The Armour Archive

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1874964599

has any one had any experiance with somthing like this?

I don't see how you could hold any sheet metal securely and pound it with a sledgehammer to cut out parts. This is probably for cutting out simple shapes off of a car body.

Reminds me of a big ole can opener.

You can get basically the same thing for a standard air chisel-they're mostly useless, unless you need to cut a hole in a 55 gal drum or something...