The 3 forward fusalage ribs ar riveted to the firewall with AN470AD4-4 rivets. The holes are all match drilled, but still need to be dimpled. Access is difficult for a squeezer so I used my pop rivet tool and my dimple die set with a hole in the center for a nail. I place one die on the back of the firewall the the other die on the front and pass a nail through the center. I put the nail in my pop rivet tool and give it a squeeze. I repeated the process for all 15 holes.
