Forgot I had a two piece vise, coming in handy now. I made two end pieces for the frame rails to nest in. Clamp them together and holds everything vertical and in dimensional shape for welding.
The piece of alum in front is the first jig holder I made, it was too tight and needed a relief radius for the bend of ibeams. A little humor on that side project, first ones took me about 4 hours to figure out the cam for the cnc mill, the second set took about three min!!! One nice thing about fusion 360 is they give a brief description of what task at hand will do. Nice but if you don't know what any of it means then it's basically keep hitting buttons and operations until I find one that does what I want. That's why the 4 hours vs 4 min!!