OK, I am having trouble w/my bobbin race area on my 15-91. I keep having trouble w/the thread messing up in the race, thought it was the bobbins so I ordered new ones. Then realized I had a problem w/the bobbin case...ordered a new one of those too. Now it seems it might be the hook race itself! When I put the bobbin case in, the hook race catches on the bobbin case. In other words the thing can't go all the way around because there is not enough clearance between the hook race and the bobbin case, where the screw is for the bobbin case tension adjustment does that make sense?) Have I got something put together wrong? Is it not supposed to go past that point? I hope my description made a little bit of sense and someone can help me. I am very much leaning towards the fact that I must have something put togther wrong. As of the writing of this I have not tried to check that myself because it is late and I should be sleeping, but I wanted to post here and see what expert advise I could get !