We recently built a railing that required punching 5/8″ hole in 3/4″ round bar. We used our new fly press to slot punch the holes.
Once the holes were punched through, we used tapered pins called drifts to open up the holes to round and size them to 5/8″.
Once the holes were sized, they received a bronze rivet that was hammered over on both sides. Here is a picture of us installing the finished railing. We will get some nice full shots of this once the house is in a more finished state.