Guess what this is for, weird tool

Well... I guess we are back to center punches.
Yes and no.....they are actually "transfer punches". When you have a hole in a bracket or piece of metal (or wood) and you need to accurately locate the hole in the metal that the bracket will be installed onto you use these punches to transfer the hole from the bracket to the other piece of metal. So you hold the piece that has the hole against another piece of metal then you use the correct size transfer punch to punch a mark where you will drill the new hole. That's why they come in every size so that they fit snug in the hole and transfer the location accurately. These punches "transfer" the hole location to another piece of metal very accurately. If you've ever tried to hold a heavy piece of metal against another to locate the new hole you can see how they make the job a lot easier. I've used them transferring hole locations on body panels, custom brackets, installing custom heater brackets under the dash and for numerous other things that require a hole that has to be specifically placed with reference to another part. They used to be expensive but now you can get them cheap at HF!!