🔩 Cobalt Drill Bit by Bosch: CO2151 Review

I had a broken stainless steel bolt on my car's exhaust system that needed to be removed. I've tried all my drill bits but none drilled through stainless steel. I bought a set of cobalt drill bits from Bosch, successfully drilled out the screw and completed the exhaust system repair. I found I needed a bit of lubrication to allow the bit to cut into the stainless steel stud. These are excellent quality drill bits.

Simply poked through this strong aluminum with no tension, however the metal stuck to the bit until the coating wore off, after which it continued to work smoothly. I don't think the coating helped, but the bit is still as sharp as a blade after 20 1.5" dives without cutting lube. Normally I would lube, but aluminum conducts heat so well it's not really necessary. Definitely Bosch quality.

I used this bit to make an extra hole on my tall Simpson Strong-Tie L-Brackets that I was going to use to attach the deck posts . concrete foundations. It is important to have two wells to prevent rotation in the event of a major seismic event and this drill drilled 40 wells in about an hour with no problems. I used a drill press and carefully turned it off when the drill bit caught too much metal and got stuck.