This was my solution. First pic is an original and one of mine side by side, finished with a catalyst added to the enamel. Second pic is of the end of my first attempt. Next are the set of "dies" I welded up from a sturdy piece of T iron. One is the positive, the other the negative. Lay in a straight cut strip of sheet metal and bang away ! I used a socket set in a vise for the bottom of the recessed holes and a ball bearing welded on a bolt form the top. Drill the hole and bang away. The ends just take lots of "finessing". Lots of time involved, but the solution is acceptable.