Can anyone help? I bought a White Rotary because it seemed to run smoothly and looked taken care of. But every time the man at the shop starts to sew, the thread loops around the bobbin case and tangles up and jams. He said he hasn't seen this exact type of bobbin case before and not sure what problem is, but will clean parts and see if that works.Could the problem be in the threading ? possibly the timing? Or maybe even the needle? I am worried I may have thrown away my money....It is a FR429021 I know it is a Franklin Rotary sold by Sears, would anyone know the year?