I'd like to make a new pulley for the counter shaft of my lathe. The pulley is 9 inches in diameter and has two sheaves. My question is what to make it from. Searching online, it seems that the two most economical options are 6061T6 aluminum and grey cast iron. Either would cost around $60 for a 9 inch diameter 1.5 inch thick piece. Is there another option that I should consider? Of course, I would like something less expensive.