BOSCH CO21B 21-Piece Assorted Set with Included Case Cobalt M42 Metal Drill Bit with Three-Flat Shank for Drilling Applications in Stainless Steel, Cast Iron, Titanium, Light-Gauge Metal, Aluminum

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 ;)

I bought this because I already have a set of cobalt bits however my set didn't include a ½inch bit just ⅜. This is a nice sharp bit that cuts thru mild steel with ease. Remember to use a dedicated drilling/threading oil and it'll last you a long time. And I don't mean WD-40 when I say drilling oil!!

Bosch CO2151B - 1 piece 3/8 inch X 5 inch Cobalt M42 metal drill bit for $8 for use in stainless steel, Cast iron, Titanium, etc. Sharpness is very good, quality is good. The only thing that I miss is that Bosch used to be made in the US, now it’s made in China.

Cobalt bits are far superior to other drill bits; the added cobalt helps you cut far faster through hard metals. Once you've tried cobalt you won't go back to regular titanium coated bits. Just use lubricant and go slow and they will have a nice long life.These are a good value for name brand cobalt bits at ~$30 for the set of 14.

Drills holes nicely in the thick sheet metal that made my old black drills do a sort of red hot plasma-producing disintegration. But don't forget the cutting fluid!One a serious note, though, if one of the smaller drills slips out of their hole, they can fall out the openings on the backside of their plastic case. I lost two of them that way until I realized they were escape artists and sealed those holes up with hot glue.

I've had this set since May 2022, and while I don't do "a lot" of drilling, I do a fair share in metal. These are simply as good as it gets, they are simply amazing. Some of the infrequently used bits are still going like new. Some of the more frequently used ones are starting to wear a bit - but that's 3 years! I'm here because I'm getting a second set. These are the absolute BEST! Totally worth the extra $$.

These bits are amazing when you use them correctly and keep them cool. They saved me a lot of money. Drilled threw 10.9 control arm and ball joint bolts with ease. Very sharp. Male sure you use drilling oil to keep bit cool. Amazing product

Good price and durable! I used this to drill dimples on my barrel and so far it hasn't even started wearing down.