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BOSCH cobalt drill bits are specially designed for drilling in hard steel. Thick web helix delivers fast material removal combined with increased durability for maximum efficiency and performance. Each bit is manufactured to exacting specifications and features a split point that starts on contact with no walking or skating, eliminating the need for a center punch.
From the Manufacturer
Bosch cobalt drill bits offer the best heat resistance and rigid thick web design for drilling in extremely hard and abrasive materials such as treated stainless steel (precipitation-hardened), cast iron and titanium.
Kanaka
September 4, 2025
Quality drill bit at a reasonable price. Great for drilling mild steel, stainless steel and aluminum. Works well in a hand drill as well as a drill press. Highly recommend these bits. Have used these Bosch cobalt bits a from 1/16â€-1/2†and all function well. Pull the trigger, these bits are worth it.
Customer
August 5, 2025
Very good quality and served my purpose perfectly.
Jason
July 24, 2025
After suffering with cheap Harbor Freight bits for years, I finally decided to get a good set. Found them on sale, so went for it. The first use was with a 7/64 bit to drill into a screw that had snapped off. Worked perfectly with a bit of oil. Very good bits. I might buy another set.
Mark M
May 29, 2025
Of course this size drill bit is very fragile so I have to buy them often. These are good quality and stay sharp for a good amount of time.
Randy G.
April 14, 2025
It does the job that it’s supposed to do
Goober9318
March 17, 2025
The bolt that secures the drive shaft to my Ironman elliptical broke in the flywheel mount. The bolt was threaded on the shaft and would not unthread. Can't find a replacement shaft so the only option was to drill out the center of the broken bolt and use an extractor to remove it. I set my drill press to the slowest speed and used cutting oil. I bought a set of cobalt Milwaukee bits (Home Depot) that barely scratched the surface. Discovered that they weren't even sharp out of the box! Used a bit sharpener and cutting oil to make very slow progress, one bit step up at a time. Several of the Milwaukee bits broke off and had to be re-shaped and sharpened. The extractors would NOT budge the broken bolt. I even bought a $40 Dewalt cobalt bit from Lowes and realized that I was going to have the same issue. I decided to take the risk with ordering these from Amazon. These Bosch bits tore straight through the broken bolt (without the need to sharpen!). Never could get the extractor to move the broken bolt, but after enough of the center of the bolt was cored out, the small layer of threads remaining were knocked out with a punch. Elliptical is back in service with new bolts and fasteners. I also bought a 1/2" bit that I never used, but I'm saving that for my next emergency. These are good sharp bits.
Psychofisherman
March 15, 2025
The perfect size for 1/4" bolts. This size will allow 1/4" bolts to go through whatever material your using. I used to "wobble" out the hole for proper fit, but after finding this perfect size up, perfect holes on the drill press, no reaming out at all.
Gabriel
March 10, 2025
First time drilling in aluminium and this bit did great. I finish installing the legs to our attic door. Highly recommended.
Vadim
February 19, 2025
great
TimofCanberra
January 30, 2025
these drills are very good and drill quickly through wood or metal. A size chart on the box would be helpful and while they are packaged well it can be hard on fingers getting them in or out of the box.
j cesar
January 27, 2025
buena calidad
Stephen
December 31, 2024
The brand speaks for itself! Very good and solid bits!
Jordan
December 15, 2024
BOSCH 21-Piece Cobalt Metal Drill Bit Set CO21 -I purchased these bits in December 2022, and they are still working fine.A few got broken over the years from misuse—apprentices not properly using them, cooling them, and keeping them square.I use them weekly in the trades. I drill into stainless steel panels with no problem.Solid drill bits, worth the value.
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