CO14B 14-Piece Cobalt Drill Bit Set with Case | Metal drilling, drill bits set to drill holes in metal, M42, three-flat shank, drill bits for stainless steel

This BOSCH Cobalt M42 3/8" drill bit performs extremely well, especially on hard metals. It made drilling feel almost effortless. Fit: Fits securely in standard drill chucks thanks to the three-flat shank design, with no slipping during use. Size: The 3/8" size is accurate and consistent, making clean and precise holes in various materials. Ease of Use: Very easy to use. It stays stable while drilling and doesn’t require excessive force to cut through tough metal. Compatibility: Works well across a range of materials including stainless steel, cast iron, and aluminum without issue. Case: Packaging is simple and protective enough to keep the bit safe during storage and transport. Appearance: Clean, professional look with a solid cobalt finish that reflects its heavy-duty design. Overall, this drill bit performs like a high-quality tool should. It cut through hard metal almost like melted butter, making it a reliable choice for demanding drilling tasks.

I bought the 14-piece cobalt set (upgrade over the Bosch titanium sets) almost two years ago (Jan 2024). I have been impressed enough with their performance to feel compelled to come back and review them, as well as buy a larger set (21-piece cobalt, which has a few sizes and duplicates that the 14-piece set doesn't include). In addition to occasional use of various sizes over the last two years on wood, PVC pipe, and aluminum, I used two of the bits in a single project to drill over a hundred holes in mild steel angle iron and rectangular tubing. I used a drill press, set up at a slower speed, along with plenty of cutting oil (sometimes reapplying midway through drilling a hole). In line with other bits I've used in the past, I expected the two bits I was repeatedly using to dull to the point of uselessness part-way through the project. Much to my surprise, both bits survived and still cut practically like they are new. Bottom line, if you are using these bits to drill into mild steel with a drill press set at a slower speed and generous application of cutting oil, these bits are a fantastic choice. I have also used these bits to drill into aluminum, PVC pipe, and woods of various hardnesses with absolutely no issues. Highly recommend any of the Bosch M42 cobalt bits.

Anything bosch makes is good, but i feel like they have it down pat when it comes to stuff like twist drills and bits. The M42 cobalt keeps the drill from getting too hot and also acts as a "lubricant", both contributing to keeping a sharp cutting edge, giving it quality and ease of use. These factors reduce the need for either resharpening, or worst, replacing the drill. The cost of cobalt bits are what scares people away, but if you're gonna be using it more than 2 or 3 times, its worth the upgrade from black oxide or a coated bit, thus giving it great value for money. The "M42" is a reference for the amount of cobalt used in the "material makeup" of the bit, with 8% cobalt being used in M42, and 5% cobalt in M35. Both are great options, but i recommend getting an M42 version when possible. The use of cobalt doesnt change the size or shape of the drill, although some will have different flute counts and designs, some tips have a "no pilot hole" start and some will have different degrees of an angle at the head to help with different types of material. Overall, storage capacity will not change unless you opt for different lengths, such as mechanics and aviation length. To sum this up, this is a great drill that should last a long time if used correctly. Bosch is very prevalent in my drill cabinet, so dont be afraid to spend a little extra and get the good one!

It started with my wife saying in an unusually calm voice, “Can you come here (kitchen), please. I need help.” This was not something that was about to fall or burn. There was plenty of time. She was calm but there was something else in her tone of voice that I’m unaccustomed to hearing, which put a smile on my face even before the reveal. I didn’t see anything wrong. She moved the pan off the stove and showed me the lid was stuck and would not budge. “I was cooking and placed the lid from one of the soup pots kind of sideways over the pan. As it warmed up, the lid slid down and I can’t remove it. It’s stuck.” I tried. It was ‘sucked’ into the pan – a vacuum seal. Of course this was a new, high-end pan. My instructions were that it was OK to destroy the lid but don’t scratch the pan! I tried using kitchen wooden spoons for leverage and could have broken all of them. I wanted to boil the lid off but my bride of 25 years didn’t want the explosive approach leaving detritus around the kitchen. Although I sorely wanted to hear that "Pop!", I couldn’t argue that point. So off I went to the garage, laughing, holding a hot pan with a spot-welded lid on, or rather, in it. I used a hammer and a punch to make a vacuum breaking hole in the stainless lid. It was rounded and punched back. I tried to drill the hole with old carbide tipped bits. It was highly polished stainless and the bit slid around within the punch zones like it was playing hop-scotch. After polishing several old carbide bits to baby’s bottom smoothness, I punted for the evening, leaving the, to me, mystery meal, in a covered pan in the garage, a frustrated shady tree mechanic first. The next day I took out the big gun. A reciprocating hammer drill I acquired from a pawn shop before I learned how pawn shops acquired such inventory. And I had ordered new Bosch Cobalt drill bits from our friends at Amazon and they arrived immediately. I was taking no prisoners. That was a vacuum seal and all I had to do was put the smallest hole in the lid without de-flowering the pan. The new bits and the Terminator hammer-drill did the trick. But the hole made no difference. The lid winked at me and remained locked on. It was here to teach me something. This had become personal. When the audience knows you spent $30+ on drill bits and you don’t complete the job, ‘You have some ‘splaining to do!”. And you lose rank. Neither appealed to me on this rainy Sunday. It was time to get creative and invoke my inner brute. First, I had a lifetime supply (a toothpaste-sized tube) of food grade grease for drinking water o-ring seals. I decided to apply that over-priced vasoline around the lid in case it started to move. Next, I heated it with a heat gun, which I’m sure only warmed me up and didn’t affect the outcome. Then I decided I needed a rig that would suspend the pan by the pot handle on the lid so that in my brute-inspired rage, I could literally hammer the pan away from the lid using a nylon mallet. After some tinker-toy-like playing around, 2 two by fours, one on each side of the pan were to become the test bed for this gravity experiment. Across the 2 2x4s and through the handle I placed a perfectly shaped crow-bar-ish tool. It was wide and extremely hardened steel. The pan’s handle went under foot ,suspending my target impact-zone- the edge of the pan opposite the handle, at a perfect height and distance for the seated me to wale upon it in well-deserved vengeance for the two hours of spousal humiliation this contraption had foisted upon me. Now was my time for targeted violence, and by Amazon same-day service, I was going to have it! When you set up one of these not exactly industrially hardened rigs, and contemplate sudden impact at close proximity to the target, the unforeseen consequences always feel invited to attend the goings on. Having welcomed my fair share of such irritating and, if you chose to look at it this way, educational fiends, I was in no mood for them this time. The pan must be unscratched. Corrugated cardboard went underneath the entire rig, knowing it would blunt the force of my politely sized mallet. I knew the Workshop G_ds wanted the contents to launch heaven-ward and distribute themselves evenly around the garage, including the car, my bikes, and tools. The rig was ½” off the ground and I felt contents vomit potential was mitigated. The pan handle was ensconced in an old but, as yet, unused in the garage, t-shirt of mine and was under the sole of my padded shoe. Nothing was left to chance. I took a warm-up tap to see what might be waiting to bite me in the …. Nothing. The crow-bar-ish tool moved. I repositioned it with one end biting into the 2x4. Another firmer tap. Nothing moved or slid. This could work and without drama. I knew that was the voice of an optimist inviting wicked consequences. I took the mallet up high and smote that deviant pot (credits to the funniest song that I and my father ever heard by long gone folk-singer, Gamble Rogers, “Door to Door Bible Salesman”) at the far rim. And it just worked. The lid hung in the air, suspended 1/2" over. the pan which sat, contededly, on the corrugated cardboard of the garage floor. Those drill bits worked ;)

Very good quality. Definitely a good value compared to other brands.

These bits drill through steel easily.Well worth the price.

Work great and a steal for the money. Bosch hit this out of the park!

Greta drill bits stay sharp and don't go dull aslong as you take care of them and use a bit of oil. Have multiple sets would buy again.

El funcionamiento de esta broca es muy bueno, se pueden hacer fácilmente perforaciones al metal

Great drill bits.

Quality material.

Buen producto especial para taladrar acero inoxidable

I’m a hobbyist using these drill bits for steel, copper, and general household fixes and I’ve found them to be extremely durable and reliable. I’ve had no issues so far. The edges have held up well and consistently produce clean, precise holes. They’re well worth the investment in my opinion. The seller also provided excellent customer service. They stayed on top of the delivery and even sent a replacement when the package didn’t arrive by the designated time, without me having to reach out at all. Overall, a great product from Bosch and an excellent seller! Definitely would buy more if needed in the future