Hello, I inherited the Singer 306W from my mother. I have had it serviced and cleaned. I have one problem though. The repairman replaced the rubber wheel used to wind the bobbin with a piece that is too small and I cannot wind any of the bobbins. Where can I buy this rubber wheel? I really love this machine because it was Mama's and I want to be able to sew on her. Many thanks for any help you can give me.