bkay

I had to laugh! I have to borrow a saying: "Re-doing old sewing machines ain't for sissies." I don't envy you on that one.

What I would do is put it on it's faceplate in a way that it doesn't rest on the tension or thread take up lever. I would try a paperback book (or 2), or a brick, or maybe a big roll of packing tape - anything that the faceplate can rest on that will keep the tension and thread take up lever not resting on anything. I just did a demo photo. It's not a 15-91, but it shows what I'm talking about. It has a knob on the faceplate and that was what was on my bench today. Just make sure that you don't bend anything on the face. Then drop your oil on that screw and blow it on high with a hairdryer the next day and see if it moves. (I've even heard of putting an oiled machine in your car in the sun.)

bk