I ended up having to replace the last set I had which was made by another manufacturer. The small parts either broke from too much pressure on them or broke off the base. I've only drilled wood with these bits so far and they've done a great job for that. I used to come across this when I needed to drill through metal. The base on which the drill is attached makes a very solid and non-slip impression. So at least for now they are really good and I have no complaints. I hope they last longer than the last set I bought on Amazon from another brand. But I love these drill bits more than regular drill bits because they are so easy to get in and out of my cordless drill.