Thanks for your comments. I haven't really tried to push the potential of this tool. But, I have easily punched 3/16 and 1/4 inch holes through 1/8 mild steel. I've also sheared flat 1/8 and round 1/4. Most of this has been good enough for me so far. It was fun to bring this old tool back to life and best of all, it works!
I'm trying to do some research on its history and am hoping for additional feedback from other members. I don't believe it's a one-of-a-kind, but not sure how many survived over the years.