I talked to my favorite sewing person and about bobbins for my 66. Yes, Nancy I am talking about you. Nancy told me to never use plastic bobbins in it. Singer gave me a phone number of a man who has parts. I called him for missing parts and to order bobbins. He told me to never use metal bobbins and to only use plastic because metal will ruin my machine. I am confused. Any imput from anyone? Kathie