I’ve not had a great deal of luck when it comes to punches I refuse blind to pay hundreds for snap on ones to see if they are any good so I’m keen on trying out a few different things of making my own. My initial thoughts are around the idea of stainless steel. I know it’s not particularly hard in its normalised state but my thinking is and would be happy to be corrected here.... a good few whacks with a hammer and a few dress ups with a file will soon see the front and back ends work hardened to quite a hard state. I’ve frequently seen stainless get so hard hss won’t touch it so that’s ticked one box hopefully. The other thing is it should stay relatively ductile throughout its length and in the event of a miss hit it should bend rather than shatter My experience with punches are they are either too soft and mushroom up after a whack or two or too hard and they snap or chip. But you don’t see many made from stainless. Could this be a good material or should I look at others. Obviously I’m gonna have to try to confirm. Here is a 10mm parallel just dying for a clout. 4mm is probably the smallest I’ll make. Maybe 3.