I am cleaning the old Singer 66 treadle I was given. At first, the handwheel was hard to turn, but brute force brought it around. Now it is totally stuck. The horizontal bar on the bottom front of the machine seems to be hitting on something. There is a thingy hanging down under the bobbin case (at least on that end) that has a semi-circular metal piece with a hole on each end. One end is attached to the hangy down piece, but the other end isn't attached to anything. I've tried to find diagrams of the bottom of a 66, without success. Does anybody have any ideas, or know what this is, or where I can find a diagram? Thanks, guys!