Review on 🔋 POWERTEC QDB2013 16 Inch Cobalt 135° Superior Drill Bit by Doug Hinrichsen

Although I received my drill bits a day earlier than expected, I am disappointed with the bits. In theory, cobalt bits should cut through a grade 9 bolt like butter. These bits hardly leave any marks on the steel. A 9 amp drill is used for this. They work very well with regular steel. You pass the shadow of your average DeWalt or whatever you find in a big department store. I can see that for your daily work they will last a while as they work really well with medium grades of steel. Haven't tried them on cast iron yet but will get to that this week when I'm drilling out drain plugs on a Ford 302 block. They should be just the bits needed for tougher steel and cast iron, but no luck so far. PS I managed to break three 1/4" bits on a class 9 bolt.