Review on 🔩 Precision Metal Jobber Twist Drill - 5.2mm Diameter for Professional Drilling by Paul Sanchez

These drill bits are crap for a keyless chuck. First, the thighs are smooth. There are no edges for a drill chuck except at them. So unless you have a drill press or an old chick with a wrench, they're going to slip. Second, they are not very sharp. They cut great for the first minute and once you surface and start a hole it slows down from there. I drilled 3/8 steel and it took 10-15 minutes to drill through. Don't waste money on them. They technically work, but not very well, so I cannot return them.