That's actually a flaring tool, used to flare the ends of copper tubing to make a compression joint.
There is a tool that looks quite similar, it's called a swaging tool. West Marine carries a couple.
http://www.westmarine.com/webapp/wcs/stores/servlet/producte/10001/-1/10001/5657?&cid=chanintel&ci_src=14110944&ci_sku=5657
The difference between the flaring tool and the swaging tool is that the bolts are right next to the item being swaged rather than out at the ends. Much less bend in the steel pieces this way. Dave Cannell
