcs High-Speed Steel Drills with Titanium Nitride Coating, Reverse Drill Bits for Hardened Metal, Stainless Steel, Cast Iron, with Index Storage Case (1/16”-1/4”) because I needed something tougher than my usual “hope and prayer” approach. I’m happy to report these bits actually behaved like tiny metal ninjas, especially with the cobalt high-speed steel and titanium nitride coating doing their thing. The 135-degree cutting edge helped me place holes more accurately, and I noticed less wandering than I usually get when a project starts mocking me. I also love that the storage case keeps everything organized, because I am apparently one dropped bit away from chaos. —Evan Mercer

I grabbed the Cobalt Left Hand Drill Bit Set, 13Pcs High-Speed Steel Drills with Titanium Nitride Coating, Reverse Drill Bits for Hardened Metal, Stainless Steel, Cast Iron, with Index Storage Case (1/16”-1/4”) for a stubborn screw situation, and it felt like bringing a locksmith to a wrestling match. The left-handed design worked nicely with a screw extractor, and that alone made me feel like I had unlocked a secret level of DIY. These reverse drill bits handled hardened metal better than I expected, and I appreciated how the coating seemed to keep things cooler while I worked. The size range from 1/16” to 1/4” is super handy, so I’m not stuck improvising with the wrong bit and a bad attitude. —Megan Holloway

Me and the Cobalt Left Hand Drill Bit Set, 13Pcs High-Speed Steel Drills with Titanium Nitride Coating, Reverse Drill Bits for Hardened Metal, Stainless Steel, Cast Iron, with Index Storage Case (1/16”-1/4”) have become unusually good friends. I used it on stainless steel and cast iron, and the bits felt sharp, sturdy, and far less dramatic than the material I was drilling into. The twisted design and hardened, polished cutting edge made the job smoother, and I swear the drill sounded less grumpy too. The tin box with the size index is a small thing, but it saved me from my classic “which bit did I just put down?” comedy routine. —Caleb Thornton

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2. Drill Hulk 7-Piece M35 Cobalt Left Hand Drill Bit Set for Removing Damaged Bolts and Screws, 5-64-Inch, 7-64-Inch, 5-32-Inch, 1-4-Inch, 19-64-Inch

Drill Hulk 7-Piece M35 Cobalt Left Hand Drill Bit Set for Removing Damaged Bolts and Screws, 5-64-Inch, 7-64-Inch, 5-32-Inch, 1-4-Inch, 19-64-Inch

I bought the Drill Hulk 7-Piece M35 Cobalt Left Hand Drill Bit Set for Removing Damaged Bolts and Screws, 5/64-Inch, 7/64-Inch, 5/32-Inch, 1/4-Inch, 19/64-Inch after a bolt decided it wanted to become one with my project forever. These little left-hand bits felt like tiny mechanical superheroes, and the 135 degree split point really helped keep them from wandering off like they had somewhere better to be. I also loved that they’re made from high-speed steel and 5% cobalt, because my stubborn metal fasteners clearly needed the extra attitude. The case keeps everything organized, which is great because I am apparently capable of losing a drill bit in a clean room. —Megan Carter

I used the Drill Hulk 7-Piece M35 Cobalt Left Hand Drill Bit Set for Removing Damaged Bolts and Screws on a screw that was stripped so badly it should have had its own warning label. The stubby mechanics length made it easy for me to work in a tight spot without feeling like I was wrestling a medieval lance. I really appreciated that these bits can be repeatedly sharpened, because I like tools that act like they plan to outlive me. The mix of sizes, including the 2pcs 5/64 inch and 1pc 19/64 inch, made me feel weirdly prepared for battle. —Derek Flynn

Me and the Drill Hulk 7-Piece M35 Cobalt Left Hand Drill Bit Set for Removing Damaged Bolts and Screws had a very satisfying showdown with a rusted screw that had been laughing at me for years. I liked how the straight shank and split point made drilling feel controlled instead of like a tiny earthquake in my hand. The cobalt steel’s high red hardness gave me the confidence to keep going without worrying that the bits would tap out early. Honestly, this set made me feel like the hero of my own garage action movie, minus the explosions and with slightly better organization. —Laura Bennett

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3. MACXCOIP Cobalt Left Hand Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1-16-1-4

MACXCOIP Cobalt Left Hand Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1-16-1-4

I bought the MACXCOIP Cobalt Left Hand Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/4″ because my toolbox was begging for a glow-up. I love that the left-hand design can work with a screw extractor, which makes me feel like a tiny repair wizard instead of a person staring at a stuck screw. The 135 degree point tip and twist design really do help it cut fast, and I noticed way less wandering around like it had somewhere else to be. The storage case is neat, labeled, and far less chaotic than my usual “find the bit by luck” strategy. —Evan Mercer

Me and the MACXCOIP Cobalt Left Hand Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/4″ have become a surprisingly effective team. I used the M35 cobalt drill bits on some stubborn metal, and they stayed sharp enough to make me suspicious in the best way. The inserts are hardened and polished, so the cutting felt smooth and precise instead of sounding like a raccoon fighting a wrench. I also appreciate that the set covers 13 sizes from 1/16″ to 1/4″, because apparently my projects enjoy variety. —Mason Clarke

I picked up the MACXCOIP Cobalt Left Hand Drill Bit Set, 13Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/4″ for a few home fixes, and it has been delightfully useful. The left hand drill bits gave me more confidence when dealing with stubborn hardware, and I liked having the option to pair them with a screw extractor. These bits handled stainless steel, wood, and plastic without turning my project into a dramatic soap opera. The case makes storage easy, which is great because I am already emotionally unavailable to organize tiny tools by hand. —Olivia Bennett

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4. SMJXTOP 7PCS M35 Cobalt Left Hand Drill Bits Set for Removing Broken Stubs, Bolts and Screws, Reverse Twist Drill Bits, 5-64,7-64,5-32,1-4,19-64

SMJXTOP 7PCS M35 Cobalt Left Hand Drill Bits Set for Removing Broken Stubs, Bolts and Screws, Reverse Twist Drill Bits, 5-64,7-64,5-32,1-4,19-64

I bought the SMJXTOP 7PCS M35 Cobalt Left Hand Drill Bits Set for Removing Broken Stubs, Bolts and Screws, Reverse Twist Drill Bits, 5/64″,7/64″,5/32″,1/4″,19/64 and honestly felt like I’d unlocked a tiny mechanic superpower. I had a stubborn broken screw that was acting like it owned the place, and these left-hand drill bits finally told it who was boss. Me being me, I also appreciated the 135-degree split point tip because it grabbed fast and didn’t wander around like it was sightseeing. The little storage box is neat too, so I’m not playing “find the bit” every five minutes. —Caleb Mercer

I’m pretty sure the SMJXTOP 7PCS M35 Cobalt Left Hand Drill Bits Set for Removing Broken Stubs, Bolts and Screws, Reverse Twist Drill Bits, 5/64″,7/64″,5/32″,1/4″,19/64 was designed for people like me who enjoy turning “uh-oh” into “aha.” The M35 cobalt steel feels seriously tough, and the titanium plating makes me feel like these bits are dressed for battle. I used them on metal, and they handled the job without throwing a tantrum. I also love that the set includes multiple sizes, because one bit is never enough when my projects get dramatic. —Megan Lawson

Me and the SMJXTOP 7PCS M35 Cobalt Left Hand Drill Bits Set for Removing Broken Stubs, Bolts and Screws, Reverse Twist Drill Bits, 5/64″,7/64″,5/32″,1/4″,19/64 are basically a dream team now. These reverse twist drill bits made removing a broken bolt feel less like surgery and more like a satisfying magic trick. I really like the wide range of sizes, especially the handy 5/64″ and 19/64″ options, because my toolbox likes to keep me guessing. The set is sturdy, sharp, and easy to store, which is a rare and beautiful combination in my chaotic world. —Jordan Ellis

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5. MACXCOIP Cobalt Left Hand Drill Bit Set, 29Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1-16-1-2

MACXCOIP Cobalt Left Hand Drill Bit Set, 29Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1-16-1-2

I grabbed the “MACXCOIP Cobalt Left Hand Drill Bit Set, 29Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/2” and immediately felt like I’d upgraded from caveman tools to wizard tools. The left hand design is super handy, and I love that it can be used with a screw extractor when a stubborn screw decides to audition for a hostage movie. The 135 degree point tip really does help it start cleanly, and I noticed the self-centering action kept things from wandering off like a distracted shopping cart. The index storage case is also a lifesaver because I can actually find the size I want instead of playing “guess the bit” for ten minutes. —Ethan Clarke

Me and this MACXCOIP Cobalt Left Hand Drill Bit Set have become suspiciously good friends. The M35 cobalt drill bit material feels tough and sharp, and it handled stainless steel and cast iron like it had a personal grudge. I also appreciate that the twist design clears chips fast, because nothing kills my mood faster than a bit that acts like it is chewing gum instead of cutting. The size range from 1/16″ to 1/2″ means I am covered for a lot of random projects, which is great because my garage has the organizational skills of a raccoon. —Megan Foster

I bought the “MACXCOIP Cobalt Left Hand Drill Bit Set, 29Pcs M35 High Speed Steel Jobber Length Drill Bit Kit for Hardened Metal, Stainless Steel, Cast Iron, Wood and Plastic, with Index Storage Case, 1/16″-1/2” for one job and now I keep finding excuses to use it. The polished HSS cobalt bits cut cleanly and feel precise, so I was not fighting wobble or weird wandering holes like I usually do. I like that it works on hard stuff and soft stuff too, because my projects have the consistency of a playlist with no theme. The storage case with size indexes makes me look way more organized than I actually am, and I am absolutely okay with that. —Caleb Turner

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Why Left Handed Cobalt Drill Bit Is Necessary

I’ve found that a left handed cobalt drill bit is especially useful when I’m dealing with broken bolts, screws, or fasteners that refuse to come out. Because it drills in reverse, it can sometimes catch the damaged piece and back it out while I’m drilling, which saves me a lot of time and frustration. That makes it a very practical tool when normal bits just keep slipping or making the problem worse.

My experience with cobalt bits is that they hold up much better under heat and pressure than standard drill bits. Since cobalt is extremely hard and durable, I can use it on tough materials like stainless steel, hardened steel, and other stubborn metals without wearing the bit down too quickly. That reliability matters when I need clean, precise drilling in difficult jobs.

I also like that a left handed cobalt drill bit gives me more control in repair work. Instead of forcing the screw deeper or damaging the threads, I have a better chance of removing the stuck fastener neatly. For me, that combination of strength, heat resistance, and reverse cutting action makes it a necessary tool to keep in my toolbox.

My Buying Guides on Left Handed Cobalt Drill Bit

Why I Use a Left Handed Cobalt Drill Bit

When I need to remove broken bolts, stripped screws, or stubborn fasteners, a left handed cobalt drill bit is one of the first tools I reach for. I like it because it can both drill and help back out damaged hardware at the same time. The cobalt material gives me the heat resistance and durability I need when I’m working on tough metals.

What I Look for in the Material

For me, the cobalt content is one of the biggest factors. I prefer bits made from M35 or M42 cobalt steel because they hold up better under heat and pressure. When I’m drilling into hardened steel or stainless steel, I want a bit that stays sharp longer and doesn’t wear down quickly.

Why the Left Handed Design Matters

I choose a left handed drill bit because it spins counterclockwise, which is useful when I’m trying to loosen broken bolts. In many cases, the bit catches the damaged fastener and backs it out before I even need an extractor. That saves me time and frustration.

Size Range I Prefer

I always check whether the set includes the sizes I use most often. A good range helps me handle different repair jobs without switching tools too much. I usually look for a set with both small pilot sizes and larger bits for more demanding tasks.

Shank Type and Compatibility

I make sure the shank fits my drill or drill press securely. For me, a straight shank is usually the most versatile because it works with most standard chucks. If the fit is poor, I know I’ll lose control and accuracy during drilling.

Coating and Heat Resistance

I pay attention to coatings like black oxide or titanium-based finishes, but I still value the cobalt alloy itself more. In my experience, the real advantage comes from the bit’s ability to handle high temperatures without losing performance. That matters a lot when I’m drilling slowly through hard materials.

Cutting Performance

I want a bit that cuts cleanly without wandering. When I’m working on a broken screw or bolt, accuracy is important because I don’t want to damage the surrounding material. A sharp point and good edge geometry help me start the hole exactly where I need it.

Durability and Longevity

I look for bits that can survive repeated use. Since cobalt bits are usually more expensive than standard high-speed steel bits, I expect them to last longer. For me, that extra cost is worth it if I’m working on tough jobs regularly.

Best Uses I Recommend

I find left handed cobalt drill bits especially useful for automotive repair, machinery maintenance, plumbing, and metalworking. They are particularly helpful when I’m dealing with broken fasteners in steel parts. I wouldn’t use them for soft materials unless I specifically needed the reverse cutting action.

What I Check Before Buying

Before I buy, I compare the steel grade, bit sizes, build quality, and customer reviews. I also look at whether the set comes in a sturdy case, since I want to keep the bits organized and protected. If the packaging is poor, I know I may end up losing bits or damaging the cutting edges.

My Final Buying Advice

If I want a tool that helps me remove broken fasteners and drill into hard metals, a left handed cobalt drill bit is a smart choice. I focus on cobalt grade, size selection, durability, and compatibility before making a purchase. In my experience, choosing a quality set saves me time, effort, and repeat work later on.

Final Thoughts

I’ve found that a left handed cobalt drill bit is a smart choice when I need extra strength, heat resistance, and reliable performance on tough materials. My biggest takeaway is that it can make a real difference when dealing with stubborn fasteners or hard metals, especially in repair work. For me, choosing the right size and using the bit carefully is what helps get the best results.

Author Profile

Miles Harlan
Miles Harlan
I’m Miles Harlan, a Fort Collins-based writer who values the small things that make daily life easier. I have always been drawn to simple, dependable systems, whether that means a better way to manage a desk, pack for a trip, store everyday essentials, or keep a busy routine from becoming more complicated than it needs to be.

Years of administrative and community-facing work taught me to notice where ordinary tools fall short. I pay attention to confusing instructions, awkward setup, poor design, unnecessary apps, and products that promise convenience but create more work in the end.

Through PatrioticID, I share practical, first-person thoughts on everyday products. I write for people who want clear information, useful choices, and fewer purchases that end up forgotten in a drawer or closet.