I made punches by buying brass tube in various sizes from model shops (in rapid decline, sadly) then Aralditing 2" lengths into hard balsa handles. The brass tube is pushed into the balsa until just the right amount of tube is showing. The balsa is shaped and varnished and the tube edge sharpened. A 30cm piece of tube is enough for 6 punches so I made spare sets that I sold off which covered the cost of the tube - ended up with free bread punches!
The old chromed-brass car radio aerials give tube in the finer diameters, as do old brass rod ferrules, and brass gun cartridges. My first bread punches were made from .22 cartridges.