I used to own a 31-15 that was motorized, so I know the capabilities. Hopefully this is a stupid question, but here goes. I purchased a machine someone had taken home from a factory that used treddle machines, who knows when. It had a 2 extra aftermarket cast bobbin carrier holders. It was missing a nut on the bottom, and everything that could be tightened, was loose. It had a home needle in it, and the drawer was full of vintage home needles. The bobbin hook was rounded and wouldn't catch the thread, so I ordered a new hook and carrier, and installed the correct needles. (Yes, I know which direction to put the needle in). The timing looks right with the exception of when I install the cast piece and the bobbin carrier group the machine seizes up. Loosen the retaining screws, and the machine functions fine, but the needle drags across the edge of the bobbin hook. Here's the question. Does anyone know the correct way to adjust the bar so it doesn't jam the bobbin hook into the iron carrier? I see a set screw where it can be rotated around, but I need it to be just a hair shorter, away from the bobbin carrier group.