Gordon, are you referring to the nut plates that slide over the edge of the frame before you set the body down on it?. I had to make some of these a few years ago, and found it to be relatively easy. I took sheet metal, and a piece heavy angle iron, close to the thickness of the frame, chucked it in the vise, hammered the metal in half, drilled a pilot hole in each of them. Then took a UNIBIT bored a hole through both halves, 7/16th's, then came back, drilled half the piece larger, then welded the nuts in all the plates. It might sound like a lot of work, but I was able to do it in a few hours. I made 8 nut plates. Make sure you make them deep enough to slide over the frame and reach the hole. Don't forget about the frame lacing/insulator material.