I bought a 13" sheldon yesterday. It wasn't under power when I checked it out and it looked to have been sitting for a long time. The price was right and it looked like a good project. I took the apron and saddle apart to inspect and clean things up before running it. It had the most worn out cross feed screw I have ever seen. I checked in my spare parts and found a screw that I acquired in some parts buy somewhere along the line. It was just about the perfect length and didn't appear to have any wear on it. The nut actually fit nice on it. I cut the the bad section off and pressed and pinned the good section from the donor screw on it. Here's some pics:
