I'm building a one vessel electric system, and I need to drill several holes in my brand new stainless pot to hand the element and other fittings. I have read that a radio punch is the best tool for the job, but at over $100 for a single use tool, that somehow feels too expensive. The other tools that I've seen are the carbide tip hole saws, and step drill bits. What have you folks been using for drilling your kettles?