Well I don't know if this is the right forum for this. If not, move it if so desired. I received my very first sewing machine. An old Singer Sonata 6610 10 stitch machine. I have no owners manual for it, and the one I downloaded from Singer doesn't list a bobbin size for it. I did what I thought was right, and bought just some random bobbin from walmart. It's a size 15. But I think it is the wrong size, as the machine jams up within the first 3 or 4 stitches. Can someone please tell me what size bobbin I need for my machine?