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

Great bit set!
This is a great drill bit set. The reason I purchased this set is because I needed to drill and tap a hole in the end of a lawnmower engine crankshaft. Rather than buying just that drill bit I decided to get a whole set, because I knew I would need drill bits again. I decided to go with this set over others because it is 8% cobalt whereas most others are only 5%, and this one includes a 1/2″ bit and most others don’t. These work amazing! Drilling the crankshaft was a breeze. I put some oil on it, and it practically screwed into the metal. I have since then drilled many holes through aluminum and wood, and they just go right through. These bits are plenty long for what I need. If I ever need to replace these bits, I will be getting more of the same. It was money well spent.

Drills the Undrillable
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 2×4. 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 😉

Drilling a bolt
The drill bit is excellent. Works grate and fast. Through metal steel and case iron..

Las mejores brocas, que puedes encontrar en el mercado para perforar, el hierro forjado y el acero inoxidable

Sehr Gute bohren

J’ai commandé ce coffret de forets à métaux au cobalt pour une utilisation en mécanique automobile. Je dois dire que je ne suis pas déçu. J’ai pu utiliser les forets sur différents métaux (tendre, normal, dur, et même compliqué comme l’inox) et les forets ont à chaque fois parfaitement fonctionné. J’ai utilisé les forets pour l’extraction d’un boulon antivol de roue à l’aide d’une visseuse lors d’un dépannage sur le bord de la route et ceci très rapidement.Le coffret n’est pas bon marché, mais il vaut bien son prix, car les forets sont très eff