This may not be the final fix, but for now blowing out the stubs and securing the plates was the goal. This is not an unrailroady type fix. Other options include hot riveting (probably not in the plan), or use of Huck Bolts. A finished Huck Bolt repair is unsightly and requires a special tool to install. The problem with carriage bolts is the square shank under the head which would require broaching a square hole in the steel sheets. That to keep the head from turning and to allow the nut to be tightened. We can get high strength grade 5 or grade 8 machine bolts - not so much for carriage bolts. The bottom of any threaded fastener is visible from the bottom of the joint.