When I was in 9th grade, learning industrial arts (about 45 years ago) we did metal turning. We used hard maple pieces to spin the metal (aluminum an copper) onto the form. I remember making sure the wood tip was soaked in a pot of liquid wax every so often. You first tuned he form,making sure that no closed radius existed, then lightly scribed with a pencil he center of the metal blank,positioned it on the form, drew up the tail stock with a matching size base as the bottom of he form, and slowly applied pressure with the wood stick against the post on the rest. Only when the edge needing turning away did we use a metal square edger tool,but back then it was carbon steel. You can always use steel rounded tools,but the wood worked without marking the metal. For aluminum bowls you would dip it into a pot of molten wax, carefully scrape out a design and dip the piece into acid etching the design leaving the rest of the wax to mask that portion. With copper you did the same and dipped it into ammonia fertilizer solution. Today, just use a paste made of miracle grow. he patina forms quickly.
