I wouldn't give up my magnet system at gun point!
I found my steel plate at a manufacturer that produces metal stairs. He cut me a piece 30"x80" that is 3/16" thick. I have it on top of a solid core door that is dead flat and true. The guy I got it from cleaned it in some type of chemical bath that removed any corrosion and dirt. When I got it home, it got two good coats of light gray auto primer to protect it. I have made dozens of fixtures for clamping and holding components. It takes abit of time and a little investment to get it set up, but once you do, you will wonder how you got along without it.[sm=thumbup.gif]