I used the drill bits once to drill a hole in the 3/4 inch bottom of the jar. It only took about a minute after I started. I got a lot of stuff for the money. You worked on the first hole. I knew that before I bought them, but you have to know that they don't have a pilot crown. To overcome this I drilled a circular hole in the tree the size I wanted to drill and used it as a guide to drill a hole in the glass. Water must be used when drilling. It was a little tricky to start the hole but after that the drill did its job well, I will buy more if needed.