I bought these in 2012 when I wrote my review it was 2017. I originally bought this for small projects where plastic and tin were drilled. It worked fine for my needs. Most of what I had to go through was cutting and sanding 2 1cm diameter holes and altoid sheet metal. It did the job well. However, I think tin is the best it will go through. I later used one of the many parts that come with the kit to remove rust from my bike. That's when I encountered a problem. In the middle of that session, he accidentally switched off. I was 16 at the time and had no idea what the problem was. I thought the adapter burned out or something. I didn't throw it away, but left it in the closet until 2017. I had to use it again to remove the color and was confident I could get it working again. The adapter wasn't the problem, I opened it up and saw that the cable going to the switch had somehow come loose. I soldered it and voila it worked. I have removed the paint and will soon collect the rust from the bike. 1 star deducted for inconvenience.