This project is useable for just about any shape you want to do, but in this case, I needed an oval recess for a Painless door contact, because there was not enough room for both contact halves between the jam and the door. The thickness of material will vary depending on how deep you need to go, but for this one, I needed 1/8". I used steel, but you could also use aluminum depending on how many parts you want to make. The first pic shows the contact. What you need is a male and female die. I made the bottom out of 1/4", and cut the opening with a hole saw and file. The top die I made from 1/8" again the depth I needed to go. I also used another piece of 1/8 ( should have been thicker) for the backing plate, which will be the piece you are going to push with as well as flatening the surrounding metal as it streches. The next pic shows that the hole is bigger than the die, which will give the metal a place to go. You need the opening to be at least twice the metal thickness. The more gap you give it, the rounder the outer edge will be. I start by laying the metal under the bottom die, and square up two edges for reference. I then mark the hole onto the metal. Then, I put the metal on top of the bottom die and square up the two edges again. (where my fingers are) This now places the scribed hole directly over the opening. Now you can lay the top die within the scribed hole, lay the backing plate on top of that and give it a push in the press. You can do this in a vice, but it takes a lot of squeeze. If all goes well, it should look something like this. After some carefull measuring, welding, grinding and painting, you should have a recess that looks like it belongs there.